5159 lines
153 KiB
C
5159 lines
153 KiB
C
/* Optimize jump instructions, for GNU compiler.
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Copyright (C) 1987, 88, 89, 91-98, 1999 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* This is the jump-optimization pass of the compiler.
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It is run two or three times: once before cse, sometimes once after cse,
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and once after reload (before final).
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jump_optimize deletes unreachable code and labels that are not used.
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It also deletes jumps that jump to the following insn,
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and simplifies jumps around unconditional jumps and jumps
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to unconditional jumps.
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Each CODE_LABEL has a count of the times it is used
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stored in the LABEL_NUSES internal field, and each JUMP_INSN
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has one label that it refers to stored in the
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JUMP_LABEL internal field. With this we can detect labels that
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become unused because of the deletion of all the jumps that
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formerly used them. The JUMP_LABEL info is sometimes looked
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at by later passes.
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Optionally, cross-jumping can be done. Currently it is done
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only the last time (when after reload and before final).
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In fact, the code for cross-jumping now assumes that register
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allocation has been done, since it uses `rtx_renumbered_equal_p'.
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Jump optimization is done after cse when cse's constant-propagation
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causes jumps to become unconditional or to be deleted.
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Unreachable loops are not detected here, because the labels
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have references and the insns appear reachable from the labels.
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find_basic_blocks in flow.c finds and deletes such loops.
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The subroutines delete_insn, redirect_jump, and invert_jump are used
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from other passes as well. */
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#include "config.h"
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#include "system.h"
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#include "rtl.h"
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#include "flags.h"
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#include "hard-reg-set.h"
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#include "regs.h"
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#include "insn-config.h"
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#include "insn-flags.h"
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#include "insn-attr.h"
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#include "recog.h"
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#include "expr.h"
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#include "real.h"
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#include "except.h"
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#include "toplev.h"
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/* ??? Eventually must record somehow the labels used by jumps
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from nested functions. */
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/* Pre-record the next or previous real insn for each label?
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No, this pass is very fast anyway. */
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/* Condense consecutive labels?
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This would make life analysis faster, maybe. */
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/* Optimize jump y; x: ... y: jumpif... x?
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Don't know if it is worth bothering with. */
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/* Optimize two cases of conditional jump to conditional jump?
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This can never delete any instruction or make anything dead,
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or even change what is live at any point.
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So perhaps let combiner do it. */
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/* Vector indexed by uid.
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For each CODE_LABEL, index by its uid to get first unconditional jump
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that jumps to the label.
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For each JUMP_INSN, index by its uid to get the next unconditional jump
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that jumps to the same label.
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Element 0 is the start of a chain of all return insns.
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(It is safe to use element 0 because insn uid 0 is not used. */
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static rtx *jump_chain;
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/* List of labels referred to from initializers.
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These can never be deleted. */
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rtx forced_labels;
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/* Maximum index in jump_chain. */
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static int max_jump_chain;
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/* Set nonzero by jump_optimize if control can fall through
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to the end of the function. */
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int can_reach_end;
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/* Indicates whether death notes are significant in cross jump analysis.
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Normally they are not significant, because of A and B jump to C,
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and R dies in A, it must die in B. But this might not be true after
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stack register conversion, and we must compare death notes in that
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case. */
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static int cross_jump_death_matters = 0;
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static int init_label_info PROTO((rtx));
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static void delete_barrier_successors PROTO((rtx));
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static void mark_all_labels PROTO((rtx, int));
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static rtx delete_unreferenced_labels PROTO((rtx));
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static void delete_noop_moves PROTO((rtx));
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static int calculate_can_reach_end PROTO((rtx, int, int));
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static int duplicate_loop_exit_test PROTO((rtx));
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static void find_cross_jump PROTO((rtx, rtx, int, rtx *, rtx *));
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static void do_cross_jump PROTO((rtx, rtx, rtx));
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static int jump_back_p PROTO((rtx, rtx));
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static int tension_vector_labels PROTO((rtx, int));
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static void mark_jump_label PROTO((rtx, rtx, int));
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static void delete_computation PROTO((rtx));
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static void delete_from_jump_chain PROTO((rtx));
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static int delete_labelref_insn PROTO((rtx, rtx, int));
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static void mark_modified_reg PROTO((rtx, rtx));
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static void redirect_tablejump PROTO((rtx, rtx));
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static void jump_optimize_1 PROTO ((rtx, int, int, int, int));
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#ifndef HAVE_cc0
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static rtx find_insert_position PROTO((rtx, rtx));
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#endif
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/* Main external entry point into the jump optimizer. See comments before
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jump_optimize_1 for descriptions of the arguments. */
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void
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jump_optimize (f, cross_jump, noop_moves, after_regscan)
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rtx f;
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int cross_jump;
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int noop_moves;
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int after_regscan;
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{
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jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, 0);
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}
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/* Alternate entry into the jump optimizer. This entry point only rebuilds
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the JUMP_LABEL field in jumping insns and REG_LABEL notes in non-jumping
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instructions. */
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void
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rebuild_jump_labels (f)
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rtx f;
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{
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jump_optimize_1 (f, 0, 0, 0, 1);
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}
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/* Delete no-op jumps and optimize jumps to jumps
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and jumps around jumps.
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Delete unused labels and unreachable code.
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If CROSS_JUMP is 1, detect matching code
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before a jump and its destination and unify them.
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If CROSS_JUMP is 2, do cross-jumping, but pay attention to death notes.
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If NOOP_MOVES is nonzero, delete no-op move insns.
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If AFTER_REGSCAN is nonzero, then this jump pass is being run immediately
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after regscan, and it is safe to use regno_first_uid and regno_last_uid.
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If MARK_LABELS_ONLY is nonzero, then we only rebuild the jump chain
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and JUMP_LABEL field for jumping insns.
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If `optimize' is zero, don't change any code,
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just determine whether control drops off the end of the function.
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This case occurs when we have -W and not -O.
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It works because `delete_insn' checks the value of `optimize'
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and refrains from actually deleting when that is 0. */
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static void
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jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, mark_labels_only)
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rtx f;
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int cross_jump;
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int noop_moves;
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int after_regscan;
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int mark_labels_only;
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{
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register rtx insn, next;
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int changed;
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int old_max_reg;
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int first = 1;
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int max_uid = 0;
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rtx last_insn;
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cross_jump_death_matters = (cross_jump == 2);
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max_uid = init_label_info (f) + 1;
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/* If we are performing cross jump optimizations, then initialize
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tables mapping UIDs to EH regions to avoid incorrect movement
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of insns from one EH region to another. */
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if (flag_exceptions && cross_jump)
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init_insn_eh_region (f, max_uid);
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delete_barrier_successors (f);
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/* Leave some extra room for labels and duplicate exit test insns
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we make. */
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max_jump_chain = max_uid * 14 / 10;
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jump_chain = (rtx *) alloca (max_jump_chain * sizeof (rtx));
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bzero ((char *) jump_chain, max_jump_chain * sizeof (rtx));
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mark_all_labels (f, cross_jump);
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/* Keep track of labels used from static data;
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they cannot ever be deleted. */
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for (insn = forced_labels; insn; insn = XEXP (insn, 1))
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LABEL_NUSES (XEXP (insn, 0))++;
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check_exception_handler_labels ();
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/* Keep track of labels used for marking handlers for exception
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regions; they cannot usually be deleted. */
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for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
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LABEL_NUSES (XEXP (insn, 0))++;
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/* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
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notes and recompute LABEL_NUSES. */
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if (mark_labels_only)
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return;
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exception_optimize ();
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last_insn = delete_unreferenced_labels (f);
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if (!optimize)
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{
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/* CAN_REACH_END is persistent for each function. Once set it should
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not be cleared. This is especially true for the case where we
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delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
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the front-end before compiling each function. */
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if (calculate_can_reach_end (last_insn, 1, 0))
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can_reach_end = 1;
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/* Zero the "deleted" flag of all the "deleted" insns. */
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for (insn = f; insn; insn = NEXT_INSN (insn))
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INSN_DELETED_P (insn) = 0;
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/* Show that the jump chain is not valid. */
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jump_chain = 0;
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return;
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}
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#ifdef HAVE_return
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if (HAVE_return)
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{
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/* If we fall through to the epilogue, see if we can insert a RETURN insn
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in front of it. If the machine allows it at this point (we might be
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after reload for a leaf routine), it will improve optimization for it
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to be there. */
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insn = get_last_insn ();
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while (insn && GET_CODE (insn) == NOTE)
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insn = PREV_INSN (insn);
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if (insn && GET_CODE (insn) != BARRIER)
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{
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emit_jump_insn (gen_return ());
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emit_barrier ();
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}
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}
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#endif
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if (noop_moves)
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delete_noop_moves (f);
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/* If we haven't yet gotten to reload and we have just run regscan,
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delete any insn that sets a register that isn't used elsewhere.
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This helps some of the optimizations below by having less insns
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being jumped around. */
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if (! reload_completed && after_regscan)
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for (insn = f; insn; insn = next)
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{
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rtx set = single_set (insn);
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next = NEXT_INSN (insn);
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if (set && GET_CODE (SET_DEST (set)) == REG
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&& REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
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&& REGNO_FIRST_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
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/* We use regno_last_note_uid so as not to delete the setting
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of a reg that's used in notes. A subsequent optimization
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might arrange to use that reg for real. */
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&& REGNO_LAST_NOTE_UID (REGNO (SET_DEST (set))) == INSN_UID (insn)
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&& ! side_effects_p (SET_SRC (set))
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&& ! find_reg_note (insn, REG_RETVAL, 0))
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delete_insn (insn);
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}
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/* Now iterate optimizing jumps until nothing changes over one pass. */
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changed = 1;
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old_max_reg = max_reg_num ();
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while (changed)
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{
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changed = 0;
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for (insn = f; insn; insn = next)
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{
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rtx reallabelprev;
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rtx temp, temp1, temp2, temp3, temp4, temp5, temp6;
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rtx nlabel;
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int this_is_simplejump, this_is_condjump, reversep = 0;
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int this_is_condjump_in_parallel;
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#if 0
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/* If NOT the first iteration, if this is the last jump pass
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(just before final), do the special peephole optimizations.
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Avoiding the first iteration gives ordinary jump opts
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a chance to work before peephole opts. */
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if (reload_completed && !first && !flag_no_peephole)
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if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN)
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peephole (insn);
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#endif
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/* That could have deleted some insns after INSN, so check now
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what the following insn is. */
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next = NEXT_INSN (insn);
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/* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional
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jump. Try to optimize by duplicating the loop exit test if so.
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This is only safe immediately after regscan, because it uses
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the values of regno_first_uid and regno_last_uid. */
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if (after_regscan && GET_CODE (insn) == NOTE
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&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
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&& (temp1 = next_nonnote_insn (insn)) != 0
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&& simplejump_p (temp1))
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{
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temp = PREV_INSN (insn);
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if (duplicate_loop_exit_test (insn))
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{
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changed = 1;
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next = NEXT_INSN (temp);
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continue;
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}
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}
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if (GET_CODE (insn) != JUMP_INSN)
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continue;
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this_is_simplejump = simplejump_p (insn);
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this_is_condjump = condjump_p (insn);
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this_is_condjump_in_parallel = condjump_in_parallel_p (insn);
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/* Tension the labels in dispatch tables. */
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if (GET_CODE (PATTERN (insn)) == ADDR_VEC)
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changed |= tension_vector_labels (PATTERN (insn), 0);
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if (GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
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changed |= tension_vector_labels (PATTERN (insn), 1);
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/* If a dispatch table always goes to the same place,
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get rid of it and replace the insn that uses it. */
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if (GET_CODE (PATTERN (insn)) == ADDR_VEC
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|| GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
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{
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int i;
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rtx pat = PATTERN (insn);
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int diff_vec_p = GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC;
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int len = XVECLEN (pat, diff_vec_p);
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rtx dispatch = prev_real_insn (insn);
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for (i = 0; i < len; i++)
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if (XEXP (XVECEXP (pat, diff_vec_p, i), 0)
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!= XEXP (XVECEXP (pat, diff_vec_p, 0), 0))
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break;
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if (i == len
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&& dispatch != 0
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&& GET_CODE (dispatch) == JUMP_INSN
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&& JUMP_LABEL (dispatch) != 0
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/* Don't mess with a casesi insn. */
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&& !(GET_CODE (PATTERN (dispatch)) == SET
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&& (GET_CODE (SET_SRC (PATTERN (dispatch)))
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== IF_THEN_ELSE))
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&& next_real_insn (JUMP_LABEL (dispatch)) == insn)
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{
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redirect_tablejump (dispatch,
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XEXP (XVECEXP (pat, diff_vec_p, 0), 0));
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changed = 1;
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||
}
|
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}
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||
|
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reallabelprev = prev_active_insn (JUMP_LABEL (insn));
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||
|
||
/* If a jump references the end of the function, try to turn
|
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it into a RETURN insn, possibly a conditional one. */
|
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if (JUMP_LABEL (insn)
|
||
&& (next_active_insn (JUMP_LABEL (insn)) == 0
|
||
|| GET_CODE (PATTERN (next_active_insn (JUMP_LABEL (insn))))
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== RETURN))
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||
changed |= redirect_jump (insn, NULL_RTX);
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/* Detect jump to following insn. */
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||
if (reallabelprev == insn && condjump_p (insn))
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{
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||
next = next_real_insn (JUMP_LABEL (insn));
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||
delete_jump (insn);
|
||
changed = 1;
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||
continue;
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||
}
|
||
|
||
/* If we have an unconditional jump preceded by a USE, try to put
|
||
the USE before the target and jump there. This simplifies many
|
||
of the optimizations below since we don't have to worry about
|
||
dealing with these USE insns. We only do this if the label
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||
being branch to already has the identical USE or if code
|
||
never falls through to that label. */
|
||
|
||
if (this_is_simplejump
|
||
&& (temp = prev_nonnote_insn (insn)) != 0
|
||
&& GET_CODE (temp) == INSN && GET_CODE (PATTERN (temp)) == USE
|
||
&& (temp1 = prev_nonnote_insn (JUMP_LABEL (insn))) != 0
|
||
&& (GET_CODE (temp1) == BARRIER
|
||
|| (GET_CODE (temp1) == INSN
|
||
&& rtx_equal_p (PATTERN (temp), PATTERN (temp1))))
|
||
/* Don't do this optimization if we have a loop containing only
|
||
the USE instruction, and the loop start label has a usage
|
||
count of 1. This is because we will redo this optimization
|
||
everytime through the outer loop, and jump opt will never
|
||
exit. */
|
||
&& ! ((temp2 = prev_nonnote_insn (temp)) != 0
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||
&& temp2 == JUMP_LABEL (insn)
|
||
&& LABEL_NUSES (temp2) == 1))
|
||
{
|
||
if (GET_CODE (temp1) == BARRIER)
|
||
{
|
||
emit_insn_after (PATTERN (temp), temp1);
|
||
temp1 = NEXT_INSN (temp1);
|
||
}
|
||
|
||
delete_insn (temp);
|
||
redirect_jump (insn, get_label_before (temp1));
|
||
reallabelprev = prev_real_insn (temp1);
|
||
changed = 1;
|
||
}
|
||
|
||
/* Simplify if (...) x = a; else x = b; by converting it
|
||
to x = b; if (...) x = a;
|
||
if B is sufficiently simple, the test doesn't involve X,
|
||
and nothing in the test modifies B or X.
|
||
|
||
If we have small register classes, we also can't do this if X
|
||
is a hard register.
|
||
|
||
If the "x = b;" insn has any REG_NOTES, we don't do this because
|
||
of the possibility that we are running after CSE and there is a
|
||
REG_EQUAL note that is only valid if the branch has already been
|
||
taken. If we move the insn with the REG_EQUAL note, we may
|
||
fold the comparison to always be false in a later CSE pass.
|
||
(We could also delete the REG_NOTES when moving the insn, but it
|
||
seems simpler to not move it.) An exception is that we can move
|
||
the insn if the only note is a REG_EQUAL or REG_EQUIV whose
|
||
value is the same as "b".
|
||
|
||
INSN is the branch over the `else' part.
|
||
|
||
We set:
|
||
|
||
TEMP to the jump insn preceding "x = a;"
|
||
TEMP1 to X
|
||
TEMP2 to the insn that sets "x = b;"
|
||
TEMP3 to the insn that sets "x = a;"
|
||
TEMP4 to the set of "x = b"; */
|
||
|
||
if (this_is_simplejump
|
||
&& (temp3 = prev_active_insn (insn)) != 0
|
||
&& GET_CODE (temp3) == INSN
|
||
&& (temp4 = single_set (temp3)) != 0
|
||
&& GET_CODE (temp1 = SET_DEST (temp4)) == REG
|
||
&& (! SMALL_REGISTER_CLASSES
|
||
|| REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
|
||
&& (temp2 = next_active_insn (insn)) != 0
|
||
&& GET_CODE (temp2) == INSN
|
||
&& (temp4 = single_set (temp2)) != 0
|
||
&& rtx_equal_p (SET_DEST (temp4), temp1)
|
||
&& ! side_effects_p (SET_SRC (temp4))
|
||
&& ! may_trap_p (SET_SRC (temp4))
|
||
&& (REG_NOTES (temp2) == 0
|
||
|| ((REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUAL
|
||
|| REG_NOTE_KIND (REG_NOTES (temp2)) == REG_EQUIV)
|
||
&& XEXP (REG_NOTES (temp2), 1) == 0
|
||
&& rtx_equal_p (XEXP (REG_NOTES (temp2), 0),
|
||
SET_SRC (temp4))))
|
||
&& (temp = prev_active_insn (temp3)) != 0
|
||
&& condjump_p (temp) && ! simplejump_p (temp)
|
||
/* TEMP must skip over the "x = a;" insn */
|
||
&& prev_real_insn (JUMP_LABEL (temp)) == insn
|
||
&& no_labels_between_p (insn, JUMP_LABEL (temp))
|
||
/* There must be no other entries to the "x = b;" insn. */
|
||
&& no_labels_between_p (JUMP_LABEL (temp), temp2)
|
||
/* INSN must either branch to the insn after TEMP2 or the insn
|
||
after TEMP2 must branch to the same place as INSN. */
|
||
&& (reallabelprev == temp2
|
||
|| ((temp5 = next_active_insn (temp2)) != 0
|
||
&& simplejump_p (temp5)
|
||
&& JUMP_LABEL (temp5) == JUMP_LABEL (insn))))
|
||
{
|
||
/* The test expression, X, may be a complicated test with
|
||
multiple branches. See if we can find all the uses of
|
||
the label that TEMP branches to without hitting a CALL_INSN
|
||
or a jump to somewhere else. */
|
||
rtx target = JUMP_LABEL (temp);
|
||
int nuses = LABEL_NUSES (target);
|
||
rtx p;
|
||
#ifdef HAVE_cc0
|
||
rtx q;
|
||
#endif
|
||
|
||
/* Set P to the first jump insn that goes around "x = a;". */
|
||
for (p = temp; nuses && p; p = prev_nonnote_insn (p))
|
||
{
|
||
if (GET_CODE (p) == JUMP_INSN)
|
||
{
|
||
if (condjump_p (p) && ! simplejump_p (p)
|
||
&& JUMP_LABEL (p) == target)
|
||
{
|
||
nuses--;
|
||
if (nuses == 0)
|
||
break;
|
||
}
|
||
else
|
||
break;
|
||
}
|
||
else if (GET_CODE (p) == CALL_INSN)
|
||
break;
|
||
}
|
||
|
||
#ifdef HAVE_cc0
|
||
/* We cannot insert anything between a set of cc and its use
|
||
so if P uses cc0, we must back up to the previous insn. */
|
||
q = prev_nonnote_insn (p);
|
||
if (q && GET_RTX_CLASS (GET_CODE (q)) == 'i'
|
||
&& sets_cc0_p (PATTERN (q)))
|
||
p = q;
|
||
#endif
|
||
|
||
if (p)
|
||
p = PREV_INSN (p);
|
||
|
||
/* If we found all the uses and there was no data conflict, we
|
||
can move the assignment unless we can branch into the middle
|
||
from somewhere. */
|
||
if (nuses == 0 && p
|
||
&& no_labels_between_p (p, insn)
|
||
&& ! reg_referenced_between_p (temp1, p, NEXT_INSN (temp3))
|
||
&& ! reg_set_between_p (temp1, p, temp3)
|
||
&& (GET_CODE (SET_SRC (temp4)) == CONST_INT
|
||
|| ! modified_between_p (SET_SRC (temp4), p, temp2))
|
||
/* Verify that registers used by the jump are not clobbered
|
||
by the instruction being moved. */
|
||
&& ! regs_set_between_p (PATTERN (temp),
|
||
PREV_INSN (temp2),
|
||
NEXT_INSN (temp2)))
|
||
{
|
||
emit_insn_after_with_line_notes (PATTERN (temp2), p, temp2);
|
||
delete_insn (temp2);
|
||
|
||
/* Set NEXT to an insn that we know won't go away. */
|
||
next = next_active_insn (insn);
|
||
|
||
/* Delete the jump around the set. Note that we must do
|
||
this before we redirect the test jumps so that it won't
|
||
delete the code immediately following the assignment
|
||
we moved (which might be a jump). */
|
||
|
||
delete_insn (insn);
|
||
|
||
/* We either have two consecutive labels or a jump to
|
||
a jump, so adjust all the JUMP_INSNs to branch to where
|
||
INSN branches to. */
|
||
for (p = NEXT_INSN (p); p != next; p = NEXT_INSN (p))
|
||
if (GET_CODE (p) == JUMP_INSN)
|
||
redirect_jump (p, target);
|
||
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
}
|
||
|
||
/* Simplify if (...) { x = a; goto l; } x = b; by converting it
|
||
to x = a; if (...) goto l; x = b;
|
||
if A is sufficiently simple, the test doesn't involve X,
|
||
and nothing in the test modifies A or X.
|
||
|
||
If we have small register classes, we also can't do this if X
|
||
is a hard register.
|
||
|
||
If the "x = a;" insn has any REG_NOTES, we don't do this because
|
||
of the possibility that we are running after CSE and there is a
|
||
REG_EQUAL note that is only valid if the branch has already been
|
||
taken. If we move the insn with the REG_EQUAL note, we may
|
||
fold the comparison to always be false in a later CSE pass.
|
||
(We could also delete the REG_NOTES when moving the insn, but it
|
||
seems simpler to not move it.) An exception is that we can move
|
||
the insn if the only note is a REG_EQUAL or REG_EQUIV whose
|
||
value is the same as "a".
|
||
|
||
INSN is the goto.
|
||
|
||
We set:
|
||
|
||
TEMP to the jump insn preceding "x = a;"
|
||
TEMP1 to X
|
||
TEMP2 to the insn that sets "x = b;"
|
||
TEMP3 to the insn that sets "x = a;"
|
||
TEMP4 to the set of "x = a"; */
|
||
|
||
if (this_is_simplejump
|
||
&& (temp2 = next_active_insn (insn)) != 0
|
||
&& GET_CODE (temp2) == INSN
|
||
&& (temp4 = single_set (temp2)) != 0
|
||
&& GET_CODE (temp1 = SET_DEST (temp4)) == REG
|
||
&& (! SMALL_REGISTER_CLASSES
|
||
|| REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
|
||
&& (temp3 = prev_active_insn (insn)) != 0
|
||
&& GET_CODE (temp3) == INSN
|
||
&& (temp4 = single_set (temp3)) != 0
|
||
&& rtx_equal_p (SET_DEST (temp4), temp1)
|
||
&& ! side_effects_p (SET_SRC (temp4))
|
||
&& ! may_trap_p (SET_SRC (temp4))
|
||
&& (REG_NOTES (temp3) == 0
|
||
|| ((REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUAL
|
||
|| REG_NOTE_KIND (REG_NOTES (temp3)) == REG_EQUIV)
|
||
&& XEXP (REG_NOTES (temp3), 1) == 0
|
||
&& rtx_equal_p (XEXP (REG_NOTES (temp3), 0),
|
||
SET_SRC (temp4))))
|
||
&& (temp = prev_active_insn (temp3)) != 0
|
||
&& condjump_p (temp) && ! simplejump_p (temp)
|
||
/* TEMP must skip over the "x = a;" insn */
|
||
&& prev_real_insn (JUMP_LABEL (temp)) == insn
|
||
&& no_labels_between_p (temp, insn))
|
||
{
|
||
rtx prev_label = JUMP_LABEL (temp);
|
||
rtx insert_after = prev_nonnote_insn (temp);
|
||
|
||
#ifdef HAVE_cc0
|
||
/* We cannot insert anything between a set of cc and its use. */
|
||
if (insert_after && GET_RTX_CLASS (GET_CODE (insert_after)) == 'i'
|
||
&& sets_cc0_p (PATTERN (insert_after)))
|
||
insert_after = prev_nonnote_insn (insert_after);
|
||
#endif
|
||
++LABEL_NUSES (prev_label);
|
||
|
||
if (insert_after
|
||
&& no_labels_between_p (insert_after, temp)
|
||
&& ! reg_referenced_between_p (temp1, insert_after, temp3)
|
||
&& ! reg_referenced_between_p (temp1, temp3,
|
||
NEXT_INSN (temp2))
|
||
&& ! reg_set_between_p (temp1, insert_after, temp)
|
||
&& ! modified_between_p (SET_SRC (temp4), insert_after, temp)
|
||
/* Verify that registers used by the jump are not clobbered
|
||
by the instruction being moved. */
|
||
&& ! regs_set_between_p (PATTERN (temp),
|
||
PREV_INSN (temp3),
|
||
NEXT_INSN (temp3))
|
||
&& invert_jump (temp, JUMP_LABEL (insn)))
|
||
{
|
||
emit_insn_after_with_line_notes (PATTERN (temp3),
|
||
insert_after, temp3);
|
||
delete_insn (temp3);
|
||
delete_insn (insn);
|
||
/* Set NEXT to an insn that we know won't go away. */
|
||
next = temp2;
|
||
changed = 1;
|
||
}
|
||
if (prev_label && --LABEL_NUSES (prev_label) == 0)
|
||
delete_insn (prev_label);
|
||
if (changed)
|
||
continue;
|
||
}
|
||
|
||
#ifndef HAVE_cc0
|
||
/* If we have if (...) x = exp; and branches are expensive,
|
||
EXP is a single insn, does not have any side effects, cannot
|
||
trap, and is not too costly, convert this to
|
||
t = exp; if (...) x = t;
|
||
|
||
Don't do this when we have CC0 because it is unlikely to help
|
||
and we'd need to worry about where to place the new insn and
|
||
the potential for conflicts. We also can't do this when we have
|
||
notes on the insn for the same reason as above.
