1522 lines
42 KiB
C
1522 lines
42 KiB
C
/* Reassociation for trees.
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Copyright (C) 2005 Free Software Foundation, Inc.
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Contributed by Daniel Berlin <dan@dberlin.org>
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This file is part of GCC.
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GCC 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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GCC 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 GCC; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "errors.h"
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#include "ggc.h"
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#include "tree.h"
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#include "basic-block.h"
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#include "diagnostic.h"
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#include "tree-inline.h"
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#include "tree-flow.h"
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#include "tree-gimple.h"
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#include "tree-dump.h"
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#include "timevar.h"
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#include "tree-iterator.h"
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#include "tree-pass.h"
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#include "alloc-pool.h"
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#include "vec.h"
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#include "langhooks.h"
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/* This is a simple global reassociation pass. It is, in part, based
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on the LLVM pass of the same name (They do some things more/less
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than we do, in different orders, etc).
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It consists of five steps:
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1. Breaking up subtract operations into addition + negate, where
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it would promote the reassociation of adds.
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2. Left linearization of the expression trees, so that (A+B)+(C+D)
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becomes (((A+B)+C)+D), which is easier for us to rewrite later.
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During linearization, we place the operands of the binary
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expressions into a vector of operand_entry_t
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3. Optimization of the operand lists, eliminating things like a +
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-a, a & a, etc.
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4. Rewrite the expression trees we linearized and optimized so
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they are in proper rank order.
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5. Repropagate negates, as nothing else will clean it up ATM.
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A bit of theory on #4, since nobody seems to write anything down
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about why it makes sense to do it the way they do it:
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We could do this much nicer theoretically, but don't (for reasons
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explained after how to do it theoretically nice :P).
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In order to promote the most redundancy elimination, you want
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binary expressions whose operands are the same rank (or
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preferably, the same value) exposed to the redundancy eliminator,
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for possible elimination.
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So the way to do this if we really cared, is to build the new op
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tree from the leaves to the roots, merging as you go, and putting the
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new op on the end of the worklist, until you are left with one
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thing on the worklist.
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IE if you have to rewrite the following set of operands (listed with
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rank in parentheses), with opcode PLUS_EXPR:
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a (1), b (1), c (1), d (2), e (2)
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We start with our merge worklist empty, and the ops list with all of
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those on it.
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You want to first merge all leaves of the same rank, as much as
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possible.
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So first build a binary op of
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mergetmp = a + b, and put "mergetmp" on the merge worklist.
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Because there is no three operand form of PLUS_EXPR, c is not going to
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be exposed to redundancy elimination as a rank 1 operand.
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So you might as well throw it on the merge worklist (you could also
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consider it to now be a rank two operand, and merge it with d and e,
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but in this case, you then have evicted e from a binary op. So at
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least in this situation, you can't win.)
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Then build a binary op of d + e
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mergetmp2 = d + e
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and put mergetmp2 on the merge worklist.
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so merge worklist = {mergetmp, c, mergetmp2}
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Continue building binary ops of these operations until you have only
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one operation left on the worklist.
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So we have
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build binary op
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mergetmp3 = mergetmp + c
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worklist = {mergetmp2, mergetmp3}
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mergetmp4 = mergetmp2 + mergetmp3
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worklist = {mergetmp4}
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because we have one operation left, we can now just set the original
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statement equal to the result of that operation.
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This will at least expose a + b and d + e to redundancy elimination
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as binary operations.
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For extra points, you can reuse the old statements to build the
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mergetmps, since you shouldn't run out.
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So why don't we do this?
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Because it's expensive, and rarely will help. Most trees we are
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reassociating have 3 or less ops. If they have 2 ops, they already
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will be written into a nice single binary op. If you have 3 ops, a
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single simple check suffices to tell you whether the first two are of the
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same rank. If so, you know to order it
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mergetmp = op1 + op2
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newstmt = mergetmp + op3
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instead of
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mergetmp = op2 + op3
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newstmt = mergetmp + op1
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If all three are of the same rank, you can't expose them all in a
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single binary operator anyway, so the above is *still* the best you
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can do.
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Thus, this is what we do. When we have three ops left, we check to see
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what order to put them in, and call it a day. As a nod to vector sum
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reduction, we check if any of ops are a really a phi node that is a
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destructive update for the associating op, and keep the destructive
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update together for vector sum reduction recognition. */
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/* Statistics */
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static struct
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{
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int linearized;
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int constants_eliminated;
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int ops_eliminated;
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int rewritten;
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} reassociate_stats;
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/* Operator, rank pair. */
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typedef struct operand_entry
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{
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unsigned int rank;
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tree op;
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} *operand_entry_t;
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static alloc_pool operand_entry_pool;
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/* Starting rank number for a given basic block, so that we can rank
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operations using unmovable instructions in that BB based on the bb
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depth. */
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static unsigned int *bb_rank;
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/* Operand->rank hashtable. */
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static htab_t operand_rank;
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/* Look up the operand rank structure for expression E. */
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static operand_entry_t
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find_operand_rank (tree e)
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{
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void **slot;
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struct operand_entry vrd;
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vrd.op = e;
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slot = htab_find_slot (operand_rank, &vrd, NO_INSERT);
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if (!slot)
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return NULL;
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return ((operand_entry_t) *slot);
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}
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/* Insert {E,RANK} into the operand rank hashtable. */
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static void
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insert_operand_rank (tree e, unsigned int rank)
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{
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void **slot;
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operand_entry_t new_pair = pool_alloc (operand_entry_pool);
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new_pair->op = e;
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new_pair->rank = rank;
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slot = htab_find_slot (operand_rank, new_pair, INSERT);
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gcc_assert (*slot == NULL);
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*slot = new_pair;
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}
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/* Return the hash value for a operand rank structure */
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static hashval_t
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operand_entry_hash (const void *p)
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{
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const operand_entry_t vr = (operand_entry_t) p;
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return iterative_hash_expr (vr->op, 0);
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}
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/* Return true if two operand rank structures are equal. */
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static int
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operand_entry_eq (const void *p1, const void *p2)
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{
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const operand_entry_t vr1 = (operand_entry_t) p1;
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const operand_entry_t vr2 = (operand_entry_t) p2;
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return vr1->op == vr2->op;
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}
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/* Given an expression E, return the rank of the expression. */
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static unsigned int
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get_rank (tree e)
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{
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operand_entry_t vr;
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/* Constants have rank 0. */
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if (is_gimple_min_invariant (e))
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return 0;
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/* SSA_NAME's have the rank of the expression they are the result
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of.