|
||
|
||
We set:
|
||
|
||
TEMP to the "x = exp;" insn.
|
||
TEMP1 to the single set in the "x = exp;" insn.
|
||
TEMP2 to "x". */
|
||
|
||
if (! reload_completed
|
||
&& this_is_condjump && ! this_is_simplejump
|
||
&& BRANCH_COST >= 3
|
||
&& (temp = next_nonnote_insn (insn)) != 0
|
||
&& GET_CODE (temp) == INSN
|
||
&& REG_NOTES (temp) == 0
|
||
&& (reallabelprev == temp
|
||
|| ((temp2 = next_active_insn (temp)) != 0
|
||
&& simplejump_p (temp2)
|
||
&& JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
|
||
&& (temp1 = single_set (temp)) != 0
|
||
&& (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
|
||
&& (! SMALL_REGISTER_CLASSES
|
||
|| REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
|
||
&& GET_CODE (SET_SRC (temp1)) != REG
|
||
&& GET_CODE (SET_SRC (temp1)) != SUBREG
|
||
&& GET_CODE (SET_SRC (temp1)) != CONST_INT
|
||
&& ! side_effects_p (SET_SRC (temp1))
|
||
&& ! may_trap_p (SET_SRC (temp1))
|
||
&& rtx_cost (SET_SRC (temp1), SET) < 10)
|
||
{
|
||
rtx new = gen_reg_rtx (GET_MODE (temp2));
|
||
|
||
if ((temp3 = find_insert_position (insn, temp))
|
||
&& validate_change (temp, &SET_DEST (temp1), new, 0))
|
||
{
|
||
next = emit_insn_after (gen_move_insn (temp2, new), insn);
|
||
emit_insn_after_with_line_notes (PATTERN (temp),
|
||
PREV_INSN (temp3), temp);
|
||
delete_insn (temp);
|
||
reallabelprev = prev_active_insn (JUMP_LABEL (insn));
|
||
|
||
if (after_regscan)
|
||
{
|
||
reg_scan_update (temp3, NEXT_INSN (next), old_max_reg);
|
||
old_max_reg = max_reg_num ();
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Similarly, if it takes two insns to compute EXP but they
|
||
have the same destination. Here TEMP3 will be the second
|
||
insn and TEMP4 the SET from that insn. */
|
||
|
||
if (! reload_completed
|
||
&& this_is_condjump && ! this_is_simplejump
|
||
&& BRANCH_COST >= 4
|
||
&& (temp = next_nonnote_insn (insn)) != 0
|
||
&& GET_CODE (temp) == INSN
|
||
&& REG_NOTES (temp) == 0
|
||
&& (temp3 = next_nonnote_insn (temp)) != 0
|
||
&& GET_CODE (temp3) == INSN
|
||
&& REG_NOTES (temp3) == 0
|
||
&& (reallabelprev == temp3
|
||
|| ((temp2 = next_active_insn (temp3)) != 0
|
||
&& simplejump_p (temp2)
|
||
&& JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
|
||
&& (temp1 = single_set (temp)) != 0
|
||
&& (temp2 = SET_DEST (temp1), GET_CODE (temp2) == REG)
|
||
&& GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
|
||
&& (! SMALL_REGISTER_CLASSES
|
||
|| REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
|
||
&& ! side_effects_p (SET_SRC (temp1))
|
||
&& ! may_trap_p (SET_SRC (temp1))
|
||
&& rtx_cost (SET_SRC (temp1), SET) < 10
|
||
&& (temp4 = single_set (temp3)) != 0
|
||
&& rtx_equal_p (SET_DEST (temp4), temp2)
|
||
&& ! side_effects_p (SET_SRC (temp4))
|
||
&& ! may_trap_p (SET_SRC (temp4))
|
||
&& rtx_cost (SET_SRC (temp4), SET) < 10)
|
||
{
|
||
rtx new = gen_reg_rtx (GET_MODE (temp2));
|
||
|
||
if ((temp5 = find_insert_position (insn, temp))
|
||
&& (temp6 = find_insert_position (insn, temp3))
|
||
&& validate_change (temp, &SET_DEST (temp1), new, 0))
|
||
{
|
||
/* Use the earliest of temp5 and temp6. */
|
||
if (temp5 != insn)
|
||
temp6 = temp5;
|
||
next = emit_insn_after (gen_move_insn (temp2, new), insn);
|
||
emit_insn_after_with_line_notes (PATTERN (temp),
|
||
PREV_INSN (temp6), temp);
|
||
emit_insn_after_with_line_notes
|
||
(replace_rtx (PATTERN (temp3), temp2, new),
|
||
PREV_INSN (temp6), temp3);
|
||
delete_insn (temp);
|
||
delete_insn (temp3);
|
||
reallabelprev = prev_active_insn (JUMP_LABEL (insn));
|
||
|
||
if (after_regscan)
|
||
{
|
||
reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
|
||
old_max_reg = max_reg_num ();
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Finally, handle the case where two insns are used to
|
||
compute EXP but a temporary register is used. Here we must
|
||
ensure that the temporary register is not used anywhere else. */
|
||
|
||
if (! reload_completed
|
||
&& after_regscan
|
||
&& this_is_condjump && ! this_is_simplejump
|
||
&& BRANCH_COST >= 4
|
||
&& (temp = next_nonnote_insn (insn)) != 0
|
||
&& GET_CODE (temp) == INSN
|
||
&& REG_NOTES (temp) == 0
|
||
&& (temp3 = next_nonnote_insn (temp)) != 0
|
||
&& GET_CODE (temp3) == INSN
|
||
&& REG_NOTES (temp3) == 0
|
||
&& (reallabelprev == temp3
|
||
|| ((temp2 = next_active_insn (temp3)) != 0
|
||
&& simplejump_p (temp2)
|
||
&& JUMP_LABEL (temp2) == JUMP_LABEL (insn)))
|
||
&& (temp1 = single_set (temp)) != 0
|
||
&& (temp5 = SET_DEST (temp1),
|
||
(GET_CODE (temp5) == REG
|
||
|| (GET_CODE (temp5) == SUBREG
|
||
&& (temp5 = SUBREG_REG (temp5),
|
||
GET_CODE (temp5) == REG))))
|
||
&& REGNO (temp5) >= FIRST_PSEUDO_REGISTER
|
||
&& REGNO_FIRST_UID (REGNO (temp5)) == INSN_UID (temp)
|
||
&& REGNO_LAST_UID (REGNO (temp5)) == INSN_UID (temp3)
|
||
&& ! side_effects_p (SET_SRC (temp1))
|
||
&& ! may_trap_p (SET_SRC (temp1))
|
||
&& rtx_cost (SET_SRC (temp1), SET) < 10
|
||
&& (temp4 = single_set (temp3)) != 0
|
||
&& (temp2 = SET_DEST (temp4), GET_CODE (temp2) == REG)
|
||
&& GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT
|
||
&& (! SMALL_REGISTER_CLASSES
|
||
|| REGNO (temp2) >= FIRST_PSEUDO_REGISTER)
|
||
&& rtx_equal_p (SET_DEST (temp4), temp2)
|
||
&& ! side_effects_p (SET_SRC (temp4))
|
||
&& ! may_trap_p (SET_SRC (temp4))
|
||
&& rtx_cost (SET_SRC (temp4), SET) < 10)
|
||
{
|
||
rtx new = gen_reg_rtx (GET_MODE (temp2));
|
||
|
||
if ((temp5 = find_insert_position (insn, temp))
|
||
&& (temp6 = find_insert_position (insn, temp3))
|
||
&& validate_change (temp3, &SET_DEST (temp4), new, 0))
|
||
{
|
||
/* Use the earliest of temp5 and temp6. */
|
||
if (temp5 != insn)
|
||
temp6 = temp5;
|
||
next = emit_insn_after (gen_move_insn (temp2, new), insn);
|
||
emit_insn_after_with_line_notes (PATTERN (temp),
|
||
PREV_INSN (temp6), temp);
|
||
emit_insn_after_with_line_notes (PATTERN (temp3),
|
||
PREV_INSN (temp6), temp3);
|
||
delete_insn (temp);
|
||
delete_insn (temp3);
|
||
reallabelprev = prev_active_insn (JUMP_LABEL (insn));
|
||
|
||
if (after_regscan)
|
||
{
|
||
reg_scan_update (temp6, NEXT_INSN (next), old_max_reg);
|
||
old_max_reg = max_reg_num ();
|
||
}
|
||
}
|
||
}
|
||
#endif /* HAVE_cc0 */
|
||
|
||
/* Try to use a conditional move (if the target has them), or a
|
||
store-flag insn. The general case is:
|
||
|
||
1) x = a; if (...) x = b; and
|
||
2) if (...) x = b;
|
||
|
||
If the jump would be faster, the machine should not have defined
|
||
the movcc or scc insns!. These cases are often made by the
|
||
previous optimization.
|
||
|
||
The second case is treated as x = x; if (...) x = b;.
|
||
|
||
INSN here is the jump around the store. We set:
|
||
|
||
TEMP to the "x = b;" insn.
|
||
TEMP1 to X.
|
||
TEMP2 to B.
|
||
TEMP3 to A (X in the second case).
|
||
TEMP4 to the condition being tested.
|
||
TEMP5 to the earliest insn used to find the condition. */
|
||
|
||
if (/* We can't do this after reload has completed. */
|
||
! reload_completed
|
||
&& this_is_condjump && ! this_is_simplejump
|
||
/* Set TEMP to the "x = b;" insn. */
|
||
&& (temp = next_nonnote_insn (insn)) != 0
|
||
&& GET_CODE (temp) == INSN
|
||
&& GET_CODE (PATTERN (temp)) == SET
|
||
&& GET_CODE (temp1 = SET_DEST (PATTERN (temp))) == REG
|
||
&& (! SMALL_REGISTER_CLASSES
|
||
|| REGNO (temp1) >= FIRST_PSEUDO_REGISTER)
|
||
&& ! side_effects_p (temp2 = SET_SRC (PATTERN (temp)))
|
||
&& ! may_trap_p (temp2)
|
||
/* Allow either form, but prefer the former if both apply.
|
||
There is no point in using the old value of TEMP1 if
|
||
it is a register, since cse will alias them. It can
|
||
lose if the old value were a hard register since CSE
|
||
won't replace hard registers. Avoid using TEMP3 if
|
||
small register classes and it is a hard register. */
|
||
&& (((temp3 = reg_set_last (temp1, insn)) != 0
|
||
&& ! (SMALL_REGISTER_CLASSES && GET_CODE (temp3) == REG
|
||
&& REGNO (temp3) < FIRST_PSEUDO_REGISTER))
|
||
/* Make the latter case look like x = x; if (...) x = b; */
|
||
|| (temp3 = temp1, 1))
|
||
/* INSN must either branch to the insn after TEMP or the insn
|
||
after TEMP must branch to the same place as INSN. */
|
||
&& (reallabelprev == temp
|
||
|| ((temp4 = next_active_insn (temp)) != 0
|
||
&& simplejump_p (temp4)
|
||
&& JUMP_LABEL (temp4) == JUMP_LABEL (insn)))
|
||
&& (temp4 = get_condition (insn, &temp5)) != 0
|
||
/* We must be comparing objects whose modes imply the size.
|
||
We could handle BLKmode if (1) emit_store_flag could
|
||
and (2) we could find the size reliably. */
|
||
&& GET_MODE (XEXP (temp4, 0)) != BLKmode
|
||
/* Even if branches are cheap, the store_flag optimization
|
||
can win when the operation to be performed can be
|
||
expressed directly. */
|
||
#ifdef HAVE_cc0
|
||
/* If the previous insn sets CC0 and something else, we can't
|
||
do this since we are going to delete that insn. */
|
||
|
||
&& ! ((temp6 = prev_nonnote_insn (insn)) != 0
|
||
&& GET_CODE (temp6) == INSN
|
||
&& (sets_cc0_p (PATTERN (temp6)) == -1
|
||
|| (sets_cc0_p (PATTERN (temp6)) == 1
|
||
&& FIND_REG_INC_NOTE (temp6, NULL_RTX))))
|
||
#endif
|
||
)
|
||
{
|
||
#ifdef HAVE_conditional_move
|
||
/* First try a conditional move. */
|
||
{
|
||
enum rtx_code code = GET_CODE (temp4);
|
||
rtx var = temp1;
|
||
rtx cond0, cond1, aval, bval;
|
||
rtx target;
|
||
|
||
/* Copy the compared variables into cond0 and cond1, so that
|
||
any side effects performed in or after the old comparison,
|
||
will not affect our compare which will come later. */
|
||
/* ??? Is it possible to just use the comparison in the jump
|
||
insn? After all, we're going to delete it. We'd have
|
||
to modify emit_conditional_move to take a comparison rtx
|
||
instead or write a new function. */
|
||
cond0 = gen_reg_rtx (GET_MODE (XEXP (temp4, 0)));
|
||
/* We want the target to be able to simplify comparisons with
|
||
zero (and maybe other constants as well), so don't create
|
||
pseudos for them. There's no need to either. */
|
||
if (GET_CODE (XEXP (temp4, 1)) == CONST_INT
|
||
|| GET_CODE (XEXP (temp4, 1)) == CONST_DOUBLE)
|
||
cond1 = XEXP (temp4, 1);
|
||
else
|
||
cond1 = gen_reg_rtx (GET_MODE (XEXP (temp4, 1)));
|
||
|
||
aval = temp3;
|
||
bval = temp2;
|
||
|
||
start_sequence ();
|
||
target = emit_conditional_move (var, code,
|
||
cond0, cond1, VOIDmode,
|
||
aval, bval, GET_MODE (var),
|
||
(code == LTU || code == GEU
|
||
|| code == LEU || code == GTU));
|
||
|
||
if (target)
|
||
{
|
||
rtx seq1,seq2,last;
|
||
|
||
/* Save the conditional move sequence but don't emit it
|
||
yet. On some machines, like the alpha, it is possible
|
||
that temp5 == insn, so next generate the sequence that
|
||
saves the compared values and then emit both
|
||
sequences ensuring seq1 occurs before seq2. */
|
||
seq2 = get_insns ();
|
||
end_sequence ();
|
||
|
||
/* Now that we can't fail, generate the copy insns that
|
||
preserve the compared values. */
|
||
start_sequence ();
|
||
emit_move_insn (cond0, XEXP (temp4, 0));
|
||
if (cond1 != XEXP (temp4, 1))
|
||
emit_move_insn (cond1, XEXP (temp4, 1));
|
||
seq1 = get_insns ();
|
||
end_sequence ();
|
||
|
||
emit_insns_before (seq1, temp5);
|
||
/* Insert conditional move after insn, to be sure that
|
||
the jump and a possible compare won't be separated */
|
||
last = emit_insns_after (seq2, insn);
|
||
|
||
/* ??? We can also delete the insn that sets X to A.
|
||
Flow will do it too though. */
|
||
delete_insn (temp);
|
||
next = NEXT_INSN (insn);
|
||
delete_jump (insn);
|
||
|
||
if (after_regscan)
|
||
{
|
||
reg_scan_update (seq1, NEXT_INSN (last), old_max_reg);
|
||
old_max_reg = max_reg_num ();
|
||
}
|
||
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
else
|
||
end_sequence ();
|
||
}
|
||
#endif
|
||
|
||
/* That didn't work, try a store-flag insn.
|
||
|
||
We further divide the cases into:
|
||
|
||
1) x = a; if (...) x = b; and either A or B is zero,
|
||
2) if (...) x = 0; and jumps are expensive,
|
||
3) x = a; if (...) x = b; and A and B are constants where all
|
||
the set bits in A are also set in B and jumps are expensive,
|
||
4) x = a; if (...) x = b; and A and B non-zero, and jumps are
|
||
more expensive, and
|
||
5) if (...) x = b; if jumps are even more expensive. */
|
||
|
||
if (GET_MODE_CLASS (GET_MODE (temp1)) == MODE_INT
|
||
&& ((GET_CODE (temp3) == CONST_INT)
|
||
/* Make the latter case look like
|
||
x = x; if (...) x = 0; */
|
||
|| (temp3 = temp1,
|
||
((BRANCH_COST >= 2
|
||
&& temp2 == const0_rtx)
|
||
|| BRANCH_COST >= 3)))
|
||
/* If B is zero, OK; if A is zero, can only do (1) if we
|
||
can reverse the condition. See if (3) applies possibly
|
||
by reversing the condition. Prefer reversing to (4) when
|
||
branches are very expensive. */
|
||
&& (((BRANCH_COST >= 2
|
||
|| STORE_FLAG_VALUE == -1
|
||
|| (STORE_FLAG_VALUE == 1
|
||
/* Check that the mask is a power of two,
|
||
so that it can probably be generated
|
||
with a shift. */
|
||
&& GET_CODE (temp3) == CONST_INT
|
||
&& exact_log2 (INTVAL (temp3)) >= 0))
|
||
&& (reversep = 0, temp2 == const0_rtx))
|
||
|| ((BRANCH_COST >= 2
|
||
|| STORE_FLAG_VALUE == -1
|
||
|| (STORE_FLAG_VALUE == 1
|
||
&& GET_CODE (temp2) == CONST_INT
|
||
&& exact_log2 (INTVAL (temp2)) >= 0))
|
||
&& temp3 == const0_rtx
|
||
&& (reversep = can_reverse_comparison_p (temp4, insn)))
|
||
|| (BRANCH_COST >= 2
|
||
&& GET_CODE (temp2) == CONST_INT
|
||
&& GET_CODE (temp3) == CONST_INT
|
||
&& ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp2)
|
||
|| ((INTVAL (temp2) & INTVAL (temp3)) == INTVAL (temp3)
|
||
&& (reversep = can_reverse_comparison_p (temp4,
|
||
insn)))))
|
||
|| BRANCH_COST >= 3)
|
||
)
|
||
{
|
||
enum rtx_code code = GET_CODE (temp4);
|
||
rtx uval, cval, var = temp1;
|
||
int normalizep;
|
||
rtx target;
|
||
|
||
/* If necessary, reverse the condition. */
|
||
if (reversep)
|
||
code = reverse_condition (code), uval = temp2, cval = temp3;
|
||
else
|
||
uval = temp3, cval = temp2;
|
||
|
||
/* If CVAL is non-zero, normalize to -1. Otherwise, if UVAL
|
||
is the constant 1, it is best to just compute the result
|
||
directly. If UVAL is constant and STORE_FLAG_VALUE
|
||
includes all of its bits, it is best to compute the flag
|
||
value unnormalized and `and' it with UVAL. Otherwise,
|
||
normalize to -1 and `and' with UVAL. */
|
||
normalizep = (cval != const0_rtx ? -1
|
||
: (uval == const1_rtx ? 1
|
||
: (GET_CODE (uval) == CONST_INT
|
||
&& (INTVAL (uval) & ~STORE_FLAG_VALUE) == 0)
|
||
? 0 : -1));
|
||
|
||
/* We will be putting the store-flag insn immediately in
|
||
front of the comparison that was originally being done,
|
||
so we know all the variables in TEMP4 will be valid.
|
||
However, this might be in front of the assignment of
|
||
A to VAR. If it is, it would clobber the store-flag
|
||
we will be emitting.
|
||
|
||
Therefore, emit into a temporary which will be copied to
|
||
VAR immediately after TEMP. */
|
||
|
||
start_sequence ();
|
||
target = emit_store_flag (gen_reg_rtx (GET_MODE (var)), code,
|
||
XEXP (temp4, 0), XEXP (temp4, 1),
|
||
VOIDmode,
|
||
(code == LTU || code == LEU
|
||
|| code == GEU || code == GTU),
|
||
normalizep);
|
||
if (target)
|
||
{
|
||
rtx seq;
|
||
rtx before = insn;
|
||
|
||
seq = get_insns ();
|
||
end_sequence ();
|
||
|
||
/* Put the store-flag insns in front of the first insn
|
||
used to compute the condition to ensure that we
|
||
use the same values of them as the current
|
||
comparison. However, the remainder of the insns we
|
||
generate will be placed directly in front of the
|
||
jump insn, in case any of the pseudos we use
|
||
are modified earlier. */
|
||
|
||
emit_insns_before (seq, temp5);
|
||
|
||
start_sequence ();
|
||
|
||
/* Both CVAL and UVAL are non-zero. */
|
||
if (cval != const0_rtx && uval != const0_rtx)
|
||
{
|
||
rtx tem1, tem2;
|
||
|
||
tem1 = expand_and (uval, target, NULL_RTX);
|
||
if (GET_CODE (cval) == CONST_INT
|
||
&& GET_CODE (uval) == CONST_INT
|
||
&& (INTVAL (cval) & INTVAL (uval)) == INTVAL (cval))
|
||
tem2 = cval;
|
||
else
|
||
{
|
||
tem2 = expand_unop (GET_MODE (var), one_cmpl_optab,
|
||
target, NULL_RTX, 0);
|
||
tem2 = expand_and (cval, tem2,
|
||
(GET_CODE (tem2) == REG
|
||
? tem2 : 0));
|
||
}
|
||
|
||
/* If we usually make new pseudos, do so here. This
|
||
turns out to help machines that have conditional
|
||
move insns. */
|
||
/* ??? Conditional moves have already been handled.
|
||
This may be obsolete. */
|
||
|
||
if (flag_expensive_optimizations)
|
||
target = 0;
|
||
|
||
target = expand_binop (GET_MODE (var), ior_optab,
|
||
tem1, tem2, target,
|
||
1, OPTAB_WIDEN);
|
||
}
|
||
else if (normalizep != 1)
|
||
{
|
||
/* We know that either CVAL or UVAL is zero. If
|
||
UVAL is zero, negate TARGET and `and' with CVAL.
|
||
Otherwise, `and' with UVAL. */
|
||
if (uval == const0_rtx)
|
||
{
|
||
target = expand_unop (GET_MODE (var), one_cmpl_optab,
|
||
target, NULL_RTX, 0);
|
||
uval = cval;
|
||
}
|
||
|
||
target = expand_and (uval, target,
|
||
(GET_CODE (target) == REG
|
||
&& ! preserve_subexpressions_p ()
|
||
? target : NULL_RTX));
|
||
}
|
||
|
||
emit_move_insn (var, target);
|
||
seq = get_insns ();
|
||
end_sequence ();
|
||
#ifdef HAVE_cc0
|
||
/* If INSN uses CC0, we must not separate it from the
|
||
insn that sets cc0. */
|
||
if (reg_mentioned_p (cc0_rtx, PATTERN (before)))
|
||
before = prev_nonnote_insn (before);
|
||
#endif
|
||
emit_insns_before (seq, before);
|
||
|
||
delete_insn (temp);
|
||
next = NEXT_INSN (insn);
|
||
delete_jump (insn);
|
||
|
||
if (after_regscan)
|
||
{
|
||
reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
|
||
old_max_reg = max_reg_num ();
|
||
}
|
||
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
else
|
||
end_sequence ();
|
||
}
|
||
}
|
||
|
||
/* If branches are expensive, convert
|
||
if (foo) bar++; to bar += (foo != 0);
|
||
and similarly for "bar--;"
|
||
|
||
INSN is the conditional branch around the arithmetic. We set:
|
||
|
||
TEMP is the arithmetic insn.