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For globals and uninitialized values, the rank is 0.
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For function arguments, use the pre-setup rank.
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For PHI nodes, stores, asm statements, etc, we use the rank of
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the BB.
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For simple operations, the rank is the maximum rank of any of
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its operands, or the bb_rank, whichever is less.
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I make no claims that this is optimal, however, it gives good
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results. */
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if (TREE_CODE (e) == SSA_NAME)
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{
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tree stmt;
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tree rhs;
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unsigned int rank, maxrank;
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int i;
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if (TREE_CODE (SSA_NAME_VAR (e)) == PARM_DECL
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&& e == default_def (SSA_NAME_VAR (e)))
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return find_operand_rank (e)->rank;
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stmt = SSA_NAME_DEF_STMT (e);
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if (bb_for_stmt (stmt) == NULL)
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return 0;
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if (TREE_CODE (stmt) != MODIFY_EXPR
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|| !ZERO_SSA_OPERANDS (stmt, SSA_OP_VIRTUAL_DEFS))
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return bb_rank[bb_for_stmt (stmt)->index];
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/* If we already have a rank for this expression, use that. */
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vr = find_operand_rank (e);
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if (vr)
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return vr->rank;
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/* Otherwise, find the maximum rank for the operands, or the bb
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rank, whichever is less. */
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rank = 0;
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maxrank = bb_rank[bb_for_stmt(stmt)->index];
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rhs = TREE_OPERAND (stmt, 1);
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if (TREE_CODE_LENGTH (TREE_CODE (rhs)) == 0)
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rank = MAX (rank, get_rank (rhs));
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else
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{
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for (i = 0;
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i < TREE_CODE_LENGTH (TREE_CODE (rhs))
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&& TREE_OPERAND (rhs, i)
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&& rank != maxrank;
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i++)
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rank = MAX(rank, get_rank (TREE_OPERAND (rhs, i)));
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}
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if (dump_file && (dump_flags & TDF_DETAILS))
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{
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fprintf (dump_file, "Rank for ");
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print_generic_expr (dump_file, e, 0);
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fprintf (dump_file, " is %d\n", (rank + 1));
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}
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/* Note the rank in the hashtable so we don't recompute it. */
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insert_operand_rank (e, (rank + 1));
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return (rank + 1);
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}
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/* Globals, etc, are rank 0 */
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return 0;
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}
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DEF_VEC_P(operand_entry_t);
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DEF_VEC_ALLOC_P(operand_entry_t, heap);
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/* We want integer ones to end up last no matter what, since they are
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the ones we can do the most with. */
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#define INTEGER_CONST_TYPE 1 << 3
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#define FLOAT_CONST_TYPE 1 << 2
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#define OTHER_CONST_TYPE 1 << 1
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/* Classify an invariant tree into integer, float, or other, so that
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we can sort them to be near other constants of the same type. */
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static inline int
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constant_type (tree t)
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{
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if (INTEGRAL_TYPE_P (TREE_TYPE (t)))
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return INTEGER_CONST_TYPE;
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else if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (t)))
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return FLOAT_CONST_TYPE;
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else
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return OTHER_CONST_TYPE;
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}
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/* qsort comparison function to sort operand entries PA and PB by rank
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so that the sorted array is ordered by rank in decreasing order. */
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static int
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sort_by_operand_rank (const void *pa, const void *pb)
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{
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const operand_entry_t oea = *(const operand_entry_t *)pa;
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const operand_entry_t oeb = *(const operand_entry_t *)pb;
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/* It's nicer for optimize_expression if constants that are likely
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to fold when added/multiplied//whatever are put next to each
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other. Since all constants have rank 0, order them by type. */
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if (oeb->rank == 0 && oea->rank == 0)
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return constant_type (oeb->op) - constant_type (oea->op);
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/* Lastly, make sure the versions that are the same go next to each
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other. We use SSA_NAME_VERSION because it's stable. */
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if ((oeb->rank - oea->rank == 0)
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&& TREE_CODE (oea->op) == SSA_NAME
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&& TREE_CODE (oeb->op) == SSA_NAME)
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return SSA_NAME_VERSION (oeb->op) - SSA_NAME_VERSION (oea->op);
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return oeb->rank - oea->rank;
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}
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/* Add an operand entry to *OPS for the tree operand OP. */
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static void
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add_to_ops_vec (VEC(operand_entry_t, heap) **ops, tree op)
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{
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operand_entry_t oe = pool_alloc (operand_entry_pool);
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oe->op = op;
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oe->rank = get_rank (op);
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VEC_safe_push (operand_entry_t, heap, *ops, oe);
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}
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/* Return true if STMT is reassociable operation containing a binary
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operation with tree code CODE. */
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static bool
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is_reassociable_op (tree stmt, enum tree_code code)
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{
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if (!IS_EMPTY_STMT (stmt)
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&& TREE_CODE (stmt) == MODIFY_EXPR
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&& TREE_CODE (TREE_OPERAND (stmt, 1)) == code
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&& has_single_use (TREE_OPERAND (stmt, 0)))
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return true;
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return false;
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}
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/* Given NAME, if NAME is defined by a unary operation OPCODE, return the
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operand of the negate operation. Otherwise, return NULL. */
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static tree
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get_unary_op (tree name, enum tree_code opcode)
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{
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tree stmt = SSA_NAME_DEF_STMT (name);
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tree rhs;
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if (TREE_CODE (stmt) != MODIFY_EXPR)
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return NULL_TREE;
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rhs = TREE_OPERAND (stmt, 1);
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if (TREE_CODE (rhs) == opcode)
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return TREE_OPERAND (rhs, 0);
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return NULL_TREE;
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}
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/* If CURR and LAST are a pair of ops that OPCODE allows us to
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eliminate through equivalences, do so, remove them from OPS, and
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return true. Otherwise, return false. */
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static bool
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eliminate_duplicate_pair (enum tree_code opcode,
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VEC (operand_entry_t, heap) **ops,
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bool *all_done,
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unsigned int i,
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operand_entry_t curr,
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operand_entry_t last)
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{
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/* If we have two of the same op, and the opcode is & |, min, or max,
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we can eliminate one of them.