|
||
TEMP1 is the SET doing the arithmetic.
|
||
TEMP2 is the operand being incremented or decremented.
|
||
TEMP3 to the condition being tested.
|
||
TEMP4 to the earliest insn used to find the condition. */
|
||
|
||
if ((BRANCH_COST >= 2
|
||
#ifdef HAVE_incscc
|
||
|| HAVE_incscc
|
||
#endif
|
||
#ifdef HAVE_decscc
|
||
|| HAVE_decscc
|
||
#endif
|
||
)
|
||
&& ! reload_completed
|
||
&& this_is_condjump && ! this_is_simplejump
|
||
&& (temp = next_nonnote_insn (insn)) != 0
|
||
&& (temp1 = single_set (temp)) != 0
|
||
&& (temp2 = SET_DEST (temp1),
|
||
GET_MODE_CLASS (GET_MODE (temp2)) == MODE_INT)
|
||
&& GET_CODE (SET_SRC (temp1)) == PLUS
|
||
&& (XEXP (SET_SRC (temp1), 1) == const1_rtx
|
||
|| XEXP (SET_SRC (temp1), 1) == constm1_rtx)
|
||
&& rtx_equal_p (temp2, XEXP (SET_SRC (temp1), 0))
|
||
&& ! side_effects_p (temp2)
|
||
&& ! may_trap_p (temp2)
|
||
/* INSN must either branch to the insn after TEMP or the insn
|
||
after TEMP must branch to the same place as INSN. */
|
||
&& (reallabelprev == temp
|
||
|| ((temp3 = next_active_insn (temp)) != 0
|
||
&& simplejump_p (temp3)
|
||
&& JUMP_LABEL (temp3) == JUMP_LABEL (insn)))
|
||
&& (temp3 = get_condition (insn, &temp4)) != 0
|
||
/* We must be comparing objects whose modes imply the size.
|
||
We could handle BLKmode if (1) emit_store_flag could
|
||
and (2) we could find the size reliably. */
|
||
&& GET_MODE (XEXP (temp3, 0)) != BLKmode
|
||
&& can_reverse_comparison_p (temp3, insn))
|
||
{
|
||
rtx temp6, target = 0, seq, init_insn = 0, init = temp2;
|
||
enum rtx_code code = reverse_condition (GET_CODE (temp3));
|
||
|
||
start_sequence ();
|
||
|
||
/* It must be the case that TEMP2 is not modified in the range
|
||
[TEMP4, INSN). The one exception we make is if the insn
|
||
before INSN sets TEMP2 to something which is also unchanged
|
||
in that range. In that case, we can move the initialization
|
||
into our sequence. */
|
||
|
||
if ((temp5 = prev_active_insn (insn)) != 0
|
||
&& no_labels_between_p (temp5, insn)
|
||
&& GET_CODE (temp5) == INSN
|
||
&& (temp6 = single_set (temp5)) != 0
|
||
&& rtx_equal_p (temp2, SET_DEST (temp6))
|
||
&& (CONSTANT_P (SET_SRC (temp6))
|
||
|| GET_CODE (SET_SRC (temp6)) == REG
|
||
|| GET_CODE (SET_SRC (temp6)) == SUBREG))
|
||
{
|
||
emit_insn (PATTERN (temp5));
|
||
init_insn = temp5;
|
||
init = SET_SRC (temp6);
|
||
}
|
||
|
||
if (CONSTANT_P (init)
|
||
|| ! reg_set_between_p (init, PREV_INSN (temp4), insn))
|
||
target = emit_store_flag (gen_reg_rtx (GET_MODE (temp2)), code,
|
||
XEXP (temp3, 0), XEXP (temp3, 1),
|
||
VOIDmode,
|
||
(code == LTU || code == LEU
|
||
|| code == GTU || code == GEU), 1);
|
||
|
||
/* If we can do the store-flag, do the addition or
|
||
subtraction. */
|
||
|
||
if (target)
|
||
target = expand_binop (GET_MODE (temp2),
|
||
(XEXP (SET_SRC (temp1), 1) == const1_rtx
|
||
? add_optab : sub_optab),
|
||
temp2, target, temp2, 0, OPTAB_WIDEN);
|
||
|
||
if (target != 0)
|
||
{
|
||
/* Put the result back in temp2 in case it isn't already.
|
||
Then replace the jump, possible a CC0-setting insn in
|
||
front of the jump, and TEMP, with the sequence we have
|
||
made. */
|
||
|
||
if (target != temp2)
|
||
emit_move_insn (temp2, target);
|
||
|
||
seq = get_insns ();
|
||
end_sequence ();
|
||
|
||
emit_insns_before (seq, temp4);
|
||
delete_insn (temp);
|
||
|
||
if (init_insn)
|
||
delete_insn (init_insn);
|
||
|
||
next = NEXT_INSN (insn);
|
||
#ifdef HAVE_cc0
|
||
delete_insn (prev_nonnote_insn (insn));
|
||
#endif
|
||
delete_insn (insn);
|
||
|
||
if (after_regscan)
|
||
{
|
||
reg_scan_update (seq, NEXT_INSN (next), old_max_reg);
|
||
old_max_reg = max_reg_num ();
|
||
}
|
||
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
else
|
||
end_sequence ();
|
||
}
|
||
|
||
/* Simplify if (...) x = 1; else {...} if (x) ...
|
||
We recognize this case scanning backwards as well.
|
||
|
||
TEMP is the assignment to x;
|
||
TEMP1 is the label at the head of the second if. */
|
||
/* ?? This should call get_condition to find the values being
|
||
compared, instead of looking for a COMPARE insn when HAVE_cc0
|
||
is not defined. This would allow it to work on the m88k. */
|
||
/* ?? This optimization is only safe before cse is run if HAVE_cc0
|
||
is not defined and the condition is tested by a separate compare
|
||
insn. This is because the code below assumes that the result
|
||
of the compare dies in the following branch.
|
||
|
||
Not only that, but there might be other insns between the
|
||
compare and branch whose results are live. Those insns need
|
||
to be executed.
|
||
|
||
A way to fix this is to move the insns at JUMP_LABEL (insn)
|
||
to before INSN. If we are running before flow, they will
|
||
be deleted if they aren't needed. But this doesn't work
|
||
well after flow.
|
||
|
||
This is really a special-case of jump threading, anyway. The
|
||
right thing to do is to replace this and jump threading with
|
||
much simpler code in cse.
|
||
|
||
This code has been turned off in the non-cc0 case in the
|
||
meantime. */
|
||
|
||
#ifdef HAVE_cc0
|
||
else if (this_is_simplejump
|
||
/* Safe to skip USE and CLOBBER insns here
|
||
since they will not be deleted. */
|
||
&& (temp = prev_active_insn (insn))
|
||
&& no_labels_between_p (temp, insn)
|
||
&& GET_CODE (temp) == INSN
|
||
&& GET_CODE (PATTERN (temp)) == SET
|
||
&& GET_CODE (SET_DEST (PATTERN (temp))) == REG
|
||
&& CONSTANT_P (SET_SRC (PATTERN (temp)))
|
||
&& (temp1 = next_active_insn (JUMP_LABEL (insn)))
|
||
/* If we find that the next value tested is `x'
|
||
(TEMP1 is the insn where this happens), win. */
|
||
&& GET_CODE (temp1) == INSN
|
||
&& GET_CODE (PATTERN (temp1)) == SET
|
||
#ifdef HAVE_cc0
|
||
/* Does temp1 `tst' the value of x? */
|
||
&& SET_SRC (PATTERN (temp1)) == SET_DEST (PATTERN (temp))
|
||
&& SET_DEST (PATTERN (temp1)) == cc0_rtx
|
||
&& (temp1 = next_nonnote_insn (temp1))
|
||
#else
|
||
/* Does temp1 compare the value of x against zero? */
|
||
&& GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
|
||
&& XEXP (SET_SRC (PATTERN (temp1)), 1) == const0_rtx
|
||
&& (XEXP (SET_SRC (PATTERN (temp1)), 0)
|
||
== SET_DEST (PATTERN (temp)))
|
||
&& GET_CODE (SET_DEST (PATTERN (temp1))) == REG
|
||
&& (temp1 = find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
|
||
#endif
|
||
&& condjump_p (temp1))
|
||
{
|
||
/* Get the if_then_else from the condjump. */
|
||
rtx choice = SET_SRC (PATTERN (temp1));
|
||
if (GET_CODE (choice) == IF_THEN_ELSE)
|
||
{
|
||
enum rtx_code code = GET_CODE (XEXP (choice, 0));
|
||
rtx val = SET_SRC (PATTERN (temp));
|
||
rtx cond
|
||
= simplify_relational_operation (code, GET_MODE (SET_DEST (PATTERN (temp))),
|
||
val, const0_rtx);
|
||
rtx ultimate;
|
||
|
||
if (cond == const_true_rtx)
|
||
ultimate = XEXP (choice, 1);
|
||
else if (cond == const0_rtx)
|
||
ultimate = XEXP (choice, 2);
|
||
else
|
||
ultimate = 0;
|
||
|
||
if (ultimate == pc_rtx)
|
||
ultimate = get_label_after (temp1);
|
||
else if (ultimate && GET_CODE (ultimate) != RETURN)
|
||
ultimate = XEXP (ultimate, 0);
|
||
|
||
if (ultimate && JUMP_LABEL(insn) != ultimate)
|
||
changed |= redirect_jump (insn, ultimate);
|
||
}
|
||
}
|
||
#endif
|
||
|
||
#if 0
|
||
/* @@ This needs a bit of work before it will be right.
|
||
|
||
Any type of comparison can be accepted for the first and
|
||
second compare. When rewriting the first jump, we must
|
||
compute the what conditions can reach label3, and use the
|
||
appropriate code. We can not simply reverse/swap the code
|
||
of the first jump. In some cases, the second jump must be
|
||
rewritten also.
|
||
|
||
For example,
|
||
< == converts to > ==
|
||
< != converts to == >
|
||
etc.
|
||
|
||
If the code is written to only accept an '==' test for the second
|
||
compare, then all that needs to be done is to swap the condition
|
||
of the first branch.
|
||
|
||
It is questionable whether we want this optimization anyways,
|
||
since if the user wrote code like this because he/she knew that
|
||
the jump to label1 is taken most of the time, then rewriting
|
||
this gives slower code. */
|
||
/* @@ This should call get_condition to find the values being
|
||
compared, instead of looking for a COMPARE insn when HAVE_cc0
|
||
is not defined. This would allow it to work on the m88k. */
|
||
/* @@ This optimization is only safe before cse is run if HAVE_cc0
|
||
is not defined and the condition is tested by a separate compare
|
||
insn. This is because the code below assumes that the result
|
||
of the compare dies in the following branch. */
|
||
|
||
/* Simplify test a ~= b
|
||
condjump label1;
|
||
test a == b
|
||
condjump label2;
|
||
jump label3;
|
||
label1:
|
||
|
||
rewriting as
|
||
test a ~~= b
|
||
condjump label3
|
||
test a == b
|
||
condjump label2
|
||
label1:
|
||
|
||
where ~= is an inequality, e.g. >, and ~~= is the swapped
|
||
inequality, e.g. <.
|
||
|
||
We recognize this case scanning backwards.
|
||
|
||
TEMP is the conditional jump to `label2';
|
||
TEMP1 is the test for `a == b';
|
||
TEMP2 is the conditional jump to `label1';
|
||
TEMP3 is the test for `a ~= b'. */
|
||
else if (this_is_simplejump
|
||
&& (temp = prev_active_insn (insn))
|
||
&& no_labels_between_p (temp, insn)
|
||
&& condjump_p (temp)
|
||
&& (temp1 = prev_active_insn (temp))
|
||
&& no_labels_between_p (temp1, temp)
|
||
&& GET_CODE (temp1) == INSN
|
||
&& GET_CODE (PATTERN (temp1)) == SET
|
||
#ifdef HAVE_cc0
|
||
&& sets_cc0_p (PATTERN (temp1)) == 1
|
||
#else
|
||
&& GET_CODE (SET_SRC (PATTERN (temp1))) == COMPARE
|
||
&& GET_CODE (SET_DEST (PATTERN (temp1))) == REG
|
||
&& (temp == find_next_ref (SET_DEST (PATTERN (temp1)), temp1))
|
||
#endif
|
||
&& (temp2 = prev_active_insn (temp1))
|
||
&& no_labels_between_p (temp2, temp1)
|
||
&& condjump_p (temp2)
|
||
&& JUMP_LABEL (temp2) == next_nonnote_insn (NEXT_INSN (insn))
|
||
&& (temp3 = prev_active_insn (temp2))
|
||
&& no_labels_between_p (temp3, temp2)
|
||
&& GET_CODE (PATTERN (temp3)) == SET
|
||
&& rtx_equal_p (SET_DEST (PATTERN (temp3)),
|
||
SET_DEST (PATTERN (temp1)))
|
||
&& rtx_equal_p (SET_SRC (PATTERN (temp1)),
|
||
SET_SRC (PATTERN (temp3)))
|
||
&& ! inequality_comparisons_p (PATTERN (temp))
|
||
&& inequality_comparisons_p (PATTERN (temp2)))
|
||
{
|
||
rtx fallthrough_label = JUMP_LABEL (temp2);
|
||
|
||
++LABEL_NUSES (fallthrough_label);
|
||
if (swap_jump (temp2, JUMP_LABEL (insn)))
|
||
{
|
||
delete_insn (insn);
|
||
changed = 1;
|
||
}
|
||
|
||
if (--LABEL_NUSES (fallthrough_label) == 0)
|
||
delete_insn (fallthrough_label);
|
||
}
|
||
#endif
|
||
/* Simplify if (...) {... x = 1;} if (x) ...
|
||
|
||
We recognize this case backwards.
|
||
|
||
TEMP is the test of `x';
|
||
TEMP1 is the assignment to `x' at the end of the
|
||
previous statement. */
|
||
/* @@ This should call get_condition to find the values being
|
||
compared, instead of looking for a COMPARE insn when HAVE_cc0
|
||
is not defined. This would allow it to work on the m88k. */
|
||
/* @@ This optimization is only safe before cse is run if HAVE_cc0
|
||
is not defined and the condition is tested by a separate compare
|
||
insn. This is because the code below assumes that the result
|
||
of the compare dies in the following branch. */
|
||
|
||
/* ??? This has to be turned off. The problem is that the
|
||
unconditional jump might indirectly end up branching to the
|
||
label between TEMP1 and TEMP. We can't detect this, in general,
|
||
since it may become a jump to there after further optimizations.
|
||
If that jump is done, it will be deleted, so we will retry
|
||
this optimization in the next pass, thus an infinite loop.
|
||
|
||
The present code prevents this by putting the jump after the
|
||
label, but this is not logically correct. */
|
||
#if 0
|
||
else if (this_is_condjump
|
||
/* Safe to skip USE and CLOBBER insns here
|
||
since they will not be deleted. */
|
||
&& (temp = prev_active_insn (insn))
|
||
&& no_labels_between_p (temp, insn)
|
||
&& GET_CODE (temp) == INSN
|
||
&& GET_CODE (PATTERN (temp)) == SET
|
||
#ifdef HAVE_cc0
|
||
&& sets_cc0_p (PATTERN (temp)) == 1
|
||
&& GET_CODE (SET_SRC (PATTERN (temp))) == REG
|
||
#else
|
||
/* Temp must be a compare insn, we can not accept a register
|
||
to register move here, since it may not be simply a
|
||
tst insn. */
|
||
&& GET_CODE (SET_SRC (PATTERN (temp))) == COMPARE
|
||
&& XEXP (SET_SRC (PATTERN (temp)), 1) == const0_rtx
|
||
&& GET_CODE (XEXP (SET_SRC (PATTERN (temp)), 0)) == REG
|
||
&& GET_CODE (SET_DEST (PATTERN (temp))) == REG
|
||
&& insn == find_next_ref (SET_DEST (PATTERN (temp)), temp)
|
||
#endif
|
||
/* May skip USE or CLOBBER insns here
|
||
for checking for opportunity, since we
|
||
take care of them later. */
|
||
&& (temp1 = prev_active_insn (temp))
|
||
&& GET_CODE (temp1) == INSN
|
||
&& GET_CODE (PATTERN (temp1)) == SET
|
||
#ifdef HAVE_cc0
|
||
&& SET_SRC (PATTERN (temp)) == SET_DEST (PATTERN (temp1))
|
||
#else
|
||
&& (XEXP (SET_SRC (PATTERN (temp)), 0)
|
||
== SET_DEST (PATTERN (temp1)))
|
||
#endif
|
||
&& CONSTANT_P (SET_SRC (PATTERN (temp1)))
|
||
/* If this isn't true, cse will do the job. */
|
||
&& ! no_labels_between_p (temp1, temp))
|
||
{
|
||
/* Get the if_then_else from the condjump. */
|
||
rtx choice = SET_SRC (PATTERN (insn));
|
||
if (GET_CODE (choice) == IF_THEN_ELSE
|
||
&& (GET_CODE (XEXP (choice, 0)) == EQ
|
||
|| GET_CODE (XEXP (choice, 0)) == NE))
|
||
{
|
||
int want_nonzero = (GET_CODE (XEXP (choice, 0)) == NE);
|
||
rtx last_insn;
|
||
rtx ultimate;
|
||
rtx p;
|
||
|
||
/* Get the place that condjump will jump to
|
||
if it is reached from here. */
|
||
if ((SET_SRC (PATTERN (temp1)) != const0_rtx)
|
||
== want_nonzero)
|
||
ultimate = XEXP (choice, 1);
|
||
else
|
||
ultimate = XEXP (choice, 2);
|
||
/* Get it as a CODE_LABEL. */
|
||
if (ultimate == pc_rtx)
|
||
ultimate = get_label_after (insn);
|
||
else
|
||
/* Get the label out of the LABEL_REF. */
|
||
ultimate = XEXP (ultimate, 0);
|
||
|
||
/* Insert the jump immediately before TEMP, specifically
|
||
after the label that is between TEMP1 and TEMP. */
|
||
last_insn = PREV_INSN (temp);
|
||
|
||
/* If we would be branching to the next insn, the jump
|
||
would immediately be deleted and the re-inserted in
|
||
a subsequent pass over the code. So don't do anything
|
||
in that case. */
|
||
if (next_active_insn (last_insn)
|
||
!= next_active_insn (ultimate))
|
||
{
|
||
emit_barrier_after (last_insn);
|
||
p = emit_jump_insn_after (gen_jump (ultimate),
|
||
last_insn);
|
||
JUMP_LABEL (p) = ultimate;
|
||
++LABEL_NUSES (ultimate);
|
||
if (INSN_UID (ultimate) < max_jump_chain
|
||
&& INSN_CODE (p) < max_jump_chain)
|
||
{
|
||
jump_chain[INSN_UID (p)]
|
||
= jump_chain[INSN_UID (ultimate)];
|
||
jump_chain[INSN_UID (ultimate)] = p;
|
||
}
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
}
|
||
}
|
||
#endif
|
||
/* Detect a conditional jump going to the same place
|
||
as an immediately following unconditional jump. */
|
||
else if (this_is_condjump
|
||
&& (temp = next_active_insn (insn)) != 0
|
||
&& simplejump_p (temp)
|
||
&& (next_active_insn (JUMP_LABEL (insn))
|
||
== next_active_insn (JUMP_LABEL (temp))))
|
||
{
|
||
rtx tem = temp;
|
||
|
||
/* ??? Optional. Disables some optimizations, but makes
|
||
gcov output more accurate with -O. */
|
||
if (flag_test_coverage && !reload_completed)
|
||
for (tem = insn; tem != temp; tem = NEXT_INSN (tem))
|
||
if (GET_CODE (tem) == NOTE && NOTE_LINE_NUMBER (tem) > 0)
|
||
break;
|
||
|
||
if (tem == temp)
|
||
{
|
||
delete_jump (insn);
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
}
|
||
#ifdef HAVE_trap
|
||
/* Detect a conditional jump jumping over an unconditional trap. */
|
||
else if (HAVE_trap
|
||
&& this_is_condjump && ! this_is_simplejump
|
||
&& reallabelprev != 0
|
||
&& GET_CODE (reallabelprev) == INSN
|
||
&& GET_CODE (PATTERN (reallabelprev)) == TRAP_IF
|
||
&& TRAP_CONDITION (PATTERN (reallabelprev)) == const_true_rtx
|
||
&& prev_active_insn (reallabelprev) == insn
|
||
&& no_labels_between_p (insn, reallabelprev)
|
||
&& (temp2 = get_condition (insn, &temp4))
|
||
&& can_reverse_comparison_p (temp2, insn))
|
||
{
|
||
rtx new = gen_cond_trap (reverse_condition (GET_CODE (temp2)),
|
||
XEXP (temp2, 0), XEXP (temp2, 1),
|
||
TRAP_CODE (PATTERN (reallabelprev)));
|
||
|
||
if (new)
|
||
{
|
||
emit_insn_before (new, temp4);
|
||
delete_insn (reallabelprev);
|
||
delete_jump (insn);
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
}
|
||
/* Detect a jump jumping to an unconditional trap. */
|
||
else if (HAVE_trap && this_is_condjump
|
||
&& (temp = next_active_insn (JUMP_LABEL (insn)))
|
||
&& GET_CODE (temp) == INSN
|
||
&& GET_CODE (PATTERN (temp)) == TRAP_IF
|
||
&& (this_is_simplejump
|
||
|| (temp2 = get_condition (insn, &temp4))))
|
||
{
|
||
rtx tc = TRAP_CONDITION (PATTERN (temp));
|
||
|
||
if (tc == const_true_rtx
|
||
|| (! this_is_simplejump && rtx_equal_p (temp2, tc)))
|
||
{
|
||
rtx new;
|
||
/* Replace an unconditional jump to a trap with a trap. */
|
||
if (this_is_simplejump)
|
||
{
|
||
emit_barrier_after (emit_insn_before (gen_trap (), insn));
|
||
delete_jump (insn);
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
new = gen_cond_trap (GET_CODE (temp2), XEXP (temp2, 0),
|
||
XEXP (temp2, 1),
|
||
TRAP_CODE (PATTERN (temp)));
|
||
if (new)
|
||
{
|
||
emit_insn_before (new, temp4);
|
||
delete_jump (insn);
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
}
|
||
/* If the trap condition and jump condition are mutually
|
||
exclusive, redirect the jump to the following insn. */
|
||
else if (GET_RTX_CLASS (GET_CODE (tc)) == '<'
|
||
&& ! this_is_simplejump
|
||
&& swap_condition (GET_CODE (temp2)) == GET_CODE (tc)
|
||
&& rtx_equal_p (XEXP (tc, 0), XEXP (temp2, 0))
|
||
&& rtx_equal_p (XEXP (tc, 1), XEXP (temp2, 1))
|
||
&& redirect_jump (insn, get_label_after (temp)))
|
||
{
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
}
|
||
#endif
|
||
|
||
/* Detect a conditional jump jumping over an unconditional jump. */
|
||
|
||
else if ((this_is_condjump || this_is_condjump_in_parallel)
|
||
&& ! this_is_simplejump
|
||
&& reallabelprev != 0
|
||
&& GET_CODE (reallabelprev) == JUMP_INSN
|
||
&& prev_active_insn (reallabelprev) == insn
|
||
&& no_labels_between_p (insn, reallabelprev)
|
||
&& simplejump_p (reallabelprev))
|
||
{
|
||
/* When we invert the unconditional jump, we will be
|
||
decrementing the usage count of its old label.
|
||
Make sure that we don't delete it now because that
|
||
might cause the following code to be deleted. */
|
||
rtx prev_uses = prev_nonnote_insn (reallabelprev);
|
||
rtx prev_label = JUMP_LABEL (insn);
|
||
|
||
if (prev_label)
|
||
++LABEL_NUSES (prev_label);
|
||
|
||
if (invert_jump (insn, JUMP_LABEL (reallabelprev)))
|
||
{
|
||
/* It is very likely that if there are USE insns before
|
||
this jump, they hold REG_DEAD notes. These REG_DEAD
|
||
notes are no longer valid due to this optimization,
|
||
and will cause the life-analysis that following passes
|
||
(notably delayed-branch scheduling) to think that
|
||
these registers are dead when they are not.