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If we have two of the same op, and the opcode is ^, we can
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eliminate both of them. */
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if (last && last->op == curr->op)
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{
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switch (opcode)
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{
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case MAX_EXPR:
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case MIN_EXPR:
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case BIT_IOR_EXPR:
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case BIT_AND_EXPR:
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if (dump_file && (dump_flags & TDF_DETAILS))
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{
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fprintf (dump_file, "Equivalence: ");
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print_generic_expr (dump_file, curr->op, 0);
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fprintf (dump_file, " [&|minmax] ");
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print_generic_expr (dump_file, last->op, 0);
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fprintf (dump_file, " -> ");
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print_generic_stmt (dump_file, last->op, 0);
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}
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VEC_ordered_remove (operand_entry_t, *ops, i);
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reassociate_stats.ops_eliminated ++;
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return true;
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case BIT_XOR_EXPR:
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if (dump_file && (dump_flags & TDF_DETAILS))
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{
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fprintf (dump_file, "Equivalence: ");
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print_generic_expr (dump_file, curr->op, 0);
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fprintf (dump_file, " ^ ");
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print_generic_expr (dump_file, last->op, 0);
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fprintf (dump_file, " -> nothing\n");
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}
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reassociate_stats.ops_eliminated += 2;
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if (VEC_length (operand_entry_t, *ops) == 2)
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{
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VEC_free (operand_entry_t, heap, *ops);
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*ops = NULL;
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add_to_ops_vec (ops, fold_convert (TREE_TYPE (last->op),
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integer_zero_node));
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*all_done = true;
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}
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else
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{
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VEC_ordered_remove (operand_entry_t, *ops, i-1);
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VEC_ordered_remove (operand_entry_t, *ops, i-1);
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}
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return true;
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default:
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break;
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}
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}
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return false;
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}
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/* If OPCODE is PLUS_EXPR, CURR->OP is really a negate expression,
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look in OPS for a corresponding positive operation to cancel it
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out. If we find one, remove the other from OPS, replace
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OPS[CURRINDEX] with 0, and return true. Otherwise, return
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false. */
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static bool
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eliminate_plus_minus_pair (enum tree_code opcode,
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VEC (operand_entry_t, heap) **ops,
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unsigned int currindex,
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operand_entry_t curr)
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{
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tree negateop;
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unsigned int i;
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operand_entry_t oe;
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if (opcode != PLUS_EXPR || TREE_CODE (curr->op) != SSA_NAME)
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return false;
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negateop = get_unary_op (curr->op, NEGATE_EXPR);
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if (negateop == NULL_TREE)
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return false;
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/* Any non-negated version will have a rank that is one less than
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the current rank. So once we hit those ranks, if we don't find
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one, we can stop. */
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for (i = currindex + 1;
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VEC_iterate (operand_entry_t, *ops, i, oe)
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&& oe->rank >= curr->rank - 1 ;
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i++)
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{
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if (oe->op == negateop)
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{
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if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
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fprintf (dump_file, "Equivalence: ");
|
|
print_generic_expr (dump_file, negateop, 0);
|
|
fprintf (dump_file, " + -");
|
|
print_generic_expr (dump_file, oe->op, 0);
|
|
fprintf (dump_file, " -> 0\n");
|
|
}
|
|
|
|
VEC_ordered_remove (operand_entry_t, *ops, i);
|
|
add_to_ops_vec (ops, fold_convert(TREE_TYPE (oe->op),
|
|
integer_zero_node));
|
|
VEC_ordered_remove (operand_entry_t, *ops, currindex);
|
|
reassociate_stats.ops_eliminated ++;
|
|
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/* If OPCODE is BIT_IOR_EXPR, BIT_AND_EXPR, and, CURR->OP is really a
|
|
bitwise not expression, look in OPS for a corresponding operand to
|
|
cancel it out. If we find one, remove the other from OPS, replace
|
|
OPS[CURRINDEX] with 0, and return true. Otherwise, return
|
|
false. */
|
|
|
|
static bool
|
|
eliminate_not_pairs (enum tree_code opcode,
|
|
VEC (operand_entry_t, heap) **ops,
|
|
unsigned int currindex,
|
|
operand_entry_t curr)
|
|
{
|
|
tree notop;
|
|
unsigned int i;
|
|
operand_entry_t oe;
|
|
|
|
if ((opcode != BIT_IOR_EXPR && opcode != BIT_AND_EXPR)
|
|
|| TREE_CODE (curr->op) != SSA_NAME)
|
|
return false;
|
|
|
|
notop = get_unary_op (curr->op, BIT_NOT_EXPR);