|
||
|
||
To prevent this trouble, we just remove the USE insns
|
||
from the insn chain. */
|
||
|
||
while (prev_uses && GET_CODE (prev_uses) == INSN
|
||
&& GET_CODE (PATTERN (prev_uses)) == USE)
|
||
{
|
||
rtx useless = prev_uses;
|
||
prev_uses = prev_nonnote_insn (prev_uses);
|
||
delete_insn (useless);
|
||
}
|
||
|
||
delete_insn (reallabelprev);
|
||
next = insn;
|
||
changed = 1;
|
||
}
|
||
|
||
/* We can now safely delete the label if it is unreferenced
|
||
since the delete_insn above has deleted the BARRIER. */
|
||
if (prev_label && --LABEL_NUSES (prev_label) == 0)
|
||
delete_insn (prev_label);
|
||
continue;
|
||
}
|
||
else
|
||
{
|
||
/* Detect a jump to a jump. */
|
||
|
||
nlabel = follow_jumps (JUMP_LABEL (insn));
|
||
if (nlabel != JUMP_LABEL (insn)
|
||
&& redirect_jump (insn, nlabel))
|
||
{
|
||
changed = 1;
|
||
next = insn;
|
||
}
|
||
|
||
/* Look for if (foo) bar; else break; */
|
||
/* The insns look like this:
|
||
insn = condjump label1;
|
||
...range1 (some insns)...
|
||
jump label2;
|
||
label1:
|
||
...range2 (some insns)...
|
||
jump somewhere unconditionally
|
||
label2: */
|
||
{
|
||
rtx label1 = next_label (insn);
|
||
rtx range1end = label1 ? prev_active_insn (label1) : 0;
|
||
/* Don't do this optimization on the first round, so that
|
||
jump-around-a-jump gets simplified before we ask here
|
||
whether a jump is unconditional.
|
||
|
||
Also don't do it when we are called after reload since
|
||
it will confuse reorg. */
|
||
if (! first
|
||
&& (reload_completed ? ! flag_delayed_branch : 1)
|
||
/* Make sure INSN is something we can invert. */
|
||
&& condjump_p (insn)
|
||
&& label1 != 0
|
||
&& JUMP_LABEL (insn) == label1
|
||
&& LABEL_NUSES (label1) == 1
|
||
&& GET_CODE (range1end) == JUMP_INSN
|
||
&& simplejump_p (range1end))
|
||
{
|
||
rtx label2 = next_label (label1);
|
||
rtx range2end = label2 ? prev_active_insn (label2) : 0;
|
||
if (range1end != range2end
|
||
&& JUMP_LABEL (range1end) == label2
|
||
&& GET_CODE (range2end) == JUMP_INSN
|
||
&& GET_CODE (NEXT_INSN (range2end)) == BARRIER
|
||
/* Invert the jump condition, so we
|
||
still execute the same insns in each case. */
|
||
&& invert_jump (insn, label1))
|
||
{
|
||
rtx range1beg = next_active_insn (insn);
|
||
rtx range2beg = next_active_insn (label1);
|
||
rtx range1after, range2after;
|
||
rtx range1before, range2before;
|
||
rtx rangenext;
|
||
|
||
/* Include in each range any notes before it, to be
|
||
sure that we get the line number note if any, even
|
||
if there are other notes here. */
|
||
while (PREV_INSN (range1beg)
|
||
&& GET_CODE (PREV_INSN (range1beg)) == NOTE)
|
||
range1beg = PREV_INSN (range1beg);
|
||
|
||
while (PREV_INSN (range2beg)
|
||
&& GET_CODE (PREV_INSN (range2beg)) == NOTE)
|
||
range2beg = PREV_INSN (range2beg);
|
||
|
||
/* Don't move NOTEs for blocks or loops; shift them
|
||
outside the ranges, where they'll stay put. */
|
||
range1beg = squeeze_notes (range1beg, range1end);
|
||
range2beg = squeeze_notes (range2beg, range2end);
|
||
|
||
/* Get current surrounds of the 2 ranges. */
|
||
range1before = PREV_INSN (range1beg);
|
||
range2before = PREV_INSN (range2beg);
|
||
range1after = NEXT_INSN (range1end);
|
||
range2after = NEXT_INSN (range2end);
|
||
|
||
/* Splice range2 where range1 was. */
|
||
NEXT_INSN (range1before) = range2beg;
|
||
PREV_INSN (range2beg) = range1before;
|
||
NEXT_INSN (range2end) = range1after;
|
||
PREV_INSN (range1after) = range2end;
|
||
/* Splice range1 where range2 was. */
|
||
NEXT_INSN (range2before) = range1beg;
|
||
PREV_INSN (range1beg) = range2before;
|
||
NEXT_INSN (range1end) = range2after;
|
||
PREV_INSN (range2after) = range1end;
|
||
|
||
/* Check for a loop end note between the end of
|
||
range2, and the next code label. If there is one,
|
||
then what we have really seen is
|
||
if (foo) break; end_of_loop;
|
||
and moved the break sequence outside the loop.
|
||
We must move the LOOP_END note to where the
|
||
loop really ends now, or we will confuse loop
|
||
optimization. Stop if we find a LOOP_BEG note
|
||
first, since we don't want to move the LOOP_END
|
||
note in that case. */
|
||
for (;range2after != label2; range2after = rangenext)
|
||
{
|
||
rangenext = NEXT_INSN (range2after);
|
||
if (GET_CODE (range2after) == NOTE)
|
||
{
|
||
if (NOTE_LINE_NUMBER (range2after)
|
||
== NOTE_INSN_LOOP_END)
|
||
{
|
||
NEXT_INSN (PREV_INSN (range2after))
|
||
= rangenext;
|
||
PREV_INSN (rangenext)
|
||
= PREV_INSN (range2after);
|
||
PREV_INSN (range2after)
|
||
= PREV_INSN (range1beg);
|
||
NEXT_INSN (range2after) = range1beg;
|
||
NEXT_INSN (PREV_INSN (range1beg))
|
||
= range2after;
|
||
PREV_INSN (range1beg) = range2after;
|
||
}
|
||
else if (NOTE_LINE_NUMBER (range2after)
|
||
== NOTE_INSN_LOOP_BEG)
|
||
break;
|
||
}
|
||
}
|
||
changed = 1;
|
||
continue;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Now that the jump has been tensioned,
|
||
try cross jumping: check for identical code
|
||
before the jump and before its target label. */
|
||
|
||
/* First, cross jumping of conditional jumps: */
|
||
|
||
if (cross_jump && condjump_p (insn))
|
||
{
|
||
rtx newjpos, newlpos;
|
||
rtx x = prev_real_insn (JUMP_LABEL (insn));
|
||
|
||
/* A conditional jump may be crossjumped
|
||
only if the place it jumps to follows
|
||
an opposing jump that comes back here. */
|
||
|
||
if (x != 0 && ! jump_back_p (x, insn))
|
||
/* We have no opposing jump;
|
||
cannot cross jump this insn. */
|
||
x = 0;
|
||
|
||
newjpos = 0;
|
||
/* TARGET is nonzero if it is ok to cross jump
|
||
to code before TARGET. If so, see if matches. */
|
||
if (x != 0)
|
||
find_cross_jump (insn, x, 2,
|
||
&newjpos, &newlpos);
|
||
|
||
if (newjpos != 0)
|
||
{
|
||
do_cross_jump (insn, newjpos, newlpos);
|
||
/* Make the old conditional jump
|
||
into an unconditional one. */
|
||
SET_SRC (PATTERN (insn))
|
||
= gen_rtx_LABEL_REF (VOIDmode, JUMP_LABEL (insn));
|
||
INSN_CODE (insn) = -1;
|
||
emit_barrier_after (insn);
|
||
/* Add to jump_chain unless this is a new label
|
||
whose UID is too large. */
|
||
if (INSN_UID (JUMP_LABEL (insn)) < max_jump_chain)
|
||
{
|
||
jump_chain[INSN_UID (insn)]
|
||
= jump_chain[INSN_UID (JUMP_LABEL (insn))];
|
||
jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
|
||
}
|
||
changed = 1;
|
||
next = insn;
|
||
}
|
||
}
|
||
|
||
/* Cross jumping of unconditional jumps:
|
||
a few differences. */
|
||
|
||
if (cross_jump && simplejump_p (insn))
|
||
{
|
||
rtx newjpos, newlpos;
|
||
rtx target;
|
||
|
||
newjpos = 0;
|
||
|
||
/* TARGET is nonzero if it is ok to cross jump
|
||
to code before TARGET. If so, see if matches. */
|
||
find_cross_jump (insn, JUMP_LABEL (insn), 1,
|
||
&newjpos, &newlpos);
|
||
|
||
/* If cannot cross jump to code before the label,
|
||
see if we can cross jump to another jump to
|
||
the same label. */
|
||
/* Try each other jump to this label. */
|
||
if (INSN_UID (JUMP_LABEL (insn)) < max_uid)
|
||
for (target = jump_chain[INSN_UID (JUMP_LABEL (insn))];
|
||
target != 0 && newjpos == 0;
|
||
target = jump_chain[INSN_UID (target)])
|
||
if (target != insn
|
||
&& JUMP_LABEL (target) == JUMP_LABEL (insn)
|
||
/* Ignore TARGET if it's deleted. */
|
||
&& ! INSN_DELETED_P (target))
|
||
find_cross_jump (insn, target, 2,
|
||
&newjpos, &newlpos);
|
||
|
||
if (newjpos != 0)
|
||
{
|
||
do_cross_jump (insn, newjpos, newlpos);
|
||
changed = 1;
|
||
next = insn;
|
||
}
|
||
}
|
||
|
||
/* This code was dead in the previous jump.c! */
|
||
if (cross_jump && GET_CODE (PATTERN (insn)) == RETURN)
|
||
{
|
||
/* Return insns all "jump to the same place"
|
||
so we can cross-jump between any two of them. */
|
||
|
||
rtx newjpos, newlpos, target;
|
||
|
||
newjpos = 0;
|
||
|
||
/* If cannot cross jump to code before the label,
|
||
see if we can cross jump to another jump to
|
||
the same label. */
|
||
/* Try each other jump to this label. */
|
||
for (target = jump_chain[0];
|
||
target != 0 && newjpos == 0;
|
||
target = jump_chain[INSN_UID (target)])
|
||
if (target != insn
|
||
&& ! INSN_DELETED_P (target)
|
||
&& GET_CODE (PATTERN (target)) == RETURN)
|
||
find_cross_jump (insn, target, 2,
|
||
&newjpos, &newlpos);
|
||
|
||
if (newjpos != 0)
|
||
{
|
||
do_cross_jump (insn, newjpos, newlpos);
|
||
changed = 1;
|
||
next = insn;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
first = 0;
|
||
}
|
||
|
||
/* Delete extraneous line number notes.
|
||
Note that two consecutive notes for different lines are not really
|
||
extraneous. There should be some indication where that line belonged,
|
||
even if it became empty. */
|
||
|
||
{
|
||
rtx last_note = 0;
|
||
|
||
for (insn = f; insn; insn = NEXT_INSN (insn))
|
||
if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) >= 0)
|
||
{
|
||
/* Delete this note if it is identical to previous note. */
|
||
if (last_note
|
||
&& NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last_note)
|
||
&& NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last_note))
|
||
{
|
||
delete_insn (insn);
|
||
continue;
|
||
}
|
||
|
||
last_note = insn;
|
||
}
|
||
}
|
||
|
||
#ifdef HAVE_return
|
||
if (HAVE_return)
|
||
{
|
||
/* If we fall through to the epilogue, see if we can insert a RETURN insn
|
||
in front of it. If the machine allows it at this point (we might be
|
||
after reload for a leaf routine), it will improve optimization for it
|
||
to be there. We do this both here and at the start of this pass since
|
||
the RETURN might have been deleted by some of our optimizations. */
|
||
insn = get_last_insn ();
|
||
while (insn && GET_CODE (insn) == NOTE)
|
||
insn = PREV_INSN (insn);
|
||
|
||
if (insn && GET_CODE (insn) != BARRIER)
|
||
{
|
||
emit_jump_insn (gen_return ());
|
||
emit_barrier ();
|
||
}
|
||
}
|
||
#endif
|
||
|
||
/* CAN_REACH_END is persistent for each function. Once set it should
|
||
not be cleared. This is especially true for the case where we
|
||
delete the NOTE_FUNCTION_END note. CAN_REACH_END is cleared by
|
||
the front-end before compiling each function. */
|
||
if (calculate_can_reach_end (last_insn, 0, 1))
|
||
can_reach_end = 1;
|
||
|
||
/* Show JUMP_CHAIN no longer valid. */
|
||
jump_chain = 0;
|
||
}
|
||
|
||
/* Initialize LABEL_NUSES and JUMP_LABEL fields. Delete any REG_LABEL
|
||
notes whose labels don't occur in the insn any more. Returns the
|
||
largest INSN_UID found. */
|
||
static int
|
||
init_label_info (f)
|
||
rtx f;
|
||
{
|
||
int largest_uid = 0;
|
||
rtx insn;
|
||
|
||
for (insn = f; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
if (GET_CODE (insn) == CODE_LABEL)
|
||
LABEL_NUSES (insn) = (LABEL_PRESERVE_P (insn) != 0);
|
||
else if (GET_CODE (insn) == JUMP_INSN)
|
||
JUMP_LABEL (insn) = 0;
|
||
else if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
|
||
{
|
||
rtx note, next;
|
||
|
||
for (note = REG_NOTES (insn); note; note = next)
|
||
{
|
||
next = XEXP (note, 1);
|
||
if (REG_NOTE_KIND (note) == REG_LABEL
|
||
&& ! reg_mentioned_p (XEXP (note, 0), PATTERN (insn)))
|
||
remove_note (insn, note);
|
||
}
|
||
}
|
||
if (INSN_UID (insn) > largest_uid)
|
||
largest_uid = INSN_UID (insn);
|
||
}
|
||
|
||
return largest_uid;
|
||
}
|
||
|
||
/* Delete insns following barriers, up to next label.
|
||
|
||
Also delete no-op jumps created by gcse. */
|
||
static void
|
||
delete_barrier_successors (f)
|
||
rtx f;
|
||
{
|
||
rtx insn;
|
||
|
||
for (insn = f; insn;)
|
||
{
|
||
if (GET_CODE (insn) == BARRIER)
|
||
{
|
||
insn = NEXT_INSN (insn);
|
||
while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
|
||
{
|
||
if (GET_CODE (insn) == NOTE
|
||
&& NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
|
||
insn = NEXT_INSN (insn);
|
||
else
|
||
insn = delete_insn (insn);
|
||
}
|
||
/* INSN is now the code_label. */
|
||
}
|
||
/* Also remove (set (pc) (pc)) insns which can be created by
|
||
gcse. We eliminate such insns now to avoid having them
|
||
cause problems later. */
|
||
else if (GET_CODE (insn) == JUMP_INSN
|
||
&& SET_SRC (PATTERN (insn)) == pc_rtx
|
||
&& SET_DEST (PATTERN (insn)) == pc_rtx)
|
||
insn = delete_insn (insn);
|
||
|
||
else
|
||
insn = NEXT_INSN (insn);
|
||
}
|
||
}
|
||
|
||
/* Mark the label each jump jumps to.
|
||
Combine consecutive labels, and count uses of labels.
|
||
|
||
For each label, make a chain (using `jump_chain')
|
||
of all the *unconditional* jumps that jump to it;
|
||
also make a chain of all returns.
|
||
|
||
CROSS_JUMP indicates whether we are doing cross jumping
|
||
and if we are whether we will be paying attention to
|
||
death notes or not. */
|
||
|
||
static void
|
||
mark_all_labels (f, cross_jump)
|
||
rtx f;
|
||
int cross_jump;
|
||
{
|
||
rtx insn;
|
||
|
||
for (insn = f; insn; insn = NEXT_INSN (insn))
|
||
if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
|
||
{
|
||
mark_jump_label (PATTERN (insn), insn, cross_jump);
|
||
if (! INSN_DELETED_P (insn) && GET_CODE (insn) == JUMP_INSN)
|
||
{
|
||
if (JUMP_LABEL (insn) != 0 && simplejump_p (insn))
|
||
{
|
||
jump_chain[INSN_UID (insn)]
|
||
= jump_chain[INSN_UID (JUMP_LABEL (insn))];
|
||
jump_chain[INSN_UID (JUMP_LABEL (insn))] = insn;
|
||
}
|
||
if (GET_CODE (PATTERN (insn)) == RETURN)
|
||
{
|
||
jump_chain[INSN_UID (insn)] = jump_chain[0];
|
||
jump_chain[0] = insn;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Delete all labels already not referenced.
|
||
Also find and return the last insn. */
|
||
|
||
static rtx
|
||
delete_unreferenced_labels (f)
|
||
rtx f;
|
||
{
|
||
rtx final = NULL_RTX;
|
||
rtx insn;
|
||
|
||
for (insn = f; insn; )
|
||
{
|
||
if (GET_CODE (insn) == CODE_LABEL && LABEL_NUSES (insn) == 0)
|
||
insn = delete_insn (insn);
|
||
else
|
||
{
|
||
final = insn;
|
||
insn = NEXT_INSN (insn);
|
||
}
|
||
}
|
||
|
||
return final;
|
||
}
|
||
|
||
/* Delete various simple forms of moves which have no necessary
|
||
side effect. */
|
||
|
||
static void
|
||
delete_noop_moves (f)
|
||
rtx f;
|
||
{
|
||
rtx insn, next;
|
||
|
||
for (insn = f; insn; )
|
||
{
|
||
next = NEXT_INSN (insn);
|
||
|
||
if (GET_CODE (insn) == INSN)
|
||
{
|
||
register rtx body = PATTERN (insn);
|
||
|
||
/* Combine stack_adjusts with following push_insns. */
|
||
#ifdef PUSH_ROUNDING
|
||
if (GET_CODE (body) == SET
|
||
&& SET_DEST (body) == stack_pointer_rtx
|
||
&& GET_CODE (SET_SRC (body)) == PLUS
|
||
&& XEXP (SET_SRC (body), 0) == stack_pointer_rtx
|
||
&& GET_CODE (XEXP (SET_SRC (body), 1)) == CONST_INT
|
||
&& INTVAL (XEXP (SET_SRC (body), 1)) > 0)
|
||
{
|
||
rtx p;
|
||
rtx stack_adjust_insn = insn;
|
||
int stack_adjust_amount = INTVAL (XEXP (SET_SRC (body), 1));
|
||
int total_pushed = 0;
|
||
int pushes = 0;
|
||
|
||
/* Find all successive push insns. */
|
||
p = insn;
|
||
/* Don't convert more than three pushes;
|
||
that starts adding too many displaced addresses
|
||
and the whole thing starts becoming a losing
|
||
proposition. */
|
||
while (pushes < 3)
|
||
{
|
||
rtx pbody, dest;
|
||
p = next_nonnote_insn (p);
|
||
if (p == 0 || GET_CODE (p) != INSN)
|
||
break;
|
||
pbody = PATTERN (p);
|
||
if (GET_CODE (pbody) != SET)
|
||
break;
|
||
dest = SET_DEST (pbody);
|
||
/* Allow a no-op move between the adjust and the push. */
|
||
if (GET_CODE (dest) == REG
|
||
&& GET_CODE (SET_SRC (pbody)) == REG
|
||
&& REGNO (dest) == REGNO (SET_SRC (pbody)))
|
||
continue;
|
||
if (! (GET_CODE (dest) == MEM
|
||
&& GET_CODE (XEXP (dest, 0)) == POST_INC
|
||
&& XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
|
||
break;
|
||
pushes++;
|
||
if (total_pushed + GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)))
|
||
> stack_adjust_amount)
|
||
break;
|
||
total_pushed += GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
|
||
}
|
||
|
||
/* Discard the amount pushed from the stack adjust;
|
||
maybe eliminate it entirely. */
|
||
if (total_pushed >= stack_adjust_amount)
|
||
{
|
||
delete_computation (stack_adjust_insn);
|
||
total_pushed = stack_adjust_amount;
|
||
}
|
||
else
|
||
XEXP (SET_SRC (PATTERN (stack_adjust_insn)), 1)
|
||
= GEN_INT (stack_adjust_amount - total_pushed);
|
||
|
||
/* Change the appropriate push insns to ordinary stores. */
|
||
p = insn;
|
||
while (total_pushed > 0)
|
||
{
|
||
rtx pbody, dest;
|
||
p = next_nonnote_insn (p);
|
||
if (GET_CODE (p) != INSN)
|
||
break;
|
||
pbody = PATTERN (p);
|
||
if (GET_CODE (pbody) != SET)
|
||
break;
|
||
dest = SET_DEST (pbody);
|
||
/* Allow a no-op move between the adjust and the push. */
|
||
if (GET_CODE (dest) == REG
|
||
&& GET_CODE (SET_SRC (pbody)) == REG
|
||
&& REGNO (dest) == REGNO (SET_SRC (pbody)))
|
||
continue;
|
||
if (! (GET_CODE (dest) == MEM
|
||
&& GET_CODE (XEXP (dest, 0)) == POST_INC
|
||
&& XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx))
|
||
break;
|
||
total_pushed -= GET_MODE_SIZE (GET_MODE (SET_DEST (pbody)));
|
||
/* If this push doesn't fully fit in the space
|
||
of the stack adjust that we deleted,
|
||
make another stack adjust here for what we
|
||
didn't use up. There should be peepholes
|
||
to recognize the resulting sequence of insns. */
|
||
if (total_pushed < 0)
|
||
{
|
||
emit_insn_before (gen_add2_insn (stack_pointer_rtx,
|
||
GEN_INT (- total_pushed)),
|
||
p);
|
||
break;
|
||
}
|
||
XEXP (dest, 0)
|
||
= plus_constant (stack_pointer_rtx, total_pushed);
|
||
}
|
||
}
|
||
#endif
|
||
|
||
/* Detect and delete no-op move instructions
|
||
resulting from not allocating a parameter in a register. */
|
||
|
||
if (GET_CODE (body) == SET
|
||
&& (SET_DEST (body) == SET_SRC (body)
|
||
|| (GET_CODE (SET_DEST (body)) == MEM
|
||
&& GET_CODE (SET_SRC (body)) == MEM
|
||
&& rtx_equal_p (SET_SRC (body), SET_DEST (body))))
|
||
&& ! (GET_CODE (SET_DEST (body)) == MEM
|
||
&& MEM_VOLATILE_P (SET_DEST (body)))
|
||
&& ! (GET_CODE (SET_SRC (body)) == MEM
|
||
&& MEM_VOLATILE_P (SET_SRC (body))))
|
||
delete_computation (insn);
|
||
|
||
/* Detect and ignore no-op move instructions
|
||
resulting from smart or fortuitous register allocation. */
|
||
|
||
else if (GET_CODE (body) == SET)
|
||
{
|
||
int sreg = true_regnum (SET_SRC (body));
|
||
int dreg = true_regnum (SET_DEST (body));
|
||
|
||
if (sreg == dreg && sreg >= 0)
|
||
delete_insn (insn);
|
||
else if (sreg >= 0 && dreg >= 0)
|
||
{
|
||
rtx trial;
|
||
rtx tem = find_equiv_reg (NULL_RTX, insn, 0,
|
||
sreg, NULL_PTR, dreg,
|
||
GET_MODE (SET_SRC (body)));
|
||
|
||
if (tem != 0
|
||
&& GET_MODE (tem) == GET_MODE (SET_DEST (body)))
|
||
{
|
||
/* DREG may have been the target of a REG_DEAD note in
|
||
the insn which makes INSN redundant. If so, reorg
|
||
would still think it is dead. So search for such a
|
||
note and delete it if we find it. */
|
||
if (! find_regno_note (insn, REG_UNUSED, dreg))
|
||
for (trial = prev_nonnote_insn (insn);
|
||
trial && GET_CODE (trial) != CODE_LABEL;
|
||
trial = prev_nonnote_insn (trial))
|
||
if (find_regno_note (trial, REG_DEAD, dreg))
|
||
{
|
||
remove_death (dreg, trial);
|
||
break;
|
||
}
|
||
|
||
/* Deleting insn could lose a death-note for SREG. */
|
||
if ((trial = find_regno_note (insn, REG_DEAD, sreg)))
|
||
{
|
||
/* Change this into a USE so that we won't emit
|
||
code for it, but still can keep the note. */
|
||
PATTERN (insn)
|
||
= gen_rtx_USE (VOIDmode, XEXP (trial, 0));
|
||
INSN_CODE (insn) = -1;
|
||
/* Remove all reg notes but the REG_DEAD one. */
|
||
REG_NOTES (insn) = trial;
|
||
XEXP (trial, 1) = NULL_RTX;
|
||
}
|
||
else
|
||
delete_insn (insn);
|
||
}
|
||
}
|
||
else if (dreg >= 0 && CONSTANT_P (SET_SRC (body))
|
||
&& find_equiv_reg (SET_SRC (body), insn, 0, dreg,
|
||
NULL_PTR, 0,
|
||
GET_MODE (SET_DEST (body))))
|
||
{
|
||
/* This handles the case where we have two consecutive
|
||
assignments of the same constant to pseudos that didn't
|
||
get a hard reg. Each SET from the constant will be
|
||
converted into a SET of the spill register and an
|
||
output reload will be made following it. This produces
|
||
two loads of the same constant into the same spill
|
||
register. */
|
||
|
||
rtx in_insn = insn;
|
||
|
||
/* Look back for a death note for the first reg.