|
|
if (notop == NULL_TREE)
|
|
return false;
|
|
|
|
/* Any non-not version will have a rank that is one less than
|
|
the current rank. So once we hit those ranks, if we don't find
|
|
one, we can stop. */
|
|
|
|
for (i = currindex + 1;
|
|
VEC_iterate (operand_entry_t, *ops, i, oe)
|
|
&& oe->rank >= curr->rank - 1;
|
|
i++)
|
|
{
|
|
if (oe->op == notop)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Equivalence: ");
|
|
print_generic_expr (dump_file, notop, 0);
|
|
if (opcode == BIT_AND_EXPR)
|
|
fprintf (dump_file, " & ~");
|
|
else if (opcode == BIT_IOR_EXPR)
|
|
fprintf (dump_file, " | ~");
|
|
print_generic_expr (dump_file, oe->op, 0);
|
|
if (opcode == BIT_AND_EXPR)
|
|
fprintf (dump_file, " -> 0\n");
|
|
else if (opcode == BIT_IOR_EXPR)
|
|
fprintf (dump_file, " -> -1\n");
|
|
}
|
|
|
|
if (opcode == BIT_AND_EXPR)
|
|
oe->op = fold_convert (TREE_TYPE (oe->op), integer_zero_node);
|
|
else if (opcode == BIT_IOR_EXPR)
|
|
oe->op = build_low_bits_mask (TREE_TYPE (oe->op),
|
|
TYPE_PRECISION (TREE_TYPE (oe->op)));
|
|
|
|
reassociate_stats.ops_eliminated
|
|
+= VEC_length (operand_entry_t, *ops) - 1;
|
|
VEC_free (operand_entry_t, heap, *ops);
|
|
*ops = NULL;
|
|
VEC_safe_push (operand_entry_t, heap, *ops, oe);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/* Use constant value that may be present in OPS to try to eliminate
|
|
operands. Note that this function is only really used when we've
|
|
eliminated ops for other reasons, or merged constants. Across
|
|
single statements, fold already does all of this, plus more. There
|
|
is little point in duplicating logic, so I've only included the
|
|
identities that I could ever construct testcases to trigger. */
|
|
|
|
static void
|
|
eliminate_using_constants (enum tree_code opcode,
|
|
VEC(operand_entry_t, heap) **ops)
|
|
{
|
|
operand_entry_t oelast = VEC_last (operand_entry_t, *ops);
|
|
|
|
if (oelast->rank == 0 && INTEGRAL_TYPE_P (TREE_TYPE (oelast->op)))
|
|
{
|
|
switch (opcode)
|
|
{
|
|
case BIT_AND_EXPR:
|
|
if (integer_zerop (oelast->op))
|
|
{
|
|
if (VEC_length (operand_entry_t, *ops) != 1)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Found & 0, removing all other ops\n");
|
|
|
|
reassociate_stats.ops_eliminated
|
|
+= VEC_length (operand_entry_t, *ops) - 1;
|
|
|
|
VEC_free (operand_entry_t, heap, *ops);
|
|
*ops = NULL;
|
|
VEC_safe_push (operand_entry_t, heap, *ops, oelast);
|
|
return;
|
|
}
|
|
}
|
|
else if (integer_all_onesp (oelast->op))
|
|
{
|
|
if (VEC_length (operand_entry_t, *ops) != 1)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Found & -1, removing\n");
|
|
VEC_pop (operand_entry_t, *ops);
|
|
reassociate_stats.ops_eliminated++;
|
|
}
|
|
}
|
|
break;
|
|
case BIT_IOR_EXPR:
|
|
if (integer_all_onesp (oelast->op))
|
|
{
|
|
if (VEC_length (operand_entry_t, *ops) != 1)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Found | -1, removing all other ops\n");
|
|
|
|
reassociate_stats.ops_eliminated
|
|
+= VEC_length (operand_entry_t, *ops) - 1;
|
|
|
|
VEC_free (operand_entry_t, heap, *ops);
|
|
*ops = NULL;
|
|
VEC_safe_push (operand_entry_t, heap, *ops, oelast);
|
|
return;
|
|
}
|
|
}
|
|
else if (integer_zerop (oelast->op))
|
|
{
|
|
if (VEC_length (operand_entry_t, *ops) != 1)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Found | 0, removing\n");
|
|
VEC_pop (operand_entry_t, *ops);
|
|
reassociate_stats.ops_eliminated++;
|
|
}
|
|
}
|
|
break;
|
|
case MULT_EXPR:
|
|
if (integer_zerop (oelast->op))
|
|
{
|
|
if (VEC_length (operand_entry_t, *ops) != 1)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Found * 0, removing all other ops\n");
|
|
|
|
reassociate_stats.ops_eliminated
|
|
+= VEC_length (operand_entry_t, *ops) - 1;
|
|
VEC_free (operand_entry_t, heap, *ops);
|
|
*ops = NULL;
|
|
VEC_safe_push (operand_entry_t, heap, *ops, oelast);
|
|
return;
|
|
}
|
|
}
|
|
else if (integer_onep (oelast->op))
|
|
{
|
|
if (VEC_length (operand_entry_t, *ops) != 1)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Found * 1, removing\n");
|
|
VEC_pop (operand_entry_t, *ops);
|
|
reassociate_stats.ops_eliminated++;
|
|
return;
|
|
}
|
|
}
|
|
break;
|
|
case BIT_XOR_EXPR:
|
|
case PLUS_EXPR:
|
|
case MINUS_EXPR:
|
|
if (integer_zerop (oelast->op))
|
|
{
|
|
if (VEC_length (operand_entry_t, *ops) != 1)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Found [|^+] 0, removing\n");
|
|
VEC_pop (operand_entry_t, *ops);
|
|
reassociate_stats.ops_eliminated++;
|
|
return;
|
|
}
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Perform various identities and other optimizations on the list of
|
|
operand entries, stored in OPS. The tree code for the binary
|
|
operation between all the operands is OPCODE. */
|
|
|
|
static void
|
|
optimize_ops_list (enum tree_code opcode,
|
|
VEC (operand_entry_t, heap) **ops)
|
|
{
|
|
unsigned int length = VEC_length (operand_entry_t, *ops);
|
|
unsigned int i;
|
|
operand_entry_t oe;
|
|
operand_entry_t oelast = NULL;
|
|
bool iterate = false;
|
|
|
|
if (length == 1)
|
|
return;
|
|
|
|
oelast = VEC_last (operand_entry_t, *ops);
|
|
|
|
/* If the last two are constants, pop the constants off, merge them
|
|
and try the next two. */
|
|
if (oelast->rank == 0 && is_gimple_min_invariant (oelast->op))
|
|
{
|
|
operand_entry_t oelm1 = VEC_index (operand_entry_t, *ops, length - 2);
|
|
|
|
if (oelm1->rank == 0
|
|
&& is_gimple_min_invariant (oelm1->op)
|
|
&& lang_hooks.types_compatible_p (TREE_TYPE (oelm1->op),
|
|
TREE_TYPE (oelast->op)))
|
|
{
|
|
tree folded = fold_binary (opcode, TREE_TYPE (oelm1->op),
|
|
oelm1->op, oelast->op);
|
|
|
|
if (folded && is_gimple_min_invariant (folded))
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
fprintf (dump_file, "Merging constants\n");
|
|
|
|
VEC_pop (operand_entry_t, *ops);
|
|
VEC_pop (operand_entry_t, *ops);
|
|
|
|
add_to_ops_vec (ops, folded);
|
|
reassociate_stats.constants_eliminated++;
|
|
|
|
optimize_ops_list (opcode, ops);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
eliminate_using_constants (opcode, ops);
|
|
oelast = NULL;
|
|
|
|
for (i = 0; VEC_iterate (operand_entry_t, *ops, i, oe);)
|
|
{
|
|
bool done = false;
|
|
|
|
if (eliminate_not_pairs (opcode, ops, i, oe))
|
|
return;
|
|
if (eliminate_duplicate_pair (opcode, ops, &done, i, oe, oelast)
|
|
|| (!done && eliminate_plus_minus_pair (opcode, ops, i, oe)))
|
|
{
|
|
if (done)
|
|
return;
|
|
iterate = true;
|
|
oelast = NULL;
|
|
continue;
|
|
}
|
|
oelast = oe;
|
|
i++;
|
|
}
|
|
|
|
length = VEC_length (operand_entry_t, *ops);
|
|
oelast = VEC_last (operand_entry_t, *ops);
|
|
|
|
if (iterate)
|
|
optimize_ops_list (opcode, ops);
|
|
}
|
|
|
|
/* Return true if OPERAND is defined by a PHI node which uses the LHS
|
|
of STMT in it's operands. This is also known as a "destructive
|
|
update" operation. */
|
|
|
|
static bool
|
|
is_phi_for_stmt (tree stmt, tree operand)
|
|
{
|
|
tree def_stmt;
|
|
tree lhs = TREE_OPERAND (stmt, 0);
|
|
use_operand_p arg_p;
|
|
ssa_op_iter i;
|
|
|
|
if (TREE_CODE (operand) != SSA_NAME)
|
|
return false;
|
|
|
|
def_stmt = SSA_NAME_DEF_STMT (operand);
|
|
if (TREE_CODE (def_stmt) != PHI_NODE)
|
|
return false;
|
|
|
|
FOR_EACH_PHI_ARG (arg_p, def_stmt, i, SSA_OP_USE)
|
|
if (lhs == USE_FROM_PTR (arg_p))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/* Recursively rewrite our linearized statements so that the operators
|
|
match those in OPS[OPINDEX], putting the computation in rank
|
|
order. */
|
|
|
|
static void
|
|
rewrite_expr_tree (tree stmt, unsigned int opindex,
|
|
VEC(operand_entry_t, heap) * ops)
|
|
{
|
|
tree rhs = TREE_OPERAND (stmt, 1);
|
|
operand_entry_t oe;
|
|
|
|
/* If we have three operands left, then we want to make sure the one
|
|
that gets the double binary op are the ones with the same rank.