|
||
If there is one, it is no longer accurate. */
|
||
while (in_insn && GET_CODE (in_insn) != CODE_LABEL)
|
||
{
|
||
if ((GET_CODE (in_insn) == INSN
|
||
|| GET_CODE (in_insn) == JUMP_INSN)
|
||
&& find_regno_note (in_insn, REG_DEAD, dreg))
|
||
{
|
||
remove_death (dreg, in_insn);
|
||
break;
|
||
}
|
||
in_insn = PREV_INSN (in_insn);
|
||
}
|
||
|
||
/* Delete the second load of the value. */
|
||
delete_insn (insn);
|
||
}
|
||
}
|
||
else if (GET_CODE (body) == PARALLEL)
|
||
{
|
||
/* If each part is a set between two identical registers or
|
||
a USE or CLOBBER, delete the insn. */
|
||
int i, sreg, dreg;
|
||
rtx tem;
|
||
|
||
for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
|
||
{
|
||
tem = XVECEXP (body, 0, i);
|
||
if (GET_CODE (tem) == USE || GET_CODE (tem) == CLOBBER)
|
||
continue;
|
||
|
||
if (GET_CODE (tem) != SET
|
||
|| (sreg = true_regnum (SET_SRC (tem))) < 0
|
||
|| (dreg = true_regnum (SET_DEST (tem))) < 0
|
||
|| dreg != sreg)
|
||
break;
|
||
}
|
||
|
||
if (i < 0)
|
||
delete_insn (insn);
|
||
}
|
||
/* Also delete insns to store bit fields if they are no-ops. */
|
||
/* Not worth the hair to detect this in the big-endian case. */
|
||
else if (! BYTES_BIG_ENDIAN
|
||
&& GET_CODE (body) == SET
|
||
&& GET_CODE (SET_DEST (body)) == ZERO_EXTRACT
|
||
&& XEXP (SET_DEST (body), 2) == const0_rtx
|
||
&& XEXP (SET_DEST (body), 0) == SET_SRC (body)
|
||
&& ! (GET_CODE (SET_SRC (body)) == MEM
|
||
&& MEM_VOLATILE_P (SET_SRC (body))))
|
||
delete_insn (insn);
|
||
}
|
||
insn = next;
|
||
}
|
||
}
|
||
|
||
/* See if there is still a NOTE_INSN_FUNCTION_END in this function.
|
||
If so indicate that this function can drop off the end by returning
|
||
1, else return 0.
|
||
|
||
CHECK_DELETED indicates whether we must check if the note being
|
||
searched for has the deleted flag set.
|
||
|
||
DELETE_FINAL_NOTE indicates whether we should delete the note
|
||
if we find it. */
|
||
|
||
static int
|
||
calculate_can_reach_end (last, check_deleted, delete_final_note)
|
||
rtx last;
|
||
int check_deleted;
|
||
int delete_final_note;
|
||
{
|
||
rtx insn = last;
|
||
int n_labels = 1;
|
||
|
||
while (insn != NULL_RTX)
|
||
{
|
||
int ok = 0;
|
||
|
||
/* One label can follow the end-note: the return label. */
|
||
if (GET_CODE (insn) == CODE_LABEL && n_labels-- > 0)
|
||
ok = 1;
|
||
/* Ordinary insns can follow it if returning a structure. */
|
||
else if (GET_CODE (insn) == INSN)
|
||
ok = 1;
|
||
/* If machine uses explicit RETURN insns, no epilogue,
|
||
then one of them follows the note. */
|
||
else if (GET_CODE (insn) == JUMP_INSN
|
||
&& GET_CODE (PATTERN (insn)) == RETURN)
|
||
ok = 1;
|
||
/* A barrier can follow the return insn. */
|
||
else if (GET_CODE (insn) == BARRIER)
|
||
ok = 1;
|
||
/* Other kinds of notes can follow also. */
|
||
else if (GET_CODE (insn) == NOTE
|
||
&& NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
|
||
ok = 1;
|
||
|
||
if (ok != 1)
|
||
break;
|
||
|
||
insn = PREV_INSN (insn);
|
||
}
|
||
|
||
/* See if we backed up to the appropriate type of note. */
|
||
if (insn != NULL_RTX
|
||
&& GET_CODE (insn) == NOTE
|
||
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_END
|
||
&& (check_deleted == 0
|
||
|| ! INSN_DELETED_P (insn)))
|
||
{
|
||
if (delete_final_note)
|
||
delete_insn (insn);
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional
|
||
jump. Assume that this unconditional jump is to the exit test code. If
|
||
the code is sufficiently simple, make a copy of it before INSN,
|
||
followed by a jump to the exit of the loop. Then delete the unconditional
|
||
jump after INSN.
|
||
|
||
Return 1 if we made the change, else 0.
|
||
|
||
This is only safe immediately after a regscan pass because it uses the
|
||
values of regno_first_uid and regno_last_uid. */
|
||
|
||
static int
|
||
duplicate_loop_exit_test (loop_start)
|
||
rtx loop_start;
|
||
{
|
||
rtx insn, set, reg, p, link;
|
||
rtx copy = 0;
|
||
int num_insns = 0;
|
||
rtx exitcode = NEXT_INSN (JUMP_LABEL (next_nonnote_insn (loop_start)));
|
||
rtx lastexit;
|
||
int max_reg = max_reg_num ();
|
||
rtx *reg_map = 0;
|
||
|
||
/* Scan the exit code. We do not perform this optimization if any insn:
|
||
|
||
is a CALL_INSN
|
||
is a CODE_LABEL
|
||
has a REG_RETVAL or REG_LIBCALL note (hard to adjust)
|
||
is a NOTE_INSN_LOOP_BEG because this means we have a nested loop
|
||
is a NOTE_INSN_BLOCK_{BEG,END} because duplicating these notes
|
||
is not valid.
|
||
|
||
We also do not do this if we find an insn with ASM_OPERANDS. While
|
||
this restriction should not be necessary, copying an insn with
|
||
ASM_OPERANDS can confuse asm_noperands in some cases.
|
||
|
||
Also, don't do this if the exit code is more than 20 insns. */
|
||
|
||
for (insn = exitcode;
|
||
insn
|
||
&& ! (GET_CODE (insn) == NOTE
|
||
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END);
|
||
insn = NEXT_INSN (insn))
|
||
{
|
||
switch (GET_CODE (insn))
|
||
{
|
||
case CODE_LABEL:
|
||
case CALL_INSN:
|
||
return 0;
|
||
case NOTE:
|
||
/* We could be in front of the wrong NOTE_INSN_LOOP_END if there is
|
||
a jump immediately after the loop start that branches outside
|
||
the loop but within an outer loop, near the exit test.
|
||
If we copied this exit test and created a phony
|
||
NOTE_INSN_LOOP_VTOP, this could make instructions immediately
|
||
before the exit test look like these could be safely moved
|
||
out of the loop even if they actually may be never executed.
|
||
This can be avoided by checking here for NOTE_INSN_LOOP_CONT. */
|
||
|
||
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
|
||
|| NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT)
|
||
return 0;
|
||
|
||
if (optimize < 2
|
||
&& (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
|
||
|| NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
|
||
/* If we were to duplicate this code, we would not move
|
||
the BLOCK notes, and so debugging the moved code would
|
||
be difficult. Thus, we only move the code with -O2 or
|
||
higher. */
|
||
return 0;
|
||
|
||
break;
|
||
case JUMP_INSN:
|
||
case INSN:
|
||
/* The code below would grossly mishandle REG_WAS_0 notes,
|
||
so get rid of them here. */
|
||
while ((p = find_reg_note (insn, REG_WAS_0, NULL_RTX)) != 0)
|
||
remove_note (insn, p);
|
||
if (++num_insns > 20
|
||
|| find_reg_note (insn, REG_RETVAL, NULL_RTX)
|
||
|| find_reg_note (insn, REG_LIBCALL, NULL_RTX)
|
||
|| asm_noperands (PATTERN (insn)) > 0)
|
||
return 0;
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Unless INSN is zero, we can do the optimization. */
|
||
if (insn == 0)
|
||
return 0;
|
||
|
||
lastexit = insn;
|
||
|
||
/* See if any insn sets a register only used in the loop exit code and
|
||
not a user variable. If so, replace it with a new register. */
|
||
for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
|
||
if (GET_CODE (insn) == INSN
|
||
&& (set = single_set (insn)) != 0
|
||
&& ((reg = SET_DEST (set), GET_CODE (reg) == REG)
|
||
|| (GET_CODE (reg) == SUBREG
|
||
&& (reg = SUBREG_REG (reg), GET_CODE (reg) == REG)))
|
||
&& REGNO (reg) >= FIRST_PSEUDO_REGISTER
|
||
&& REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn))
|
||
{
|
||
for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p))
|
||
if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p))
|
||
break;
|
||
|
||
if (p != lastexit)
|
||
{
|
||
/* We can do the replacement. Allocate reg_map if this is the
|
||
first replacement we found. */
|
||
if (reg_map == 0)
|
||
{
|
||
reg_map = (rtx *) alloca (max_reg * sizeof (rtx));
|
||
bzero ((char *) reg_map, max_reg * sizeof (rtx));
|
||
}
|
||
|
||
REG_LOOP_TEST_P (reg) = 1;
|
||
|
||
reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg));
|
||
}
|
||
}
|
||
|
||
/* Now copy each insn. */
|
||
for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn))
|
||
switch (GET_CODE (insn))
|
||
{
|
||
case BARRIER:
|
||
copy = emit_barrier_before (loop_start);
|
||
break;
|
||
case NOTE:
|
||
/* Only copy line-number notes. */
|
||
if (NOTE_LINE_NUMBER (insn) >= 0)
|
||
{
|
||
copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start);
|
||
NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn);
|
||
}
|
||
break;
|
||
|
||
case INSN:
|
||
copy = emit_insn_before (copy_rtx (PATTERN (insn)), loop_start);
|
||
if (reg_map)
|
||
replace_regs (PATTERN (copy), reg_map, max_reg, 1);
|
||
|
||
mark_jump_label (PATTERN (copy), copy, 0);
|
||
|
||
/* Copy all REG_NOTES except REG_LABEL since mark_jump_label will
|
||
make them. */
|
||
for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
|
||
if (REG_NOTE_KIND (link) != REG_LABEL)
|
||
REG_NOTES (copy)
|
||
= copy_rtx (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link),
|
||
XEXP (link, 0),
|
||
REG_NOTES (copy)));
|
||
if (reg_map && REG_NOTES (copy))
|
||
replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
|
||
break;
|
||
|
||
case JUMP_INSN:
|
||
copy = emit_jump_insn_before (copy_rtx (PATTERN (insn)), loop_start);
|
||
if (reg_map)
|
||
replace_regs (PATTERN (copy), reg_map, max_reg, 1);
|
||
mark_jump_label (PATTERN (copy), copy, 0);
|
||
if (REG_NOTES (insn))
|
||
{
|
||
REG_NOTES (copy) = copy_rtx (REG_NOTES (insn));
|
||
if (reg_map)
|
||
replace_regs (REG_NOTES (copy), reg_map, max_reg, 1);
|
||
}
|
||
|
||
/* If this is a simple jump, add it to the jump chain. */
|
||
|
||
if (INSN_UID (copy) < max_jump_chain && JUMP_LABEL (copy)
|
||
&& simplejump_p (copy))
|
||
{
|
||
jump_chain[INSN_UID (copy)]
|
||
= jump_chain[INSN_UID (JUMP_LABEL (copy))];
|
||
jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
|
||
/* Now clean up by emitting a jump to the end label and deleting the jump
|
||
at the start of the loop. */
|
||
if (! copy || GET_CODE (copy) != BARRIER)
|
||
{
|
||
copy = emit_jump_insn_before (gen_jump (get_label_after (insn)),
|
||
loop_start);
|
||
mark_jump_label (PATTERN (copy), copy, 0);
|
||
if (INSN_UID (copy) < max_jump_chain
|
||
&& INSN_UID (JUMP_LABEL (copy)) < max_jump_chain)
|
||
{
|
||
jump_chain[INSN_UID (copy)]
|
||
= jump_chain[INSN_UID (JUMP_LABEL (copy))];
|
||
jump_chain[INSN_UID (JUMP_LABEL (copy))] = copy;
|
||
}
|
||
emit_barrier_before (loop_start);
|
||
}
|
||
|
||
/* Mark the exit code as the virtual top of the converted loop. */
|
||
emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode);
|
||
|
||
delete_insn (next_nonnote_insn (loop_start));
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, and
|
||
loop-end notes between START and END out before START. Assume that
|
||
END is not such a note. START may be such a note. Returns the value
|
||
of the new starting insn, which may be different if the original start
|
||
was such a note. */
|
||
|
||
rtx
|
||
squeeze_notes (start, end)
|
||
rtx start, end;
|
||
{
|
||
rtx insn;
|
||
rtx next;
|
||
|
||
for (insn = start; insn != end; insn = next)
|
||
{
|
||
next = NEXT_INSN (insn);
|
||
if (GET_CODE (insn) == NOTE
|
||
&& (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
|
||
|| NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
|
||
|| NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG
|
||
|| NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END
|
||
|| NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT
|
||
|| NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP))
|
||
{
|
||
if (insn == start)
|
||
start = next;
|
||
else
|
||
{
|
||
rtx prev = PREV_INSN (insn);
|
||
PREV_INSN (insn) = PREV_INSN (start);
|
||
NEXT_INSN (insn) = start;
|
||
NEXT_INSN (PREV_INSN (insn)) = insn;
|
||
PREV_INSN (NEXT_INSN (insn)) = insn;
|
||
NEXT_INSN (prev) = next;
|
||
PREV_INSN (next) = prev;
|
||
}
|
||
}
|
||
}
|
||
|
||
return start;
|
||
}
|
||
|
||
/* Compare the instructions before insn E1 with those before E2
|
||
to find an opportunity for cross jumping.
|
||
(This means detecting identical sequences of insns followed by
|
||
jumps to the same place, or followed by a label and a jump
|
||
to that label, and replacing one with a jump to the other.)
|
||
|
||
Assume E1 is a jump that jumps to label E2
|
||
(that is not always true but it might as well be).
|
||
Find the longest possible equivalent sequences
|
||
and store the first insns of those sequences into *F1 and *F2.
|
||
Store zero there if no equivalent preceding instructions are found.
|
||
|
||
We give up if we find a label in stream 1.
|
||
Actually we could transfer that label into stream 2. */
|
||
|
||
static void
|
||
find_cross_jump (e1, e2, minimum, f1, f2)
|
||
rtx e1, e2;
|
||
int minimum;
|
||
rtx *f1, *f2;
|
||
{
|
||
register rtx i1 = e1, i2 = e2;
|
||
register rtx p1, p2;
|
||
int lose = 0;
|
||
|
||
rtx last1 = 0, last2 = 0;
|
||
rtx afterlast1 = 0, afterlast2 = 0;
|
||
|
||
*f1 = 0;
|
||
*f2 = 0;
|
||
|
||
while (1)
|
||
{
|
||
i1 = prev_nonnote_insn (i1);
|
||
|
||
i2 = PREV_INSN (i2);
|
||
while (i2 && (GET_CODE (i2) == NOTE || GET_CODE (i2) == CODE_LABEL))
|
||
i2 = PREV_INSN (i2);
|
||
|
||
if (i1 == 0)
|
||
break;
|
||
|
||
/* Don't allow the range of insns preceding E1 or E2
|
||
to include the other (E2 or E1). */
|
||
if (i2 == e1 || i1 == e2)
|
||
break;
|
||
|
||
/* If we will get to this code by jumping, those jumps will be
|
||
tensioned to go directly to the new label (before I2),
|
||
so this cross-jumping won't cost extra. So reduce the minimum. */
|
||
if (GET_CODE (i1) == CODE_LABEL)
|
||
{
|
||
--minimum;
|
||
break;
|
||
}
|
||
|
||
if (i2 == 0 || GET_CODE (i1) != GET_CODE (i2))
|
||
break;
|
||
|
||
/* Avoid moving insns across EH regions if either of the insns
|
||
can throw. */
|
||
if (flag_exceptions
|
||
&& (asynchronous_exceptions || GET_CODE (i1) == CALL_INSN)
|
||
&& !in_same_eh_region (i1, i2))
|
||
break;
|
||
|
||
p1 = PATTERN (i1);
|
||
p2 = PATTERN (i2);
|
||
|
||
/* If this is a CALL_INSN, compare register usage information.
|
||
If we don't check this on stack register machines, the two
|
||
CALL_INSNs might be merged leaving reg-stack.c with mismatching
|
||
numbers of stack registers in the same basic block.
|
||
If we don't check this on machines with delay slots, a delay slot may
|
||
be filled that clobbers a parameter expected by the subroutine.
|
||
|
||
??? We take the simple route for now and assume that if they're
|
||
equal, they were constructed identically. */
|
||
|
||
if (GET_CODE (i1) == CALL_INSN
|
||
&& ! rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
|
||
CALL_INSN_FUNCTION_USAGE (i2)))
|
||
lose = 1;
|
||
|
||
#ifdef STACK_REGS
|
||
/* If cross_jump_death_matters is not 0, the insn's mode
|
||
indicates whether or not the insn contains any stack-like
|
||
regs. */
|
||
|
||
if (!lose && cross_jump_death_matters && stack_regs_mentioned (i1))
|
||
{
|
||
/* If register stack conversion has already been done, then
|
||
death notes must also be compared before it is certain that
|
||
the two instruction streams match. */
|
||
|
||
rtx note;
|
||
HARD_REG_SET i1_regset, i2_regset;
|
||
|
||
CLEAR_HARD_REG_SET (i1_regset);
|
||
CLEAR_HARD_REG_SET (i2_regset);
|
||
|
||
for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
|
||
if (REG_NOTE_KIND (note) == REG_DEAD
|
||
&& STACK_REG_P (XEXP (note, 0)))
|
||
SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
|
||
|
||
for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
|
||
if (REG_NOTE_KIND (note) == REG_DEAD
|
||
&& STACK_REG_P (XEXP (note, 0)))
|
||
SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
|
||
|
||
GO_IF_HARD_REG_EQUAL (i1_regset, i2_regset, done);
|
||
|
||
lose = 1;
|
||
|
||
done:
|
||
;
|
||
}
|
||
#endif
|
||
|
||
/* Don't allow old-style asm or volatile extended asms to be accepted
|
||
for cross jumping purposes. It is conceptually correct to allow
|
||
them, since cross-jumping preserves the dynamic instruction order
|
||
even though it is changing the static instruction order. However,
|
||
if an asm is being used to emit an assembler pseudo-op, such as
|
||
the MIPS `.set reorder' pseudo-op, then the static instruction order
|
||
matters and it must be preserved. */
|
||
if (GET_CODE (p1) == ASM_INPUT || GET_CODE (p2) == ASM_INPUT
|
||
|| (GET_CODE (p1) == ASM_OPERANDS && MEM_VOLATILE_P (p1))
|
||
|| (GET_CODE (p2) == ASM_OPERANDS && MEM_VOLATILE_P (p2)))
|
||
lose = 1;
|
||
|
||
if (lose || GET_CODE (p1) != GET_CODE (p2)
|
||
|| ! rtx_renumbered_equal_p (p1, p2))
|
||
{
|
||
/* The following code helps take care of G++ cleanups. */
|
||
rtx equiv1;
|
||
rtx equiv2;
|
||
|
||
if (!lose && GET_CODE (p1) == GET_CODE (p2)
|
||
&& ((equiv1 = find_reg_note (i1, REG_EQUAL, NULL_RTX)) != 0
|
||
|| (equiv1 = find_reg_note (i1, REG_EQUIV, NULL_RTX)) != 0)
|
||
&& ((equiv2 = find_reg_note (i2, REG_EQUAL, NULL_RTX)) != 0
|
||
|| (equiv2 = find_reg_note (i2, REG_EQUIV, NULL_RTX)) != 0)
|
||
/* If the equivalences are not to a constant, they may
|
||
reference pseudos that no longer exist, so we can't
|
||
use them. */
|
||
&& CONSTANT_P (XEXP (equiv1, 0))
|
||
&& rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
|
||
{
|
||
rtx s1 = single_set (i1);
|
||
rtx s2 = single_set (i2);
|
||
if (s1 != 0 && s2 != 0
|
||
&& rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
|
||
{
|
||
validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
|
||
validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
|
||
if (! rtx_renumbered_equal_p (p1, p2))
|
||
cancel_changes (0);
|
||
else if (apply_change_group ())
|
||
goto win;
|
||
}
|
||
}
|
||
|
||
/* Insns fail to match; cross jumping is limited to the following
|
||
insns. */
|
||
|
||
#ifdef HAVE_cc0
|
||
/* Don't allow the insn after a compare to be shared by
|
||
cross-jumping unless the compare is also shared.
|
||
Here, if either of these non-matching insns is a compare,
|
||
exclude the following insn from possible cross-jumping. */
|
||
if (sets_cc0_p (p1) || sets_cc0_p (p2))
|
||
last1 = afterlast1, last2 = afterlast2, ++minimum;
|
||
#endif
|
||
|
||
/* If cross-jumping here will feed a jump-around-jump
|
||
optimization, this jump won't cost extra, so reduce
|
||
the minimum. */
|
||
if (GET_CODE (i1) == JUMP_INSN
|
||
&& JUMP_LABEL (i1)
|
||
&& prev_real_insn (JUMP_LABEL (i1)) == e1)
|
||
--minimum;
|
||
break;
|
||
}
|
||
|
||
win:
|
||
if (GET_CODE (p1) != USE && GET_CODE (p1) != CLOBBER)
|
||
{
|
||
/* Ok, this insn is potentially includable in a cross-jump here. */
|
||
afterlast1 = last1, afterlast2 = last2;
|
||
last1 = i1, last2 = i2, --minimum;
|
||
}
|
||
}
|
||
|
||
if (minimum <= 0 && last1 != 0 && last1 != e1)
|
||
*f1 = last1, *f2 = last2;
|
||
}
|
||
|
||
static void
|
||
do_cross_jump (insn, newjpos, newlpos)
|
||
rtx insn, newjpos, newlpos;
|
||
{
|
||
/* Find an existing label at this point
|
||
or make a new one if there is none. */
|
||
register rtx label = get_label_before (newlpos);
|
||
|
||
/* Make the same jump insn jump to the new point. */
|
||
if (GET_CODE (PATTERN (insn)) == RETURN)
|
||
{
|
||
/* Remove from jump chain of returns. */
|
||
delete_from_jump_chain (insn);
|
||
/* Change the insn. */
|
||
PATTERN (insn) = gen_jump (label);
|
||
INSN_CODE (insn) = -1;
|
||
JUMP_LABEL (insn) = label;
|
||
LABEL_NUSES (label)++;
|
||
/* Add to new the jump chain. */
|
||
if (INSN_UID (label) < max_jump_chain
|
||
&& INSN_UID (insn) < max_jump_chain)
|
||
{
|
||
jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (label)];
|
||
jump_chain[INSN_UID (label)] = insn;
|
||
}
|
||
}
|
||
else
|
||
redirect_jump (insn, label);
|
||
|
||
/* Delete the matching insns before the jump. Also, remove any REG_EQUAL
|
||
or REG_EQUIV note in the NEWLPOS stream that isn't also present in
|
||
the NEWJPOS stream. */
|
||
|
||
while (newjpos != insn)
|
||
{
|
||
rtx lnote;
|
||
|
||
for (lnote = REG_NOTES (newlpos); lnote; lnote = XEXP (lnote, 1))
|
||
if ((REG_NOTE_KIND (lnote) == REG_EQUAL
|
||
|| REG_NOTE_KIND (lnote) == REG_EQUIV)
|
||
&& ! find_reg_note (newjpos, REG_EQUAL, XEXP (lnote, 0))
|
||
&& ! find_reg_note (newjpos, REG_EQUIV, XEXP (lnote, 0)))
|
||
remove_note (newlpos, lnote);
|
||
|
||
delete_insn (newjpos);
|
||
newjpos = next_real_insn (newjpos);
|
||
newlpos = next_real_insn (newlpos);
|
||
}
|
||
}
|
||
|
||
/* Return the label before INSN, or put a new label there. */
|
||
|
||
rtx
|
||
get_label_before (insn)
|
||
rtx insn;
|
||
{
|
||
rtx label;
|
||
|
||
/* Find an existing label at this point
|
||
or make a new one if there is none. */
|
||
label = prev_nonnote_insn (insn);
|
||
|
||
if (label == 0 || GET_CODE (label) != CODE_LABEL)
|
||
{
|
||
rtx prev = PREV_INSN (insn);
|
||
|
||
label = gen_label_rtx ();
|
||
emit_label_after (label, prev);
|
||
LABEL_NUSES (label) = 0;
|
||
}
|
||
return label;
|
||
}
|
||
|
||
/* Return the label after INSN, or put a new label there. */
|
||
|
||
rtx
|
||
get_label_after (insn)
|
||
rtx insn;
|
||
{
|
||
rtx label;
|
||
|
||
/* Find an existing label at this point
|
||
or make a new one if there is none. */
|
||
label = next_nonnote_insn (insn);
|
||
|
||
if (label == 0 || GET_CODE (label) != CODE_LABEL)
|
||
{
|
||
label = gen_label_rtx ();
|
||
emit_label_after (label, insn);
|
||
LABEL_NUSES (label) = 0;
|
||
}
|
||
return label;
|
||
}
|
||
|
||
/* Return 1 if INSN is a jump that jumps to right after TARGET
|
||
only on the condition that TARGET itself would drop through.