|
|
|
|
The alternative we try is to see if this is a destructive
|
|
update style statement, which is like:
|
|
b = phi (a, ...)
|
|
a = c + b;
|
|
In that case, we want to use the destructive update form to
|
|
expose the possible vectorizer sum reduction opportunity.
|
|
In that case, the third operand will be the phi node.
|
|
|
|
We could, of course, try to be better as noted above, and do a
|
|
lot of work to try to find these opportunities in >3 operand
|
|
cases, but it is unlikely to be worth it. */
|
|
if (opindex + 3 == VEC_length (operand_entry_t, ops))
|
|
{
|
|
operand_entry_t oe1, oe2, oe3;
|
|
|
|
oe1 = VEC_index (operand_entry_t, ops, opindex);
|
|
oe2 = VEC_index (operand_entry_t, ops, opindex + 1);
|
|
oe3 = VEC_index (operand_entry_t, ops, opindex + 2);
|
|
|
|
if ((oe1->rank == oe2->rank
|
|
&& oe2->rank != oe3->rank)
|
|
|| (is_phi_for_stmt (stmt, oe3->op)
|
|
&& !is_phi_for_stmt (stmt, oe1->op)
|
|
&& !is_phi_for_stmt (stmt, oe2->op)))
|
|
{
|
|
struct operand_entry temp = *oe3;
|
|
oe3->op = oe1->op;
|
|
oe3->rank = oe1->rank;
|
|
oe1->op = temp.op;
|
|
oe1->rank= temp.rank;
|
|
}
|
|
}
|
|
|
|
/* The final recursion case for this function is that you have
|
|
exactly two operations left.
|
|
If we had one exactly one op in the entire list to start with, we
|
|
would have never called this function, and the tail recursion
|
|
rewrites them one at a time. */
|
|
if (opindex + 2 == VEC_length (operand_entry_t, ops))
|
|
{
|
|
operand_entry_t oe1, oe2;
|
|
|
|
oe1 = VEC_index (operand_entry_t, ops, opindex);
|
|
oe2 = VEC_index (operand_entry_t, ops, opindex + 1);
|
|
|
|
if (TREE_OPERAND (rhs, 0) != oe1->op
|
|
|| TREE_OPERAND (rhs, 1) != oe2->op)
|
|
{
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Transforming ");
|
|
print_generic_expr (dump_file, rhs, 0);
|
|
}
|
|
|
|
TREE_OPERAND (rhs, 0) = oe1->op;
|
|
TREE_OPERAND (rhs, 1) = oe2->op;
|
|
update_stmt (stmt);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, " into ");
|
|
print_generic_stmt (dump_file, rhs, 0);
|
|
}
|
|
|
|
}
|
|
return;
|
|
}
|
|
|
|
/* If we hit here, we should have 3 or more ops left. */
|
|
gcc_assert (opindex + 2 < VEC_length (operand_entry_t, ops));
|
|
|
|
/* Rewrite the next operator. */
|
|
oe = VEC_index (operand_entry_t, ops, opindex);
|
|
|
|
if (oe->op != TREE_OPERAND (rhs, 1))
|
|
{
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Transforming ");
|
|
print_generic_expr (dump_file, rhs, 0);
|
|
}
|
|
|
|
TREE_OPERAND (rhs, 1) = oe->op;
|
|
update_stmt (stmt);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, " into ");
|
|
print_generic_stmt (dump_file, rhs, 0);
|
|
}
|
|
}
|
|
/* Recurse on the LHS of the binary operator, which is guaranteed to
|
|
be the non-leaf side. */
|
|
rewrite_expr_tree (SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0)),
|
|
opindex + 1, ops);
|
|
}
|
|
|
|
/* Transform STMT, which is really (A +B) + (C + D) into the left
|
|
linear form, ((A+B)+C)+D.
|
|
Recurse on D if necessary. */
|
|
|
|
static void
|
|
linearize_expr (tree stmt)
|
|
{
|
|
block_stmt_iterator bsinow, bsirhs;
|
|
tree rhs = TREE_OPERAND (stmt, 1);
|
|
enum tree_code rhscode = TREE_CODE (rhs);
|
|
tree binrhs = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 1));
|
|
tree binlhs = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
|
|
tree newbinrhs = NULL_TREE;
|
|
|
|
gcc_assert (is_reassociable_op (binlhs, TREE_CODE (rhs))
|
|
&& is_reassociable_op (binrhs, TREE_CODE (rhs)));
|
|
|
|
bsinow = bsi_for_stmt (stmt);
|
|
bsirhs = bsi_for_stmt (binrhs);
|
|
bsi_move_before (&bsirhs, &bsinow);
|
|
|
|
TREE_OPERAND (rhs, 1) = TREE_OPERAND (TREE_OPERAND (binrhs, 1), 0);
|
|
if (TREE_CODE (TREE_OPERAND (rhs, 1)) == SSA_NAME)
|
|
newbinrhs = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 1));
|
|
TREE_OPERAND (TREE_OPERAND (binrhs, 1), 0) = TREE_OPERAND (binlhs, 0);
|
|
TREE_OPERAND (rhs, 0) = TREE_OPERAND (binrhs, 0);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Linearized: ");
|
|
print_generic_stmt (dump_file, rhs, 0);
|
|
}
|
|
|
|
reassociate_stats.linearized++;
|
|
update_stmt (binrhs);
|
|
update_stmt (binlhs);
|
|
update_stmt (stmt);
|
|
TREE_VISITED (binrhs) = 1;
|
|
TREE_VISITED (binlhs) = 1;
|
|
TREE_VISITED (stmt) = 1;
|
|
|
|
/* Tail recurse on the new rhs if it still needs reassociation. */
|
|
if (newbinrhs && is_reassociable_op (newbinrhs, rhscode))
|
|
linearize_expr (stmt);
|
|
|
|
}
|
|
|
|
/* If LHS has a single immediate use that is a MODIFY_EXPR, return
|
|
it. Otherwise, return NULL. */
|
|
|
|
static tree
|
|
get_single_immediate_use (tree lhs)
|
|
{
|
|
use_operand_p immuse;
|
|
tree immusestmt;
|
|
|
|
if (TREE_CODE (lhs) == SSA_NAME
|
|
&& single_imm_use (lhs, &immuse, &immusestmt))
|
|
{
|
|
if (TREE_CODE (immusestmt) == RETURN_EXPR)
|
|
immusestmt = TREE_OPERAND (immusestmt, 0);
|
|
if (TREE_CODE (immusestmt) == MODIFY_EXPR)
|
|
return immusestmt;
|
|
}
|
|
return NULL_TREE;
|
|
}
|
|
static VEC(tree, heap) *broken_up_subtracts;
|
|
|
|
|
|
/* Recursively negate the value of TONEGATE, and return the SSA_NAME
|
|
representing the negated value. Insertions of any necessary
|
|
instructions go before BSI.
|
|
This function is recursive in that, if you hand it "a_5" as the
|
|
value to negate, and a_5 is defined by "a_5 = b_3 + b_4", it will
|
|
transform b_3 + b_4 into a_5 = -b_3 + -b_4. */
|
|
|
|
static tree
|
|
negate_value (tree tonegate, block_stmt_iterator *bsi)
|
|
{
|
|
tree negatedef = tonegate;
|
|
tree resultofnegate;
|
|
|
|
if (TREE_CODE (tonegate) == SSA_NAME)
|
|
negatedef = SSA_NAME_DEF_STMT (tonegate);
|
|
|
|
/* If we are trying to negate a name, defined by an add, negate the
|
|
add operands instead. */
|
|
if (TREE_CODE (tonegate) == SSA_NAME
|
|
&& TREE_CODE (negatedef) == MODIFY_EXPR
|
|
&& TREE_CODE (TREE_OPERAND (negatedef, 0)) == SSA_NAME
|
|
&& has_single_use (TREE_OPERAND (negatedef, 0))
|
|
&& TREE_CODE (TREE_OPERAND (negatedef, 1)) == PLUS_EXPR)
|
|
{
|
|
block_stmt_iterator bsi;
|
|
tree binop = TREE_OPERAND (negatedef, 1);
|
|
|
|
bsi = bsi_for_stmt (negatedef);
|
|
TREE_OPERAND (binop, 0) = negate_value (TREE_OPERAND (binop, 0),
|
|
&bsi);
|
|
bsi = bsi_for_stmt (negatedef);
|
|
TREE_OPERAND (binop, 1) = negate_value (TREE_OPERAND (binop, 1),
|
|
&bsi);
|
|
update_stmt (negatedef);
|
|
return TREE_OPERAND (negatedef, 0);
|
|
}
|
|
|
|
tonegate = fold_build1 (NEGATE_EXPR, TREE_TYPE (tonegate), tonegate);
|
|
resultofnegate = force_gimple_operand_bsi (bsi, tonegate, true,
|
|
NULL_TREE);
|
|
VEC_safe_push (tree, heap, broken_up_subtracts, resultofnegate);
|
|
return resultofnegate;
|
|
|
|
}
|
|
|
|
/* Return true if we should break up the subtract in STMT into an add
|
|
with negate. This is true when we the subtract operands are really
|
|
adds, or the subtract itself is used in an add expression. In
|
|
either case, breaking up the subtract into an add with negate
|
|
exposes the adds to reassociation. */
|
|
|
|
static bool
|
|
should_break_up_subtract (tree stmt)
|
|
{
|
|
|
|
tree lhs = TREE_OPERAND (stmt, 0);
|
|
tree rhs = TREE_OPERAND (stmt, 1);
|
|
tree binlhs = TREE_OPERAND (rhs, 0);
|
|
tree binrhs = TREE_OPERAND (rhs, 1);
|
|
tree immusestmt;
|
|
|
|
if (TREE_CODE (binlhs) == SSA_NAME
|
|
&& is_reassociable_op (SSA_NAME_DEF_STMT (binlhs), PLUS_EXPR))
|
|
return true;
|
|
|
|
if (TREE_CODE (binrhs) == SSA_NAME
|
|
&& is_reassociable_op (SSA_NAME_DEF_STMT (binrhs), PLUS_EXPR))
|
|
return true;
|
|
|
|
if (TREE_CODE (lhs) == SSA_NAME
|
|
&& (immusestmt = get_single_immediate_use (lhs))
|
|
&& TREE_CODE (TREE_OPERAND (immusestmt, 1)) == PLUS_EXPR)
|
|
return true;
|
|
return false;
|
|
|
|
}
|
|
|
|
/* Transform STMT from A - B into A + -B. */
|
|
|
|
static void
|
|
break_up_subtract (tree stmt, block_stmt_iterator *bsi)
|
|
{
|
|
tree rhs = TREE_OPERAND (stmt, 1);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Breaking up subtract ");
|
|
print_generic_stmt (dump_file, stmt, 0);
|
|
}
|
|
|
|
TREE_SET_CODE (TREE_OPERAND (stmt, 1), PLUS_EXPR);
|
|
TREE_OPERAND (rhs, 1) = negate_value (TREE_OPERAND (rhs, 1), bsi);
|
|
|
|
update_stmt (stmt);
|
|
}
|
|
|
|
/* Recursively linearize a binary expression that is the RHS of STMT.