|
||
Assumes that TARGET is a conditional jump. */
|
||
|
||
static int
|
||
jump_back_p (insn, target)
|
||
rtx insn, target;
|
||
{
|
||
rtx cinsn, ctarget;
|
||
enum rtx_code codei, codet;
|
||
|
||
if (simplejump_p (insn) || ! condjump_p (insn)
|
||
|| simplejump_p (target)
|
||
|| target != prev_real_insn (JUMP_LABEL (insn)))
|
||
return 0;
|
||
|
||
cinsn = XEXP (SET_SRC (PATTERN (insn)), 0);
|
||
ctarget = XEXP (SET_SRC (PATTERN (target)), 0);
|
||
|
||
codei = GET_CODE (cinsn);
|
||
codet = GET_CODE (ctarget);
|
||
|
||
if (XEXP (SET_SRC (PATTERN (insn)), 1) == pc_rtx)
|
||
{
|
||
if (! can_reverse_comparison_p (cinsn, insn))
|
||
return 0;
|
||
codei = reverse_condition (codei);
|
||
}
|
||
|
||
if (XEXP (SET_SRC (PATTERN (target)), 2) == pc_rtx)
|
||
{
|
||
if (! can_reverse_comparison_p (ctarget, target))
|
||
return 0;
|
||
codet = reverse_condition (codet);
|
||
}
|
||
|
||
return (codei == codet
|
||
&& rtx_renumbered_equal_p (XEXP (cinsn, 0), XEXP (ctarget, 0))
|
||
&& rtx_renumbered_equal_p (XEXP (cinsn, 1), XEXP (ctarget, 1)));
|
||
}
|
||
|
||
/* Given a comparison, COMPARISON, inside a conditional jump insn, INSN,
|
||
return non-zero if it is safe to reverse this comparison. It is if our
|
||
floating-point is not IEEE, if this is an NE or EQ comparison, or if
|
||
this is known to be an integer comparison. */
|
||
|
||
int
|
||
can_reverse_comparison_p (comparison, insn)
|
||
rtx comparison;
|
||
rtx insn;
|
||
{
|
||
rtx arg0;
|
||
|
||
/* If this is not actually a comparison, we can't reverse it. */
|
||
if (GET_RTX_CLASS (GET_CODE (comparison)) != '<')
|
||
return 0;
|
||
|
||
if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|
||
/* If this is an NE comparison, it is safe to reverse it to an EQ
|
||
comparison and vice versa, even for floating point. If no operands
|
||
are NaNs, the reversal is valid. If some operand is a NaN, EQ is
|
||
always false and NE is always true, so the reversal is also valid. */
|
||
|| flag_fast_math
|
||
|| GET_CODE (comparison) == NE
|
||
|| GET_CODE (comparison) == EQ)
|
||
return 1;
|
||
|
||
arg0 = XEXP (comparison, 0);
|
||
|
||
/* Make sure ARG0 is one of the actual objects being compared. If we
|
||
can't do this, we can't be sure the comparison can be reversed.
|
||
|
||
Handle cc0 and a MODE_CC register. */
|
||
if ((GET_CODE (arg0) == REG && GET_MODE_CLASS (GET_MODE (arg0)) == MODE_CC)
|
||
#ifdef HAVE_cc0
|
||
|| arg0 == cc0_rtx
|
||
#endif
|
||
)
|
||
{
|
||
rtx prev = prev_nonnote_insn (insn);
|
||
rtx set;
|
||
|
||
/* If the comparison itself was a loop invariant, it could have been
|
||
hoisted out of the loop. If we proceed to unroll such a loop, then
|
||
we may not be able to find the comparison when copying the loop.
|
||
|
||
Returning zero in that case is the safe thing to do. */
|
||
if (prev == 0)
|
||
return 0;
|
||
|
||
set = single_set (prev);
|
||
if (set == 0 || SET_DEST (set) != arg0)
|
||
return 0;
|
||
|
||
arg0 = SET_SRC (set);
|
||
|
||
if (GET_CODE (arg0) == COMPARE)
|
||
arg0 = XEXP (arg0, 0);
|
||
}
|
||
|
||
/* We can reverse this if ARG0 is a CONST_INT or if its mode is
|
||
not VOIDmode and neither a MODE_CC nor MODE_FLOAT type. */
|
||
return (GET_CODE (arg0) == CONST_INT
|
||
|| (GET_MODE (arg0) != VOIDmode
|
||
&& GET_MODE_CLASS (GET_MODE (arg0)) != MODE_CC
|
||
&& GET_MODE_CLASS (GET_MODE (arg0)) != MODE_FLOAT));
|
||
}
|
||
|
||
/* Given an rtx-code for a comparison, return the code
|
||
for the negated comparison.
|
||
WATCH OUT! reverse_condition is not safe to use on a jump
|
||
that might be acting on the results of an IEEE floating point comparison,
|
||
because of the special treatment of non-signaling nans in comparisons.
|
||
Use can_reverse_comparison_p to be sure. */
|
||
|
||
enum rtx_code
|
||
reverse_condition (code)
|
||
enum rtx_code code;
|
||
{
|
||
switch (code)
|
||
{
|
||
case EQ:
|
||
return NE;
|
||
|
||
case NE:
|
||
return EQ;
|
||
|
||
case GT:
|
||
return LE;
|
||
|
||
case GE:
|
||
return LT;
|
||
|
||
case LT:
|
||
return GE;
|
||
|
||
case LE:
|
||
return GT;
|
||
|
||
case GTU:
|
||
return LEU;
|
||
|
||
case GEU:
|
||
return LTU;
|
||
|
||
case LTU:
|
||
return GEU;
|
||
|
||
case LEU:
|
||
return GTU;
|
||
|
||
default:
|
||
abort ();
|
||
return UNKNOWN;
|
||
}
|
||
}
|
||
|
||
/* Similar, but return the code when two operands of a comparison are swapped.
|
||
This IS safe for IEEE floating-point. */
|
||
|
||
enum rtx_code
|
||
swap_condition (code)
|
||
enum rtx_code code;
|
||
{
|
||
switch (code)
|
||
{
|
||
case EQ:
|
||
case NE:
|
||
return code;
|
||
|
||
case GT:
|
||
return LT;
|
||
|
||
case GE:
|
||
return LE;
|
||
|
||
case LT:
|
||
return GT;
|
||
|
||
case LE:
|
||
return GE;
|
||
|
||
case GTU:
|
||
return LTU;
|
||
|
||
case GEU:
|
||
return LEU;
|
||
|
||
case LTU:
|
||
return GTU;
|
||
|
||
case LEU:
|
||
return GEU;
|
||
|
||
default:
|
||
abort ();
|
||
return UNKNOWN;
|
||
}
|
||
}
|
||
|
||
/* Given a comparison CODE, return the corresponding unsigned comparison.
|
||
If CODE is an equality comparison or already an unsigned comparison,
|
||
CODE is returned. */
|
||
|
||
enum rtx_code
|
||
unsigned_condition (code)
|
||
enum rtx_code code;
|
||
{
|
||
switch (code)
|
||
{
|
||
case EQ:
|
||
case NE:
|
||
case GTU:
|
||
case GEU:
|
||
case LTU:
|
||
case LEU:
|
||
return code;
|
||
|
||
case GT:
|
||
return GTU;
|
||
|
||
case GE:
|
||
return GEU;
|
||
|
||
case LT:
|
||
return LTU;
|
||
|
||
case LE:
|
||
return LEU;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* Similarly, return the signed version of a comparison. */
|
||
|
||
enum rtx_code
|
||
signed_condition (code)
|
||
enum rtx_code code;
|
||
{
|
||
switch (code)
|
||
{
|
||
case EQ:
|
||
case NE:
|
||
case GT:
|
||
case GE:
|
||
case LT:
|
||
case LE:
|
||
return code;
|
||
|
||
case GTU:
|
||
return GT;
|
||
|
||
case GEU:
|
||
return GE;
|
||
|
||
case LTU:
|
||
return LT;
|
||
|
||
case LEU:
|
||
return LE;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
|
||
/* Return non-zero if CODE1 is more strict than CODE2, i.e., if the
|
||
truth of CODE1 implies the truth of CODE2. */
|
||
|
||
int
|
||
comparison_dominates_p (code1, code2)
|
||
enum rtx_code code1, code2;
|
||
{
|
||
if (code1 == code2)
|
||
return 1;
|
||
|
||
switch (code1)
|
||
{
|
||
case EQ:
|
||
if (code2 == LE || code2 == LEU || code2 == GE || code2 == GEU)
|
||
return 1;
|
||
break;
|
||
|
||
case LT:
|
||
if (code2 == LE || code2 == NE)
|
||
return 1;
|
||
break;
|
||
|
||
case GT:
|
||
if (code2 == GE || code2 == NE)
|
||
return 1;
|
||
break;
|
||
|
||
case LTU:
|
||
if (code2 == LEU || code2 == NE)
|
||
return 1;
|
||
break;
|
||
|
||
case GTU:
|
||
if (code2 == GEU || code2 == NE)
|
||
return 1;
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return 1 if INSN is an unconditional jump and nothing else. */
|
||
|
||
int
|
||
simplejump_p (insn)
|
||
rtx insn;
|
||
{
|
||
return (GET_CODE (insn) == JUMP_INSN
|
||
&& GET_CODE (PATTERN (insn)) == SET
|
||
&& GET_CODE (SET_DEST (PATTERN (insn))) == PC
|
||
&& GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF);
|
||
}
|
||
|
||
/* Return nonzero if INSN is a (possibly) conditional jump
|
||
and nothing more. */
|
||
|
||
int
|
||
condjump_p (insn)
|
||
rtx insn;
|
||
{
|
||
register rtx x = PATTERN (insn);
|
||
if (GET_CODE (x) != SET)
|
||
return 0;
|
||
if (GET_CODE (SET_DEST (x)) != PC)
|
||
return 0;
|
||
if (GET_CODE (SET_SRC (x)) == LABEL_REF)
|
||
return 1;
|
||
if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
|
||
return 0;
|
||
if (XEXP (SET_SRC (x), 2) == pc_rtx
|
||
&& (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
|
||
|| GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
|
||
return 1;
|
||
if (XEXP (SET_SRC (x), 1) == pc_rtx
|
||
&& (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
|
||
|| GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
|
||
return 1;
|
||
return 0;
|
||
}
|
||
|
||
/* Return nonzero if INSN is a (possibly) conditional jump
|
||
and nothing more. */
|
||
|
||
int
|
||
condjump_in_parallel_p (insn)
|
||
rtx insn;
|
||
{
|
||
register rtx x = PATTERN (insn);
|
||
|
||
if (GET_CODE (x) != PARALLEL)
|
||
return 0;
|
||
else
|
||
x = XVECEXP (x, 0, 0);
|
||
|
||
if (GET_CODE (x) != SET)
|
||
return 0;
|
||
if (GET_CODE (SET_DEST (x)) != PC)
|
||
return 0;
|
||
if (GET_CODE (SET_SRC (x)) == LABEL_REF)
|
||
return 1;
|
||
if (GET_CODE (SET_SRC (x)) != IF_THEN_ELSE)
|
||
return 0;
|
||
if (XEXP (SET_SRC (x), 2) == pc_rtx
|
||
&& (GET_CODE (XEXP (SET_SRC (x), 1)) == LABEL_REF
|
||
|| GET_CODE (XEXP (SET_SRC (x), 1)) == RETURN))
|
||
return 1;
|
||
if (XEXP (SET_SRC (x), 1) == pc_rtx
|
||
&& (GET_CODE (XEXP (SET_SRC (x), 2)) == LABEL_REF
|
||
|| GET_CODE (XEXP (SET_SRC (x), 2)) == RETURN))
|
||
return 1;
|
||
return 0;
|
||
}
|
||
|
||
/* Return the label of a conditional jump. */
|
||
|
||
rtx
|
||
condjump_label (insn)
|
||
rtx insn;
|
||
{
|
||
register rtx x = PATTERN (insn);
|
||
|
||
if (GET_CODE (x) == PARALLEL)
|
||
x = XVECEXP (x, 0, 0);
|
||
if (GET_CODE (x) != SET)
|
||
return NULL_RTX;
|
||
if (GET_CODE (SET_DEST (x)) != PC)
|
||
return NULL_RTX;
|
||
x = SET_SRC (x);
|
||
if (GET_CODE (x) == LABEL_REF)
|
||
return x;
|
||
if (GET_CODE (x) != IF_THEN_ELSE)
|
||
return NULL_RTX;
|
||
if (XEXP (x, 2) == pc_rtx && GET_CODE (XEXP (x, 1)) == LABEL_REF)
|
||
return XEXP (x, 1);
|
||
if (XEXP (x, 1) == pc_rtx && GET_CODE (XEXP (x, 2)) == LABEL_REF)
|
||
return XEXP (x, 2);
|
||
return NULL_RTX;
|
||
}
|
||
|
||
/* Return true if INSN is a (possibly conditional) return insn. */
|
||
|
||
static int
|
||
returnjump_p_1 (loc, data)
|
||
rtx *loc;
|
||
void *data ATTRIBUTE_UNUSED;
|
||
{
|
||
rtx x = *loc;
|
||
return GET_CODE (x) == RETURN;
|
||
}
|
||
|
||
int
|
||
returnjump_p (insn)
|
||
rtx insn;
|
||
{
|
||
return for_each_rtx (&PATTERN (insn), returnjump_p_1, NULL);
|
||
}
|
||
|
||
#ifdef HAVE_cc0
|
||
|
||
/* Return 1 if X is an RTX that does nothing but set the condition codes
|
||
and CLOBBER or USE registers.
|
||
Return -1 if X does explicitly set the condition codes,
|
||
but also does other things. */
|
||
|
||
int
|
||
sets_cc0_p (x)
|
||
rtx x ATTRIBUTE_UNUSED;
|
||
{
|
||
if (GET_CODE (x) == SET && SET_DEST (x) == cc0_rtx)
|
||
return 1;
|
||
if (GET_CODE (x) == PARALLEL)
|
||
{
|
||
int i;
|
||
int sets_cc0 = 0;
|
||
int other_things = 0;
|
||
for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
|
||
{
|
||
if (GET_CODE (XVECEXP (x, 0, i)) == SET
|
||
&& SET_DEST (XVECEXP (x, 0, i)) == cc0_rtx)
|
||
sets_cc0 = 1;
|
||
else if (GET_CODE (XVECEXP (x, 0, i)) == SET)
|
||
other_things = 1;
|
||
}
|
||
return ! sets_cc0 ? 0 : other_things ? -1 : 1;
|
||
}
|
||
return 0;
|
||
}
|
||
#endif
|
||
|
||
/* Follow any unconditional jump at LABEL;
|
||
return the ultimate label reached by any such chain of jumps.
|
||
If LABEL is not followed by a jump, return LABEL.
|
||
If the chain loops or we can't find end, return LABEL,
|
||
since that tells caller to avoid changing the insn.
|
||
|
||
If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
|
||
a USE or CLOBBER. */
|
||
|
||
rtx
|
||
follow_jumps (label)
|
||
rtx label;
|
||
{
|
||
register rtx insn;
|
||
register rtx next;
|
||
register rtx value = label;
|
||
register int depth;
|
||
|
||
for (depth = 0;
|
||
(depth < 10
|
||
&& (insn = next_active_insn (value)) != 0
|
||
&& GET_CODE (insn) == JUMP_INSN
|
||
&& ((JUMP_LABEL (insn) != 0 && simplejump_p (insn))
|
||
|| GET_CODE (PATTERN (insn)) == RETURN)
|
||
&& (next = NEXT_INSN (insn))
|
||
&& GET_CODE (next) == BARRIER);
|
||
depth++)
|
||
{
|
||
/* Don't chain through the insn that jumps into a loop
|
||
from outside the loop,
|
||
since that would create multiple loop entry jumps
|
||
and prevent loop optimization. */
|
||
rtx tem;
|
||
if (!reload_completed)
|
||
for (tem = value; tem != insn; tem = NEXT_INSN (tem))
|
||
if (GET_CODE (tem) == NOTE
|
||
&& (NOTE_LINE_NUMBER (tem) == NOTE_INSN_LOOP_BEG
|
||
/* ??? Optional. Disables some optimizations, but makes
|
||
gcov output more accurate with -O. */
|
||
|| (flag_test_coverage && NOTE_LINE_NUMBER (tem) > 0)))
|
||
return value;
|
||
|
||
/* If we have found a cycle, make the insn jump to itself. */
|
||
if (JUMP_LABEL (insn) == label)
|
||
return label;
|
||
|
||
tem = next_active_insn (JUMP_LABEL (insn));
|
||
if (tem && (GET_CODE (PATTERN (tem)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC))
|
||
break;
|
||
|
||
value = JUMP_LABEL (insn);
|
||
}
|
||
if (depth == 10)
|
||
return label;
|
||
return value;
|
||
}
|
||
|
||
/* Assuming that field IDX of X is a vector of label_refs,
|
||
replace each of them by the ultimate label reached by it.
|
||
Return nonzero if a change is made.
|
||
If IGNORE_LOOPS is 0, we do not chain across a NOTE_INSN_LOOP_BEG. */
|
||
|
||
static int
|
||
tension_vector_labels (x, idx)
|
||
register rtx x;
|
||
register int idx;
|
||
{
|
||
int changed = 0;
|
||
register int i;
|
||
for (i = XVECLEN (x, idx) - 1; i >= 0; i--)
|
||
{
|
||
register rtx olabel = XEXP (XVECEXP (x, idx, i), 0);
|
||
register rtx nlabel = follow_jumps (olabel);
|
||
if (nlabel && nlabel != olabel)
|
||
{
|
||
XEXP (XVECEXP (x, idx, i), 0) = nlabel;
|
||
++LABEL_NUSES (nlabel);
|
||
if (--LABEL_NUSES (olabel) == 0)
|
||
delete_insn (olabel);
|
||
changed = 1;
|
||
}
|
||
}
|
||
return changed;
|
||
}
|
||
|
||
/* Find all CODE_LABELs referred to in X, and increment their use counts.
|
||
If INSN is a JUMP_INSN and there is at least one CODE_LABEL referenced
|
||
in INSN, then store one of them in JUMP_LABEL (INSN).
|
||
If INSN is an INSN or a CALL_INSN and there is at least one CODE_LABEL
|
||
referenced in INSN, add a REG_LABEL note containing that label to INSN.
|
||
Also, when there are consecutive labels, canonicalize on the last of them.
|
||
|
||
Note that two labels separated by a loop-beginning note
|
||
must be kept distinct if we have not yet done loop-optimization,
|
||
because the gap between them is where loop-optimize
|
||
will want to move invariant code to. CROSS_JUMP tells us
|
||
that loop-optimization is done with.
|
||
|
||
Once reload has completed (CROSS_JUMP non-zero), we need not consider
|
||
two labels distinct if they are separated by only USE or CLOBBER insns. */
|
||
|
||
static void
|
||
mark_jump_label (x, insn, cross_jump)
|
||
register rtx x;
|
||
rtx insn;
|
||
int cross_jump;
|
||
{
|
||
register RTX_CODE code = GET_CODE (x);
|
||
register int i;
|
||
register char *fmt;
|
||
|
||
switch (code)
|
||
{
|
||
case PC:
|
||
case CC0:
|
||
case REG:
|
||
case SUBREG:
|
||
case CONST_INT:
|
||
case SYMBOL_REF:
|
||
case CONST_DOUBLE:
|
||
case CLOBBER:
|
||
case CALL:
|
||
return;
|
||
|
||
case MEM:
|
||
/* If this is a constant-pool reference, see if it is a label. */
|
||
if (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
|
||
&& CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)))
|
||
mark_jump_label (get_pool_constant (XEXP (x, 0)), insn, cross_jump);
|
||
break;
|
||
|
||
case LABEL_REF:
|
||
{
|
||
rtx label = XEXP (x, 0);
|
||
rtx olabel = label;
|
||
rtx note;
|
||
rtx next;
|
||
|
||
if (GET_CODE (label) != CODE_LABEL)
|
||
abort ();
|
||
|
||
/* Ignore references to labels of containing functions. */
|
||
if (LABEL_REF_NONLOCAL_P (x))
|
||
break;
|
||
|
||
/* If there are other labels following this one,
|
||
replace it with the last of the consecutive labels. */
|
||
for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
|
||
{
|
||
if (GET_CODE (next) == CODE_LABEL)
|
||
label = next;
|
||
else if (cross_jump && GET_CODE (next) == INSN
|
||
&& (GET_CODE (PATTERN (next)) == USE
|
||
|| GET_CODE (PATTERN (next)) == CLOBBER))
|
||
continue;
|
||
else if (GET_CODE (next) != NOTE)
|
||
break;
|
||
else if (! cross_jump
|
||
&& (NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
|
||
|| NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
|
||
/* ??? Optional. Disables some optimizations, but
|
||
makes gcov output more accurate with -O. */
|
||
|| (flag_test_coverage && NOTE_LINE_NUMBER (next) > 0)))
|
||
break;
|
||
}
|
||
|
||
XEXP (x, 0) = label;
|
||
if (! insn || ! INSN_DELETED_P (insn))
|
||
++LABEL_NUSES (label);
|
||
|
||
if (insn)
|
||
{
|
||
if (GET_CODE (insn) == JUMP_INSN)
|
||
JUMP_LABEL (insn) = label;
|
||
|
||
/* If we've changed OLABEL and we had a REG_LABEL note
|
||
for it, update it as well. */
|
||
else if (label != olabel
|
||
&& (note = find_reg_note (insn, REG_LABEL, olabel)) != 0)
|
||
XEXP (note, 0) = label;
|
||
|
||
/* Otherwise, add a REG_LABEL note for LABEL unless there already
|
||
is one. */
|
||
else if (! find_reg_note (insn, REG_LABEL, label))
|
||
{
|
||
/* This code used to ignore labels which refered to dispatch
|
||
tables to avoid flow.c generating worse code.
|
||
|
||
However, in the presense of global optimizations like
|
||
gcse which call find_basic_blocks without calling
|
||
life_analysis, not recording such labels will lead
|
||
to compiler aborts because of inconsistencies in the
|
||
flow graph. So we go ahead and record the label.