|
|
Place the operands of the expression tree in the vector named OPS. */
|
|
|
|
static void
|
|
linearize_expr_tree (VEC(operand_entry_t, heap) **ops, tree stmt)
|
|
{
|
|
block_stmt_iterator bsinow, bsilhs;
|
|
tree rhs = TREE_OPERAND (stmt, 1);
|
|
tree binrhs = TREE_OPERAND (rhs, 1);
|
|
tree binlhs = TREE_OPERAND (rhs, 0);
|
|
tree binlhsdef, binrhsdef;
|
|
bool binlhsisreassoc = false;
|
|
bool binrhsisreassoc = false;
|
|
enum tree_code rhscode = TREE_CODE (rhs);
|
|
|
|
TREE_VISITED (stmt) = 1;
|
|
|
|
if (TREE_CODE (binlhs) == SSA_NAME)
|
|
{
|
|
binlhsdef = SSA_NAME_DEF_STMT (binlhs);
|
|
binlhsisreassoc = is_reassociable_op (binlhsdef, rhscode);
|
|
}
|
|
|
|
if (TREE_CODE (binrhs) == SSA_NAME)
|
|
{
|
|
binrhsdef = SSA_NAME_DEF_STMT (binrhs);
|
|
binrhsisreassoc = is_reassociable_op (binrhsdef, rhscode);
|
|
}
|
|
|
|
/* If the LHS is not reassociable, but the RHS is, we need to swap
|
|
them. If neither is reassociable, there is nothing we can do, so
|
|
just put them in the ops vector. If the LHS is reassociable,
|
|
linearize it. If both are reassociable, then linearize the RHS
|
|
and the LHS. */
|
|
|
|
if (!binlhsisreassoc)
|
|
{
|
|
tree temp;
|
|
|
|
if (!binrhsisreassoc)
|
|
{
|
|
add_to_ops_vec (ops, binrhs);
|
|
add_to_ops_vec (ops, binlhs);
|
|
return;
|
|
}
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "swapping operands of ");
|
|
print_generic_expr (dump_file, stmt, 0);
|
|
}
|
|
|
|
swap_tree_operands (stmt, &TREE_OPERAND (rhs, 0),
|
|
&TREE_OPERAND (rhs, 1));
|
|
update_stmt (stmt);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, " is now ");
|
|
print_generic_stmt (dump_file, stmt, 0);
|
|
}
|
|
|
|
/* We want to make it so the lhs is always the reassociative op,
|
|
so swap. */
|
|
temp = binlhs;
|
|
binlhs = binrhs;
|
|
binrhs = temp;
|
|
}
|
|
else if (binrhsisreassoc)
|
|
{
|
|
linearize_expr (stmt);
|
|
gcc_assert (rhs == TREE_OPERAND (stmt, 1));
|
|
binlhs = TREE_OPERAND (rhs, 0);
|
|
binrhs = TREE_OPERAND (rhs, 1);
|
|
}
|
|
|
|
gcc_assert (TREE_CODE (binrhs) != SSA_NAME
|
|
|| !is_reassociable_op (SSA_NAME_DEF_STMT (binrhs), rhscode));
|
|
bsinow = bsi_for_stmt (stmt);
|
|
bsilhs = bsi_for_stmt (SSA_NAME_DEF_STMT (binlhs));
|
|
bsi_move_before (&bsilhs, &bsinow);
|
|
linearize_expr_tree (ops, SSA_NAME_DEF_STMT (binlhs));
|
|
add_to_ops_vec (ops, binrhs);
|
|
}
|
|
|
|
/* Repropagate the negates back into subtracts, since no other pass
|
|
currently does it. */
|
|
|
|
static void
|
|
repropagate_negates (void)
|
|
{
|
|
unsigned int i = 0;
|
|
tree negate;
|
|
|
|
for (i = 0; VEC_iterate (tree, broken_up_subtracts, i, negate); i++)
|
|
{
|
|
tree user = get_single_immediate_use (negate);
|
|
|
|
/* The negate operand can be either operand of a PLUS_EXPR
|
|
(it can be the LHS if the RHS is a constant for example).
|
|
|
|
Force the negate operand to the RHS of the PLUS_EXPR, then
|
|
transform the PLUS_EXPR into a MINUS_EXPR. */
|
|
if (user
|
|
&& TREE_CODE (user) == MODIFY_EXPR
|
|
&& TREE_CODE (TREE_OPERAND (user, 1)) == PLUS_EXPR)
|
|
{
|
|
tree rhs = TREE_OPERAND (user, 1);
|
|
|
|
/* If the negated operand appears on the LHS of the
|
|
PLUS_EXPR, exchange the operands of the PLUS_EXPR
|
|
to force the negated operand to the RHS of the PLUS_EXPR. */
|
|
if (TREE_OPERAND (TREE_OPERAND (user, 1), 0) == negate)
|
|
{
|
|
tree temp = TREE_OPERAND (rhs, 0);
|
|
TREE_OPERAND (rhs, 0) = TREE_OPERAND (rhs, 1);
|
|
TREE_OPERAND (rhs, 1) = temp;
|
|
}
|
|
|
|
/* Now transform the PLUS_EXPR into a MINUS_EXPR and replace
|
|
the RHS of the PLUS_EXPR with the operand of the NEGATE_EXPR. */
|
|
if (TREE_OPERAND (TREE_OPERAND (user, 1), 1) == negate)
|
|
{
|
|
TREE_SET_CODE (rhs, MINUS_EXPR);
|
|
TREE_OPERAND (rhs, 1) = get_unary_op (negate, NEGATE_EXPR);
|
|
update_stmt (user);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Break up subtract operations in block BB.
|
|
|
|
We do this top down because we don't know whether the subtract is
|
|
part of a possible chain of reassociation except at the top.