|
||
|
||
It may also be the case that the optimization argument
|
||
is no longer valid because of the more accurate cfg
|
||
we build in find_basic_blocks -- it no longer pessimizes
|
||
code when it finds a REG_LABEL note. */
|
||
REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_LABEL, label,
|
||
REG_NOTES (insn));
|
||
}
|
||
}
|
||
return;
|
||
}
|
||
|
||
/* Do walk the labels in a vector, but not the first operand of an
|
||
ADDR_DIFF_VEC. Don't set the JUMP_LABEL of a vector. */
|
||
case ADDR_VEC:
|
||
case ADDR_DIFF_VEC:
|
||
if (! INSN_DELETED_P (insn))
|
||
{
|
||
int eltnum = code == ADDR_DIFF_VEC ? 1 : 0;
|
||
|
||
for (i = 0; i < XVECLEN (x, eltnum); i++)
|
||
mark_jump_label (XVECEXP (x, eltnum, i), NULL_RTX, cross_jump);
|
||
}
|
||
return;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
mark_jump_label (XEXP (x, i), insn, cross_jump);
|
||
else if (fmt[i] == 'E')
|
||
{
|
||
register int j;
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
mark_jump_label (XVECEXP (x, i, j), insn, cross_jump);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If all INSN does is set the pc, delete it,
|
||
and delete the insn that set the condition codes for it
|
||
if that's what the previous thing was. */
|
||
|
||
void
|
||
delete_jump (insn)
|
||
rtx insn;
|
||
{
|
||
register rtx set = single_set (insn);
|
||
|
||
if (set && GET_CODE (SET_DEST (set)) == PC)
|
||
delete_computation (insn);
|
||
}
|
||
|
||
/* Delete INSN and recursively delete insns that compute values used only
|
||
by INSN. This uses the REG_DEAD notes computed during flow analysis.
|
||
If we are running before flow.c, we need do nothing since flow.c will
|
||
delete dead code. We also can't know if the registers being used are
|
||
dead or not at this point.
|
||
|
||
Otherwise, look at all our REG_DEAD notes. If a previous insn does
|
||
nothing other than set a register that dies in this insn, we can delete
|
||
that insn as well.
|
||
|
||
On machines with CC0, if CC0 is used in this insn, we may be able to
|
||
delete the insn that set it. */
|
||
|
||
static void
|
||
delete_computation (insn)
|
||
rtx insn;
|
||
{
|
||
rtx note, next;
|
||
|
||
#ifdef HAVE_cc0
|
||
if (reg_referenced_p (cc0_rtx, PATTERN (insn)))
|
||
{
|
||
rtx prev = prev_nonnote_insn (insn);
|
||
/* We assume that at this stage
|
||
CC's are always set explicitly
|
||
and always immediately before the jump that
|
||
will use them. So if the previous insn
|
||
exists to set the CC's, delete it
|
||
(unless it performs auto-increments, etc.). */
|
||
if (prev && GET_CODE (prev) == INSN
|
||
&& sets_cc0_p (PATTERN (prev)))
|
||
{
|
||
if (sets_cc0_p (PATTERN (prev)) > 0
|
||
&& !FIND_REG_INC_NOTE (prev, NULL_RTX))
|
||
delete_computation (prev);
|
||
else
|
||
/* Otherwise, show that cc0 won't be used. */
|
||
REG_NOTES (prev) = gen_rtx_EXPR_LIST (REG_UNUSED,
|
||
cc0_rtx, REG_NOTES (prev));
|
||
}
|
||
}
|
||
#endif
|
||
|
||
#ifdef INSN_SCHEDULING
|
||
/* ?!? The schedulers do not keep REG_DEAD notes accurate after
|
||
reload has completed. The schedulers need to be fixed. Until
|
||
they are, we must not rely on the death notes here. */
|
||
if (reload_completed && flag_schedule_insns_after_reload)
|
||
{
|
||
delete_insn (insn);
|
||
return;
|
||
}
|
||
#endif
|
||
|
||
for (note = REG_NOTES (insn); note; note = next)
|
||
{
|
||
rtx our_prev;
|
||
|
||
next = XEXP (note, 1);
|
||
|
||
if (REG_NOTE_KIND (note) != REG_DEAD
|
||
/* Verify that the REG_NOTE is legitimate. */
|
||
|| GET_CODE (XEXP (note, 0)) != REG)
|
||
continue;
|
||
|
||
for (our_prev = prev_nonnote_insn (insn);
|
||
our_prev && GET_CODE (our_prev) == INSN;
|
||
our_prev = prev_nonnote_insn (our_prev))
|
||
{
|
||
/* If we reach a SEQUENCE, it is too complex to try to
|
||
do anything with it, so give up. */
|
||
if (GET_CODE (PATTERN (our_prev)) == SEQUENCE)
|
||
break;
|
||
|
||
if (GET_CODE (PATTERN (our_prev)) == USE
|
||
&& GET_CODE (XEXP (PATTERN (our_prev), 0)) == INSN)
|
||
/* reorg creates USEs that look like this. We leave them
|
||
alone because reorg needs them for its own purposes. */
|
||
break;
|
||
|
||
if (reg_set_p (XEXP (note, 0), PATTERN (our_prev)))
|
||
{
|
||
if (FIND_REG_INC_NOTE (our_prev, NULL_RTX))
|
||
break;
|
||
|
||
if (GET_CODE (PATTERN (our_prev)) == PARALLEL)
|
||
{
|
||
/* If we find a SET of something else, we can't
|
||
delete the insn. */
|
||
|
||
int i;
|
||
|
||
for (i = 0; i < XVECLEN (PATTERN (our_prev), 0); i++)
|
||
{
|
||
rtx part = XVECEXP (PATTERN (our_prev), 0, i);
|
||
|
||
if (GET_CODE (part) == SET
|
||
&& SET_DEST (part) != XEXP (note, 0))
|
||
break;
|
||
}
|
||
|
||
if (i == XVECLEN (PATTERN (our_prev), 0))
|
||
delete_computation (our_prev);
|
||
}
|
||
else if (GET_CODE (PATTERN (our_prev)) == SET
|
||
&& SET_DEST (PATTERN (our_prev)) == XEXP (note, 0))
|
||
delete_computation (our_prev);
|
||
|
||
break;
|
||
}
|
||
|
||
/* If OUR_PREV references the register that dies here, it is an
|
||
additional use. Hence any prior SET isn't dead. However, this
|
||
insn becomes the new place for the REG_DEAD note. */
|
||
if (reg_overlap_mentioned_p (XEXP (note, 0),
|
||
PATTERN (our_prev)))
|
||
{
|
||
XEXP (note, 1) = REG_NOTES (our_prev);
|
||
REG_NOTES (our_prev) = note;
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
delete_insn (insn);
|
||
}
|
||
|
||
/* Delete insn INSN from the chain of insns and update label ref counts.
|
||
May delete some following insns as a consequence; may even delete
|
||
a label elsewhere and insns that follow it.
|
||
|
||
Returns the first insn after INSN that was not deleted. */
|
||
|
||
rtx
|
||
delete_insn (insn)
|
||
register rtx insn;
|
||
{
|
||
register rtx next = NEXT_INSN (insn);
|
||
register rtx prev = PREV_INSN (insn);
|
||
register int was_code_label = (GET_CODE (insn) == CODE_LABEL);
|
||
register int dont_really_delete = 0;
|
||
|
||
while (next && INSN_DELETED_P (next))
|
||
next = NEXT_INSN (next);
|
||
|
||
/* This insn is already deleted => return first following nondeleted. */
|
||
if (INSN_DELETED_P (insn))
|
||
return next;
|
||
|
||
if (was_code_label)
|
||
remove_node_from_expr_list (insn, &nonlocal_goto_handler_labels);
|
||
|
||
/* Don't delete user-declared labels. Convert them to special NOTEs
|
||
instead. */
|
||
if (was_code_label && LABEL_NAME (insn) != 0
|
||
&& optimize && ! dont_really_delete)
|
||
{
|
||
PUT_CODE (insn, NOTE);
|
||
NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED_LABEL;
|
||
NOTE_SOURCE_FILE (insn) = 0;
|
||
dont_really_delete = 1;
|
||
}
|
||
else
|
||
/* Mark this insn as deleted. */
|
||
INSN_DELETED_P (insn) = 1;
|
||
|
||
/* If this is an unconditional jump, delete it from the jump chain. */
|
||
if (simplejump_p (insn))
|
||
delete_from_jump_chain (insn);
|
||
|
||
/* If instruction is followed by a barrier,
|
||
delete the barrier too. */
|
||
|
||
if (next != 0 && GET_CODE (next) == BARRIER)
|
||
{
|
||
INSN_DELETED_P (next) = 1;
|
||
next = NEXT_INSN (next);
|
||
}
|
||
|
||
/* Patch out INSN (and the barrier if any) */
|
||
|
||
if (optimize && ! dont_really_delete)
|
||
{
|
||
if (prev)
|
||
{
|
||
NEXT_INSN (prev) = next;
|
||
if (GET_CODE (prev) == INSN && GET_CODE (PATTERN (prev)) == SEQUENCE)
|
||
NEXT_INSN (XVECEXP (PATTERN (prev), 0,
|
||
XVECLEN (PATTERN (prev), 0) - 1)) = next;
|
||
}
|
||
|
||
if (next)
|
||
{
|
||
PREV_INSN (next) = prev;
|
||
if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
|
||
PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = prev;
|
||
}
|
||
|
||
if (prev && NEXT_INSN (prev) == 0)
|
||
set_last_insn (prev);
|
||
}
|
||
|
||
/* If deleting a jump, decrement the count of the label,
|
||
and delete the label if it is now unused. */
|
||
|
||
if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn))
|
||
{
|
||
rtx lab = JUMP_LABEL (insn), lab_next;
|
||
|
||
if (--LABEL_NUSES (lab) == 0)
|
||
{
|
||
/* This can delete NEXT or PREV,
|
||
either directly if NEXT is JUMP_LABEL (INSN),
|
||
or indirectly through more levels of jumps. */
|
||
delete_insn (lab);
|
||
|
||
/* I feel a little doubtful about this loop,
|
||
but I see no clean and sure alternative way
|
||
to find the first insn after INSN that is not now deleted.
|
||
I hope this works. */
|
||
while (next && INSN_DELETED_P (next))
|
||
next = NEXT_INSN (next);
|
||
return next;
|
||
}
|
||
else if ((lab_next = next_nonnote_insn (lab)) != NULL
|
||
&& GET_CODE (lab_next) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (lab_next)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (lab_next)) == ADDR_DIFF_VEC))
|
||
{
|
||
/* If we're deleting the tablejump, delete the dispatch table.
|
||
We may not be able to kill the label immediately preceeding
|
||
just yet, as it might be referenced in code leading up to
|
||
the tablejump. */
|
||
delete_insn (lab_next);
|
||
}
|
||
}
|
||
|
||
/* Likewise if we're deleting a dispatch table. */
|
||
|
||
if (GET_CODE (insn) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (insn)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
|
||
{
|
||
rtx pat = PATTERN (insn);
|
||
int i, diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC;
|
||
int len = XVECLEN (pat, diff_vec_p);
|
||
|
||
for (i = 0; i < len; i++)
|
||
if (--LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0)) == 0)
|
||
delete_insn (XEXP (XVECEXP (pat, diff_vec_p, i), 0));
|
||
while (next && INSN_DELETED_P (next))
|
||
next = NEXT_INSN (next);
|
||
return next;
|
||
}
|
||
|
||
while (prev && (INSN_DELETED_P (prev) || GET_CODE (prev) == NOTE))
|
||
prev = PREV_INSN (prev);
|
||
|
||
/* If INSN was a label and a dispatch table follows it,
|
||
delete the dispatch table. The tablejump must have gone already.
|
||
It isn't useful to fall through into a table. */
|
||
|
||
if (was_code_label
|
||
&& NEXT_INSN (insn) != 0
|
||
&& GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (NEXT_INSN (insn))) == ADDR_DIFF_VEC))
|
||
next = delete_insn (NEXT_INSN (insn));
|
||
|
||
/* If INSN was a label, delete insns following it if now unreachable. */
|
||
|
||
if (was_code_label && prev && GET_CODE (prev) == BARRIER)
|
||
{
|
||
register RTX_CODE code;
|
||
while (next != 0
|
||
&& (GET_RTX_CLASS (code = GET_CODE (next)) == 'i'
|
||
|| code == NOTE || code == BARRIER
|
||
|| (code == CODE_LABEL && INSN_DELETED_P (next))))
|
||
{
|
||
if (code == NOTE
|
||
&& NOTE_LINE_NUMBER (next) != NOTE_INSN_FUNCTION_END)
|
||
next = NEXT_INSN (next);
|
||
/* Keep going past other deleted labels to delete what follows. */
|
||
else if (code == CODE_LABEL && INSN_DELETED_P (next))
|
||
next = NEXT_INSN (next);
|
||
else
|
||
/* Note: if this deletes a jump, it can cause more
|
||
deletion of unreachable code, after a different label.
|
||
As long as the value from this recursive call is correct,
|
||
this invocation functions correctly. */
|
||
next = delete_insn (next);
|
||
}
|
||
}
|
||
|
||
return next;
|
||
}
|
||
|
||
/* Advance from INSN till reaching something not deleted
|
||
then return that. May return INSN itself. */
|
||
|
||
rtx
|
||
next_nondeleted_insn (insn)
|
||
rtx insn;
|
||
{
|
||
while (INSN_DELETED_P (insn))
|
||
insn = NEXT_INSN (insn);
|
||
return insn;
|
||
}
|
||
|
||
/* Delete a range of insns from FROM to TO, inclusive.
|
||
This is for the sake of peephole optimization, so assume
|
||
that whatever these insns do will still be done by a new
|
||
peephole insn that will replace them. */
|
||
|
||
void
|
||
delete_for_peephole (from, to)
|
||
register rtx from, to;
|
||
{
|
||
register rtx insn = from;
|
||
|
||
while (1)
|
||
{
|
||
register rtx next = NEXT_INSN (insn);
|
||
register rtx prev = PREV_INSN (insn);
|
||
|
||
if (GET_CODE (insn) != NOTE)
|
||
{
|
||
INSN_DELETED_P (insn) = 1;
|
||
|
||
/* Patch this insn out of the chain. */
|
||
/* We don't do this all at once, because we
|
||
must preserve all NOTEs. */
|
||
if (prev)
|
||
NEXT_INSN (prev) = next;
|
||
|
||
if (next)
|
||
PREV_INSN (next) = prev;
|
||
}
|
||
|
||
if (insn == to)
|
||
break;
|
||
insn = next;
|
||
}
|
||
|
||
/* Note that if TO is an unconditional jump
|
||
we *do not* delete the BARRIER that follows,
|
||
since the peephole that replaces this sequence
|
||
is also an unconditional jump in that case. */
|
||
}
|
||
|
||
/* Invert the condition of the jump JUMP, and make it jump
|
||
to label NLABEL instead of where it jumps now. */
|
||
|
||
int
|
||
invert_jump (jump, nlabel)
|
||
rtx jump, nlabel;
|
||
{
|
||
/* We have to either invert the condition and change the label or
|
||
do neither. Either operation could fail. We first try to invert
|
||
the jump. If that succeeds, we try changing the label. If that fails,
|
||
we invert the jump back to what it was. */
|
||
|
||
if (! invert_exp (PATTERN (jump), jump))
|
||
return 0;
|
||
|
||
if (redirect_jump (jump, nlabel))
|
||
{
|
||
if (flag_branch_probabilities)
|
||
{
|
||
rtx note = find_reg_note (jump, REG_BR_PROB, 0);
|
||
|
||
/* An inverted jump means that a probability taken becomes a
|
||
probability not taken. Subtract the branch probability from the
|
||
probability base to convert it back to a taken probability.
|
||
(We don't flip the probability on a branch that's never taken. */
|
||
if (note && XINT (XEXP (note, 0), 0) >= 0)
|
||
XINT (XEXP (note, 0), 0) = REG_BR_PROB_BASE - XINT (XEXP (note, 0), 0);
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
if (! invert_exp (PATTERN (jump), jump))
|
||
/* This should just be putting it back the way it was. */
|
||
abort ();
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Invert the jump condition of rtx X contained in jump insn, INSN.
|
||
|
||
Return 1 if we can do so, 0 if we cannot find a way to do so that
|
||
matches a pattern. */
|
||
|
||
int
|
||
invert_exp (x, insn)
|
||
rtx x;
|
||
rtx insn;
|
||
{
|
||
register RTX_CODE code;
|
||
register int i;
|
||
register char *fmt;
|
||
|
||
code = GET_CODE (x);
|
||
|
||
if (code == IF_THEN_ELSE)
|
||
{
|
||
register rtx comp = XEXP (x, 0);
|
||
register rtx tem;
|
||
|
||
/* We can do this in two ways: The preferable way, which can only
|
||
be done if this is not an integer comparison, is to reverse
|
||
the comparison code. Otherwise, swap the THEN-part and ELSE-part
|
||
of the IF_THEN_ELSE. If we can't do either, fail. */
|
||
|
||
if (can_reverse_comparison_p (comp, insn)
|
||
&& validate_change (insn, &XEXP (x, 0),
|
||
gen_rtx_fmt_ee (reverse_condition (GET_CODE (comp)),
|
||
GET_MODE (comp), XEXP (comp, 0),
|
||
XEXP (comp, 1)), 0))
|
||
return 1;
|
||
|
||
tem = XEXP (x, 1);
|
||
validate_change (insn, &XEXP (x, 1), XEXP (x, 2), 1);
|
||
validate_change (insn, &XEXP (x, 2), tem, 1);
|
||
return apply_change_group ();
|
||
}
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
if (! invert_exp (XEXP (x, i), insn))
|
||
return 0;
|
||
if (fmt[i] == 'E')
|
||
{
|
||
register int j;
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
if (!invert_exp (XVECEXP (x, i, j), insn))
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Make jump JUMP jump to label NLABEL instead of where it jumps now.
|
||
If the old jump target label is unused as a result,
|
||
it and the code following it may be deleted.
|
||
|
||
If NLABEL is zero, we are to turn the jump into a (possibly conditional)
|
||
RETURN insn.
|
||
|
||
The return value will be 1 if the change was made, 0 if it wasn't (this
|
||
can only occur for NLABEL == 0). */
|
||
|
||
int
|
||
redirect_jump (jump, nlabel)
|
||
rtx jump, nlabel;
|
||
{
|
||
register rtx olabel = JUMP_LABEL (jump);
|
||
|
||
if (nlabel == olabel)
|
||
return 1;
|
||
|
||
if (! redirect_exp (&PATTERN (jump), olabel, nlabel, jump))
|
||
return 0;
|
||
|
||
/* If this is an unconditional branch, delete it from the jump_chain of
|
||
OLABEL and add it to the jump_chain of NLABEL (assuming both labels
|
||
have UID's in range and JUMP_CHAIN is valid). */
|
||
if (jump_chain && (simplejump_p (jump)
|
||
|| GET_CODE (PATTERN (jump)) == RETURN))
|
||
{
|
||
int label_index = nlabel ? INSN_UID (nlabel) : 0;
|
||
|
||
delete_from_jump_chain (jump);
|
||
if (label_index < max_jump_chain
|
||
&& INSN_UID (jump) < max_jump_chain)
|
||
{
|
||
jump_chain[INSN_UID (jump)] = jump_chain[label_index];
|
||
jump_chain[label_index] = jump;
|
||
}
|
||
}
|
||
|
||
JUMP_LABEL (jump) = nlabel;
|
||
if (nlabel)
|
||
++LABEL_NUSES (nlabel);
|
||
|
||
if (olabel && --LABEL_NUSES (olabel) == 0)
|
||
delete_insn (olabel);
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Delete the instruction JUMP from any jump chain it might be on. */
|
||
|
||
static void
|
||
delete_from_jump_chain (jump)
|
||
rtx jump;
|
||
{
|
||
int index;
|
||
rtx olabel = JUMP_LABEL (jump);
|
||
|
||
/* Handle unconditional jumps. */
|
||
if (jump_chain && olabel != 0
|
||
&& INSN_UID (olabel) < max_jump_chain
|
||
&& simplejump_p (jump))
|
||
index = INSN_UID (olabel);
|
||
/* Handle return insns. */
|
||
else if (jump_chain && GET_CODE (PATTERN (jump)) == RETURN)
|
||
index = 0;
|
||
else return;
|
||
|
||
if (jump_chain[index] == jump)
|
||
jump_chain[index] = jump_chain[INSN_UID (jump)];
|
||
else
|
||
{
|
||
rtx insn;
|
||
|
||
for (insn = jump_chain[index];
|
||
insn != 0;
|
||
insn = jump_chain[INSN_UID (insn)])
|
||
if (jump_chain[INSN_UID (insn)] == jump)
|
||
{
|
||
jump_chain[INSN_UID (insn)] = jump_chain[INSN_UID (jump)];
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If NLABEL is nonzero, throughout the rtx at LOC,
|
||
alter (LABEL_REF OLABEL) to (LABEL_REF NLABEL). If OLABEL is
|
||
zero, alter (RETURN) to (LABEL_REF NLABEL).
|
||
|
||
If NLABEL is zero, alter (LABEL_REF OLABEL) to (RETURN) and check
|
||
validity with validate_change. Convert (set (pc) (label_ref olabel))
|
||
to (return).
|
||
|
||
Return 0 if we found a change we would like to make but it is invalid.
|
||
Otherwise, return 1. */
|
||
|
||
int
|
||
redirect_exp (loc, olabel, nlabel, insn)
|
||
rtx *loc;
|
||
rtx olabel, nlabel;
|
||
rtx insn;
|
||
{
|
||
register rtx x = *loc;
|
||
register RTX_CODE code = GET_CODE (x);
|
||
register int i;
|
||
register char *fmt;
|
||
|
||
if (code == LABEL_REF)
|
||
{
|
||
if (XEXP (x, 0) == olabel)
|
||
{
|
||
if (nlabel)
|
||
XEXP (x, 0) = nlabel;
|
||
else
|
||
return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
|
||
return 1;
|
||
}
|
||
}
|
||
else if (code == RETURN && olabel == 0)
|
||
{
|
||
x = gen_rtx_LABEL_REF (VOIDmode, nlabel);
|
||
if (loc == &PATTERN (insn))
|
||
x = gen_rtx_SET (VOIDmode, pc_rtx, x);
|
||
return validate_change (insn, loc, x, 0);
|
||
}
|
||
|
||
if (code == SET && nlabel == 0 && SET_DEST (x) == pc_rtx
|
||
&& GET_CODE (SET_SRC (x)) == LABEL_REF
|
||
&& XEXP (SET_SRC (x), 0) == olabel)
|
||
return validate_change (insn, loc, gen_rtx_RETURN (VOIDmode), 0);
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e')
|
||
if (! redirect_exp (&XEXP (x, i), olabel, nlabel, insn))
|
||
return 0;
|
||
if (fmt[i] == 'E')
|
||
{
|
||
register int j;
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
if (! redirect_exp (&XVECEXP (x, i, j), olabel, nlabel, insn))
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Make jump JUMP jump to label NLABEL, assuming it used to be a tablejump.
|
||
|
||
If the old jump target label (before the dispatch table) becomes unused,
|
||
it and the dispatch table may be deleted. In that case, find the insn
|
||
before the jump references that label and delete it and logical successors
|
||
too. */
|
||
|
||
static void
|
||
redirect_tablejump (jump, nlabel)
|
||
rtx jump, nlabel;
|
||
{
|
||
register rtx olabel = JUMP_LABEL (jump);
|
||
|
||
/* Add this jump to the jump_chain of NLABEL. */
|
||
if (jump_chain && INSN_UID (nlabel) < max_jump_chain
|
||
&& INSN_UID (jump) < max_jump_chain)
|
||
{
|
||
jump_chain[INSN_UID (jump)] = jump_chain[INSN_UID (nlabel)];
|
||
jump_chain[INSN_UID (nlabel)] = jump;
|
||
}
|
||
|
||
PATTERN (jump) = gen_jump (nlabel);
|
||
JUMP_LABEL (jump) = nlabel;
|
||
++LABEL_NUSES (nlabel);
|
||
INSN_CODE (jump) = -1;
|
||
|
||
if (--LABEL_NUSES (olabel) == 0)
|
||
{
|
||
delete_labelref_insn (jump, olabel, 0);
|
||
delete_insn (olabel);
|
||
}
|
||
}
|
||
|
||
/* Find the insn referencing LABEL that is a logical predecessor of INSN.
|
||
If we found one, delete it and then delete this insn if DELETE_THIS is
|
||
non-zero. Return non-zero if INSN or a predecessor references LABEL. */
|
||
|
||
static int
|
||
delete_labelref_insn (insn, label, delete_this)
|
||
rtx insn, label;
|
||
int delete_this;
|
||
{
|
||
int deleted = 0;
|
||
rtx link;
|
||
|
||
if (GET_CODE (insn) != NOTE
|
||
&& reg_mentioned_p (label, PATTERN (insn)))
|
||
{
|
||
if (delete_this)
|
||
{
|
||
delete_insn (insn);
|
||
deleted = 1;
|
||
}
|
||
else
|
||
return 1;
|
||
}
|
||
|
||
for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
|
||
if (delete_labelref_insn (XEXP (link, 0), label, 1))
|
||
{
|
||
if (delete_this)
|
||
{
|
||
delete_insn (insn);
|
||
deleted = 1;
|
||
}
|
||
else
|
||
return 1;
|
||
}
|
||
|
||
return deleted;
|
||
}
|
||
|
||
/* Like rtx_equal_p except that it considers two REGs as equal
|
||
if they renumber to the same value and considers two commutative
|
||
operations to be the same if the order of the operands has been
|
||
reversed.
|
||
|
||
??? Addition is not commutative on the PA due to the weird implicit
|
||
space register selection rules for memory addresses. Therefore, we
|
||
don't consider a + b == b + a.
|
||
|
||
We could/should make this test a little tighter. Possibly only
|
||
disabling it on the PA via some backend macro or only disabling this
|
||
case when the PLUS is inside a MEM. */
|
||
|
||
int
|
||
rtx_renumbered_equal_p (x, y)
|
||
rtx x, y;
|
||
{
|
||
register int i;
|
||
register RTX_CODE code = GET_CODE (x);
|
||
register char *fmt;
|
||
|
||
if (x == y)
|
||
return 1;
|
||
|
||
if ((code == REG || (code == SUBREG && GET_CODE (SUBREG_REG (x)) == REG))
|
||
&& (GET_CODE (y) == REG || (GET_CODE (y) == SUBREG
|
||
&& GET_CODE (SUBREG_REG (y)) == REG)))
|
||
{
|
||
int reg_x = -1, reg_y = -1;
|
||
int word_x = 0, word_y = 0;
|
||
|
||
if (GET_MODE (x) != GET_MODE (y))
|
||
return 0;
|
||
|
||
/* If we haven't done any renumbering, don't
|
||
make any assumptions. */
|
||
if (reg_renumber == 0)
|
||
return rtx_equal_p (x, y);
|
||
|
||
if (code == SUBREG)
|
||
{
|
||
reg_x = REGNO (SUBREG_REG (x));
|
||
word_x = SUBREG_WORD (x);
|
||
|
||
if (reg_renumber[reg_x] >= 0)
|
||
{
|
||
reg_x = reg_renumber[reg_x] + word_x;
|
||
word_x = 0;
|
||
}
|
||
}
|
||
|
||
else
|
||
{
|
||
reg_x = REGNO (x);
|
||
if (reg_renumber[reg_x] >= 0)
|
||
reg_x = reg_renumber[reg_x];
|
||
}
|
||
|
||
if (GET_CODE (y) == SUBREG)
|
||
{
|
||
reg_y = REGNO (SUBREG_REG (y));
|
||
word_y = SUBREG_WORD (y);
|
||
|
||
if (reg_renumber[reg_y] >= 0)
|
||
{
|
||
reg_y = reg_renumber[reg_y];
|
||
word_y = 0;
|
||
}
|
||
}
|
||
|
||
else
|
||
{
|
||
reg_y = REGNO (y);
|
||
if (reg_renumber[reg_y] >= 0)
|
||
reg_y = reg_renumber[reg_y];
|
||
}
|
||
|
||
return reg_x >= 0 && reg_x == reg_y && word_x == word_y;
|
||
}
|
||
|
||
/* Now we have disposed of all the cases
|
||
in which different rtx codes can match. */
|
||
if (code != GET_CODE (y))
|
||
return 0;
|
||
|
||
switch (code)
|
||
{
|
||
case PC:
|
||
case CC0:
|
||
case ADDR_VEC:
|
||
case ADDR_DIFF_VEC:
|
||
return 0;
|
||
|
||
case CONST_INT:
|
||
return INTVAL (x) == INTVAL (y);
|
||
|
||
case LABEL_REF:
|
||
/* We can't assume nonlocal labels have their following insns yet. */
|
||
if (LABEL_REF_NONLOCAL_P (x) || LABEL_REF_NONLOCAL_P (y))
|
||
return XEXP (x, 0) == XEXP (y, 0);
|
||
|
||
/* Two label-refs are equivalent if they point at labels
|
||
in the same position in the instruction stream. */
|
||
return (next_real_insn (XEXP (x, 0))
|
||
== next_real_insn (XEXP (y, 0)));
|
||
|
||
case SYMBOL_REF:
|
||
return XSTR (x, 0) == XSTR (y, 0);
|
||
|
||
case CODE_LABEL:
|
||
/* If we didn't match EQ equality above, they aren't the same. */
|
||
return 0;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. */
|
||
|
||
if (GET_MODE (x) != GET_MODE (y))
|
||
return 0;
|
||
|
||
/* For commutative operations, the RTX match if the operand match in any
|
||
order. Also handle the simple binary and unary cases without a loop.
|
||
|
||
??? Don't consider PLUS a commutative operator; see comments above. */
|
||
if ((code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
|
||
&& code != PLUS)
|
||
return ((rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
|
||
&& rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)))
|
||
|| (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 1))
|
||
&& rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 0))));
|
||
else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
|
||
return (rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0))
|
||
&& rtx_renumbered_equal_p (XEXP (x, 1), XEXP (y, 1)));
|
||
else if (GET_RTX_CLASS (code) == '1')
|
||
return rtx_renumbered_equal_p (XEXP (x, 0), XEXP (y, 0));
|
||
|
||
/* Compare the elements. If any pair of corresponding elements
|
||
fail to match, return 0 for the whole things. */
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
register int j;
|
||
switch (fmt[i])
|
||
{
|
||
case 'w':
|
||
if (XWINT (x, i) != XWINT (y, i))
|
||
return 0;
|
||
break;
|
||
|
||
case 'i':
|
||
if (XINT (x, i) != XINT (y, i))
|
||
return 0;
|
||
break;
|
||
|
||
case 's':
|
||
if (strcmp (XSTR (x, i), XSTR (y, i)))
|
||
return 0;
|
||
break;
|
||
|
||
case 'e':
|
||
if (! rtx_renumbered_equal_p (XEXP (x, i), XEXP (y, i)))
|
||
return 0;
|
||
break;
|
||
|
||
case 'u':
|
||
if (XEXP (x, i) != XEXP (y, i))
|
||
return 0;
|
||
/* fall through. */
|
||
case '0':
|
||
break;
|
||
|
||
case 'E':
|
||
if (XVECLEN (x, i) != XVECLEN (y, i))
|
||
return 0;
|
||
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
|
||
if (!rtx_renumbered_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)))
|
||
return 0;
|
||
break;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
return 1;
|
||
}
|
||
|
||
/* If X is a hard register or equivalent to one or a subregister of one,
|
||
return the hard register number. If X is a pseudo register that was not
|
||
assigned a hard register, return the pseudo register number. Otherwise,
|
||
return -1. Any rtx is valid for X. */
|
||
|
||
int
|
||
true_regnum (x)
|
||
rtx x;
|
||
{
|
||
if (GET_CODE (x) == REG)
|
||
{
|
||
if (REGNO (x) >= FIRST_PSEUDO_REGISTER && reg_renumber[REGNO (x)] >= 0)
|
||
return reg_renumber[REGNO (x)];
|
||
return REGNO (x);
|
||
}
|
||
if (GET_CODE (x) == SUBREG)
|
||
{
|
||
int base = true_regnum (SUBREG_REG (x));
|
||
if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
|
||
return SUBREG_WORD (x) + base;
|
||
}
|
||
return -1;
|
||
}
|
||
|
||
/* Optimize code of the form:
|
||
|
||
for (x = a[i]; x; ...)
|
||
...
|
||
for (x = a[i]; x; ...)
|
||
...
|
||
foo:
|
||
|
||
Loop optimize will change the above code into
|
||
|
||
if (x = a[i])
|
||
for (;;)
|
||
{ ...; if (! (x = ...)) break; }
|
||
if (x = a[i])
|
||
for (;;)
|
||
{ ...; if (! (x = ...)) break; }
|
||
foo:
|
||
|
||
In general, if the first test fails, the program can branch
|
||
directly to `foo' and skip the second try which is doomed to fail.
|
||
We run this after loop optimization and before flow analysis. */
|
||
|
||
/* When comparing the insn patterns, we track the fact that different
|
||
pseudo-register numbers may have been used in each computation.
|
||
The following array stores an equivalence -- same_regs[I] == J means
|
||
that pseudo register I was used in the first set of tests in a context
|
||
where J was used in the second set. We also count the number of such
|
||
pending equivalences. If nonzero, the expressions really aren't the
|
||
same. */
|
||
|
||
static int *same_regs;
|
||
|
||
static int num_same_regs;
|
||
|
||
/* Track any registers modified between the target of the first jump and
|
||
the second jump. They never compare equal. */
|
||
|
||
static char *modified_regs;
|
||
|
||
/* Record if memory was modified. */
|
||
|
||
static int modified_mem;
|
||
|
||
/* Called via note_stores on each insn between the target of the first
|
||
branch and the second branch. It marks any changed registers. */
|
||
|
||
static void
|
||
mark_modified_reg (dest, x)
|
||
rtx dest;
|
||
rtx x ATTRIBUTE_UNUSED;
|
||
{
|
||
int regno, i;
|
||
|
||
if (GET_CODE (dest) == SUBREG)
|
||
dest = SUBREG_REG (dest);
|
||
|
||
if (GET_CODE (dest) == MEM)
|
||
modified_mem = 1;
|
||
|
||
if (GET_CODE (dest) != REG)
|
||
return;
|
||
|
||
regno = REGNO (dest);
|
||
if (regno >= FIRST_PSEUDO_REGISTER)
|
||
modified_regs[regno] = 1;
|
||
else
|
||
for (i = 0; i < HARD_REGNO_NREGS (regno, GET_MODE (dest)); i++)
|
||
modified_regs[regno + i] = 1;
|
||
}
|
||
|
||
/* F is the first insn in the chain of insns. */
|
||
|
||
void
|
||
thread_jumps (f, max_reg, flag_before_loop)
|
||
rtx f;
|
||
int max_reg;
|
||
int flag_before_loop;
|
||
{
|
||
/* Basic algorithm is to find a conditional branch,
|
||
the label it may branch to, and the branch after
|
||
that label. If the two branches test the same condition,
|
||
walk back from both branch paths until the insn patterns
|
||
differ, or code labels are hit. If we make it back to
|
||
the target of the first branch, then we know that the first branch
|
||
will either always succeed or always fail depending on the relative
|
||
senses of the two branches. So adjust the first branch accordingly
|
||
in this case. */
|
||
|
||
rtx label, b1, b2, t1, t2;
|
||
enum rtx_code code1, code2;
|
||
rtx b1op0, b1op1, b2op0, b2op1;
|
||
int changed = 1;
|
||
int i;
|
||
int *all_reset;
|
||
|
||
/* Allocate register tables and quick-reset table. */
|
||
modified_regs = (char *) alloca (max_reg * sizeof (char));
|
||
same_regs = (int *) alloca (max_reg * sizeof (int));
|
||
all_reset = (int *) alloca (max_reg * sizeof (int));
|
||
for (i = 0; i < max_reg; i++)
|
||
all_reset[i] = -1;
|
||
|
||
while (changed)
|
||
{
|
||
changed = 0;
|
||
|
||
for (b1 = f; b1; b1 = NEXT_INSN (b1))
|
||
{
|
||
/* Get to a candidate branch insn. */
|
||
if (GET_CODE (b1) != JUMP_INSN
|
||
|| ! condjump_p (b1) || simplejump_p (b1)
|
||
|| JUMP_LABEL (b1) == 0)
|
||
continue;
|
||
|
||
bzero (modified_regs, max_reg * sizeof (char));
|
||
modified_mem = 0;
|
||
|
||
bcopy ((char *) all_reset, (char *) same_regs,
|
||
max_reg * sizeof (int));
|
||
num_same_regs = 0;
|
||
|
||
label = JUMP_LABEL (b1);
|
||
|
||
/* Look for a branch after the target. Record any registers and
|
||
memory modified between the target and the branch. Stop when we
|
||
get to a label since we can't know what was changed there. */
|
||
for (b2 = NEXT_INSN (label); b2; b2 = NEXT_INSN (b2))
|
||
{
|
||
if (GET_CODE (b2) == CODE_LABEL)
|
||
break;
|
||
|
||
else if (GET_CODE (b2) == JUMP_INSN)
|
||
{
|
||
/* If this is an unconditional jump and is the only use of
|
||
its target label, we can follow it. */
|
||
if (simplejump_p (b2)
|
||
&& JUMP_LABEL (b2) != 0
|
||
&& LABEL_NUSES (JUMP_LABEL (b2)) == 1)
|
||
{
|
||
b2 = JUMP_LABEL (b2);
|
||
continue;
|
||
}
|
||
else
|
||
break;
|
||
}
|
||
|
||
if (GET_CODE (b2) != CALL_INSN && GET_CODE (b2) != INSN)
|
||
continue;
|
||
|
||
if (GET_CODE (b2) == CALL_INSN)
|
||
{
|
||
modified_mem = 1;
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (call_used_regs[i] && ! fixed_regs[i]
|
||
&& i != STACK_POINTER_REGNUM
|
||
&& i != FRAME_POINTER_REGNUM
|
||
&& i != HARD_FRAME_POINTER_REGNUM
|
||
&& i != ARG_POINTER_REGNUM)
|
||
modified_regs[i] = 1;
|
||
}
|
||
|
||
note_stores (PATTERN (b2), mark_modified_reg);
|
||
}
|
||
|
||
/* Check the next candidate branch insn from the label
|
||
of the first. */
|
||
if (b2 == 0
|
||
|| GET_CODE (b2) != JUMP_INSN
|
||
|| b2 == b1
|
||
|| ! condjump_p (b2)
|
||
|| simplejump_p (b2))
|
||
continue;
|
||
|
||
/* Get the comparison codes and operands, reversing the
|
||
codes if appropriate. If we don't have comparison codes,
|
||
we can't do anything. */
|
||
b1op0 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 0);
|
||
b1op1 = XEXP (XEXP (SET_SRC (PATTERN (b1)), 0), 1);
|
||
code1 = GET_CODE (XEXP (SET_SRC (PATTERN (b1)), 0));
|
||
if (XEXP (SET_SRC (PATTERN (b1)), 1) == pc_rtx)
|
||
code1 = reverse_condition (code1);
|
||
|
||
b2op0 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 0);
|
||
b2op1 = XEXP (XEXP (SET_SRC (PATTERN (b2)), 0), 1);
|
||
code2 = GET_CODE (XEXP (SET_SRC (PATTERN (b2)), 0));
|
||
if (XEXP (SET_SRC (PATTERN (b2)), 1) == pc_rtx)
|
||
code2 = reverse_condition (code2);
|
||
|
||
/* If they test the same things and knowing that B1 branches
|
||
tells us whether or not B2 branches, check if we
|
||
can thread the branch. */
|
||
if (rtx_equal_for_thread_p (b1op0, b2op0, b2)
|
||
&& rtx_equal_for_thread_p (b1op1, b2op1, b2)
|
||
&& (comparison_dominates_p (code1, code2)
|
||
|| (comparison_dominates_p (code1, reverse_condition (code2))
|
||
&& can_reverse_comparison_p (XEXP (SET_SRC (PATTERN (b1)),
|
||
0),
|
||
b1))))
|
||
{
|
||
t1 = prev_nonnote_insn (b1);
|
||
t2 = prev_nonnote_insn (b2);
|
||
|
||
while (t1 != 0 && t2 != 0)
|
||
{
|
||
if (t2 == label)
|
||
{
|
||
/* We have reached the target of the first branch.
|
||
If there are no pending register equivalents,
|
||
we know that this branch will either always
|
||
succeed (if the senses of the two branches are
|
||
the same) or always fail (if not). */
|
||
rtx new_label;
|
||
|
||
if (num_same_regs != 0)
|
||
break;
|
||
|
||
if (comparison_dominates_p (code1, code2))
|
||
new_label = JUMP_LABEL (b2);
|
||
else
|
||
new_label = get_label_after (b2);
|
||
|
||
if (JUMP_LABEL (b1) != new_label)
|
||
{
|
||
rtx prev = PREV_INSN (new_label);
|
||
|
||
if (flag_before_loop
|
||
&& GET_CODE (prev) == NOTE
|
||
&& NOTE_LINE_NUMBER (prev) == NOTE_INSN_LOOP_BEG)
|
||
{
|
||
/* Don't thread to the loop label. If a loop
|
||
label is reused, loop optimization will
|
||
be disabled for that loop. */
|
||
new_label = gen_label_rtx ();
|
||
emit_label_after (new_label, PREV_INSN (prev));
|
||
}
|
||
changed |= redirect_jump (b1, new_label);
|
||
}
|
||
break;
|
||
}
|
||
|
||
/* If either of these is not a normal insn (it might be
|
||
a JUMP_INSN, CALL_INSN, or CODE_LABEL) we fail. (NOTEs
|
||
have already been skipped above.) Similarly, fail
|
||
if the insns are different. */
|
||
if (GET_CODE (t1) != INSN || GET_CODE (t2) != INSN
|
||
|| recog_memoized (t1) != recog_memoized (t2)
|
||
|| ! rtx_equal_for_thread_p (PATTERN (t1),
|
||
PATTERN (t2), t2))
|
||
break;
|
||
|
||
t1 = prev_nonnote_insn (t1);
|
||
t2 = prev_nonnote_insn (t2);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* This is like RTX_EQUAL_P except that it knows about our handling of
|
||
possibly equivalent registers and knows to consider volatile and
|
||
modified objects as not equal.
|
||
|
||
YINSN is the insn containing Y. */
|
||
|
||
int
|
||
rtx_equal_for_thread_p (x, y, yinsn)
|
||
rtx x, y;
|
||
rtx yinsn;
|
||
{
|
||
register int i;
|
||
register int j;
|
||
register enum rtx_code code;
|
||
register char *fmt;
|
||
|
||
code = GET_CODE (x);
|
||
/* Rtx's of different codes cannot be equal. */
|
||
if (code != GET_CODE (y))
|
||
return 0;
|
||
|
||
/* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
|
||
(REG:SI x) and (REG:HI x) are NOT equivalent. */
|
||
|
||
if (GET_MODE (x) != GET_MODE (y))
|
||
return 0;
|
||
|
||
/* For floating-point, consider everything unequal. This is a bit
|
||
pessimistic, but this pass would only rarely do anything for FP
|
||
anyway. */
|
||
if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
|
||
&& FLOAT_MODE_P (GET_MODE (x)) && ! flag_fast_math)
|
||
return 0;
|
||
|
||
/* For commutative operations, the RTX match if the operand match in any
|
||
order. Also handle the simple binary and unary cases without a loop. */
|
||
if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
|
||
return ((rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
|
||
&& rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn))
|
||
|| (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 1), yinsn)
|
||
&& rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 0), yinsn)));
|
||
else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
|
||
return (rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn)
|
||
&& rtx_equal_for_thread_p (XEXP (x, 1), XEXP (y, 1), yinsn));
|
||
else if (GET_RTX_CLASS (code) == '1')
|
||
return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
|
||
|
||
/* Handle special-cases first. */
|
||
switch (code)
|
||
{
|
||
case REG:
|
||
if (REGNO (x) == REGNO (y) && ! modified_regs[REGNO (x)])
|
||
return 1;
|
||
|
||
/* If neither is user variable or hard register, check for possible
|
||
equivalence. */
|
||
if (REG_USERVAR_P (x) || REG_USERVAR_P (y)
|
||
|| REGNO (x) < FIRST_PSEUDO_REGISTER
|
||
|| REGNO (y) < FIRST_PSEUDO_REGISTER)
|
||
return 0;
|
||
|
||
if (same_regs[REGNO (x)] == -1)
|
||
{
|
||
same_regs[REGNO (x)] = REGNO (y);
|
||
num_same_regs++;
|
||
|
||
/* If this is the first time we are seeing a register on the `Y'
|
||
side, see if it is the last use. If not, we can't thread the
|
||
jump, so mark it as not equivalent. */
|
||
if (REGNO_LAST_UID (REGNO (y)) != INSN_UID (yinsn))
|
||
return 0;
|
||
|
||
return 1;
|
||
}
|
||
else
|
||
return (same_regs[REGNO (x)] == REGNO (y));
|
||
|
||
break;
|
||
|
||
case MEM:
|
||
/* If memory modified or either volatile, not equivalent.
|
||
Else, check address. */
|
||
if (modified_mem || MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
|
||
return 0;
|
||
|
||
return rtx_equal_for_thread_p (XEXP (x, 0), XEXP (y, 0), yinsn);
|
||
|
||
case ASM_INPUT:
|
||
if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y))
|
||
return 0;
|
||
|
||
break;
|
||
|
||
case SET:
|
||
/* Cancel a pending `same_regs' if setting equivalenced registers.
|
||
Then process source. */
|
||
if (GET_CODE (SET_DEST (x)) == REG
|
||
&& GET_CODE (SET_DEST (y)) == REG)
|
||
{
|
||
if (same_regs[REGNO (SET_DEST (x))] == REGNO (SET_DEST (y)))
|
||
{
|
||
same_regs[REGNO (SET_DEST (x))] = -1;
|
||
num_same_regs--;
|
||
}
|
||
else if (REGNO (SET_DEST (x)) != REGNO (SET_DEST (y)))
|
||
return 0;
|
||
}
|
||
else
|
||
if (rtx_equal_for_thread_p (SET_DEST (x), SET_DEST (y), yinsn) == 0)
|
||
return 0;
|
||
|
||
return rtx_equal_for_thread_p (SET_SRC (x), SET_SRC (y), yinsn);
|
||
|
||
case LABEL_REF:
|
||
return XEXP (x, 0) == XEXP (y, 0);
|
||
|
||
case SYMBOL_REF:
|
||
return XSTR (x, 0) == XSTR (y, 0);
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
if (x == y)
|
||
return 1;
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
switch (fmt[i])
|
||
{
|
||
case 'w':
|
||
if (XWINT (x, i) != XWINT (y, i))
|
||
return 0;
|
||
break;
|
||
|
||
case 'n':
|
||
case 'i':
|
||
if (XINT (x, i) != XINT (y, i))
|
||
return 0;
|
||
break;
|
||
|
||
case 'V':
|
||
case 'E':
|
||
/* Two vectors must have the same length. */
|
||
if (XVECLEN (x, i) != XVECLEN (y, i))
|
||
return 0;
|
||
|
||
/* And the corresponding elements must match. */
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
if (rtx_equal_for_thread_p (XVECEXP (x, i, j),
|
||
XVECEXP (y, i, j), yinsn) == 0)
|
||
return 0;
|
||
break;
|
||
|
||
case 'e':
|
||
if (rtx_equal_for_thread_p (XEXP (x, i), XEXP (y, i), yinsn) == 0)
|
||
return 0;
|
||
break;
|
||
|
||
case 'S':
|
||
case 's':
|
||
if (strcmp (XSTR (x, i), XSTR (y, i)))
|
||
return 0;
|
||
break;
|
||
|
||
case 'u':
|
||
/* These are just backpointers, so they don't matter. */
|
||
break;
|
||
|
||
case '0':
|
||
break;
|
||
|
||
/* It is believed that rtx's at this level will never
|
||
contain anything but integers and other rtx's,
|
||
except for within LABEL_REFs and SYMBOL_REFs. */
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
return 1;
|
||
}
|
||
|
||
|
||
#ifndef HAVE_cc0
|
||
/* Return the insn that NEW can be safely inserted in front of starting at
|
||
the jump insn INSN. Return 0 if it is not safe to do this jump
|
||
optimization. Note that NEW must contain a single set. */
|
||
|
||
static rtx
|
||
find_insert_position (insn, new)
|
||
rtx insn;
|
||
rtx new;
|
||
{
|
||
int i;
|
||
rtx prev;
|
||
|
||
/* If NEW does not clobber, it is safe to insert NEW before INSN. */
|
||
if (GET_CODE (PATTERN (new)) != PARALLEL)
|
||
return insn;
|
||
|
||
for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
|
||
if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
|
||
&& reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
|
||
insn))
|
||
break;
|
||
|
||
if (i < 0)
|
||
return insn;
|
||
|
||
/* There is a good chance that the previous insn PREV sets the thing
|
||
being clobbered (often the CC in a hard reg). If PREV does not
|
||
use what NEW sets, we can insert NEW before PREV. */
|
||
|
||
prev = prev_active_insn (insn);
|
||
for (i = XVECLEN (PATTERN (new), 0) - 1; i >= 0; i--)
|
||
if (GET_CODE (XVECEXP (PATTERN (new), 0, i)) == CLOBBER
|
||
&& reg_overlap_mentioned_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
|
||
insn)
|
||
&& ! modified_in_p (XEXP (XVECEXP (PATTERN (new), 0, i), 0),
|
||
prev))
|
||
return 0;
|
||
|
||
return reg_mentioned_p (SET_DEST (single_set (new)), prev) ? 0 : prev;
|
||
}
|
||
#endif /* !HAVE_cc0 */
|