|
|
|
|
IE given
|
|
d = f + g
|
|
c = a + e
|
|
b = c - d
|
|
q = b - r
|
|
k = t - q
|
|
|
|
we want to break up k = t - q, but we won't until we've transformed q
|
|
= b - r, which won't be broken up until we transform b = c - d. */
|
|
|
|
static void
|
|
break_up_subtract_bb (basic_block bb)
|
|
{
|
|
block_stmt_iterator bsi;
|
|
basic_block son;
|
|
|
|
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
|
|
{
|
|
tree stmt = bsi_stmt (bsi);
|
|
|
|
if (TREE_CODE (stmt) == MODIFY_EXPR)
|
|
{
|
|
tree lhs = TREE_OPERAND (stmt, 0);
|
|
tree rhs = TREE_OPERAND (stmt, 1);
|
|
|
|
TREE_VISITED (stmt) = 0;
|
|
/* If unsafe math optimizations we can do reassociation for
|
|
non-integral types. */
|
|
if ((!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
|
|
|| !INTEGRAL_TYPE_P (TREE_TYPE (rhs)))
|
|
&& (!SCALAR_FLOAT_TYPE_P (TREE_TYPE (rhs))
|
|
|| !SCALAR_FLOAT_TYPE_P (TREE_TYPE(lhs))
|
|
|| !flag_unsafe_math_optimizations))
|
|
continue;
|
|
|
|
/* Check for a subtract used only in an addition. If this
|
|
is the case, transform it into add of a negate for better
|
|
reassociation. IE transform C = A-B into C = A + -B if C
|
|
is only used in an addition. */
|
|
if (TREE_CODE (rhs) == MINUS_EXPR)
|
|
if (should_break_up_subtract (stmt))
|
|
break_up_subtract (stmt, &bsi);
|
|
}
|
|
}
|
|
for (son = first_dom_son (CDI_DOMINATORS, bb);
|
|
son;
|
|
son = next_dom_son (CDI_DOMINATORS, son))
|
|
break_up_subtract_bb (son);
|
|
}
|
|
|
|
/* Reassociate expressions in basic block BB and its post-dominator as
|
|
children. */
|
|
|
|
static void
|
|
reassociate_bb (basic_block bb)
|
|
{
|
|
block_stmt_iterator bsi;
|
|
basic_block son;
|
|
|
|
for (bsi = bsi_last (bb); !bsi_end_p (bsi); bsi_prev (&bsi))
|
|
{
|
|
tree stmt = bsi_stmt (bsi);
|
|
|
|
if (TREE_CODE (stmt) == MODIFY_EXPR)
|
|
{
|
|
tree lhs = TREE_OPERAND (stmt, 0);
|
|
tree rhs = TREE_OPERAND (stmt, 1);
|
|
|
|
/* If this was part of an already processed tree, we don't
|
|
need to touch it again. */
|
|
if (TREE_VISITED (stmt))
|
|
continue;
|
|
|
|
/* If unsafe math optimizations we can do reassociation for
|
|
non-integral types. */
|
|
if ((!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
|
|
|| !INTEGRAL_TYPE_P (TREE_TYPE (rhs)))
|
|
&& (!SCALAR_FLOAT_TYPE_P (TREE_TYPE (rhs))
|
|
|| !SCALAR_FLOAT_TYPE_P (TREE_TYPE(lhs))
|
|
|| !flag_unsafe_math_optimizations))
|
|
continue;
|
|
|
|
if (associative_tree_code (TREE_CODE (rhs)))
|
|
{
|
|
VEC(operand_entry_t, heap) *ops = NULL;
|
|
|
|
/* There may be no immediate uses left by the time we
|
|
get here because we may have eliminated them all. */
|
|
if (TREE_CODE (lhs) == SSA_NAME && has_zero_uses (lhs))
|
|
continue;
|
|
|
|
TREE_VISITED (stmt) = 1;
|
|
linearize_expr_tree (&ops, stmt);
|
|
qsort (VEC_address (operand_entry_t, ops),
|
|
VEC_length (operand_entry_t, ops),
|
|
sizeof (operand_entry_t),
|
|
sort_by_operand_rank);
|
|
optimize_ops_list (TREE_CODE (rhs), &ops);
|
|
|
|
if (VEC_length (operand_entry_t, ops) == 1)
|
|
{
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, "Transforming ");
|
|
print_generic_expr (dump_file, rhs, 0);
|
|
}
|
|
TREE_OPERAND (stmt, 1) = VEC_last (operand_entry_t, ops)->op;
|
|
update_stmt (stmt);
|
|
|
|
if (dump_file && (dump_flags & TDF_DETAILS))
|
|
{
|
|
fprintf (dump_file, " into ");
|
|
print_generic_stmt (dump_file,
|
|
TREE_OPERAND (stmt, 1), 0);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
rewrite_expr_tree (stmt, 0, ops);
|
|
}
|
|
|
|
VEC_free (operand_entry_t, heap, ops);
|
|
}
|
|
}
|
|
}
|
|
for (son = first_dom_son (CDI_POST_DOMINATORS, bb);
|
|
son;
|
|
son = next_dom_son (CDI_POST_DOMINATORS, son))
|
|
reassociate_bb (son);
|
|
}
|
|
|
|
void dump_ops_vector (FILE *file, VEC (operand_entry_t, heap) *ops);
|
|
void debug_ops_vector (VEC (operand_entry_t, heap) *ops);
|
|
|
|
/* Dump the operand entry vector OPS to FILE. */
|
|
|
|
void
|
|
dump_ops_vector (FILE *file, VEC (operand_entry_t, heap) *ops)
|
|
{
|
|
operand_entry_t oe;
|
|
unsigned int i;
|
|
|
|
for (i = 0; VEC_iterate (operand_entry_t, ops, i, oe); i++)
|
|
{
|
|
fprintf (file, "Op %d -> rank: %d, tree: ", i, oe->rank);
|
|
print_generic_stmt (file, oe->op, 0);
|
|
}
|
|
}
|
|
|
|
/* Dump the operand entry vector OPS to STDERR. */
|
|
|
|
void
|
|
debug_ops_vector (VEC (operand_entry_t, heap) *ops)
|
|
{
|
|
dump_ops_vector (stderr, ops);
|
|
}
|
|
|
|
static void
|
|
do_reassoc (void)
|
|
{
|
|
break_up_subtract_bb (ENTRY_BLOCK_PTR);
|
|
reassociate_bb (EXIT_BLOCK_PTR);
|
|
}
|
|
|
|
/* Initialize the reassociation pass. */
|
|
|
|
static void
|
|
init_reassoc (void)
|
|
{
|
|
int i;
|
|
unsigned int rank = 2;
|
|
tree param;
|
|
int *bbs = XNEWVEC (int, last_basic_block + 1);
|
|
|
|
memset (&reassociate_stats, 0, sizeof (reassociate_stats));
|
|
|
|
operand_entry_pool = create_alloc_pool ("operand entry pool",
|
|
sizeof (struct operand_entry), 30);
|
|
|
|
/* Reverse RPO (Reverse Post Order) will give us something where
|
|
deeper loops come later. */
|
|
pre_and_rev_post_order_compute (NULL, bbs, false);
|
|
bb_rank = XCNEWVEC (unsigned int, last_basic_block + 1);
|
|
|
|
operand_rank = htab_create (511, operand_entry_hash,
|
|
operand_entry_eq, 0);
|
|
|
|
/* Give each argument a distinct rank. */
|
|
for (param = DECL_ARGUMENTS (current_function_decl);
|
|
param;
|
|
param = TREE_CHAIN (param))
|
|
{
|
|
if (default_def (param) != NULL)
|
|
{
|
|
tree def = default_def (param);
|
|
insert_operand_rank (def, ++rank);
|
|
}
|
|
}
|
|
|
|
/* Give the chain decl a distinct rank. */
|
|
if (cfun->static_chain_decl != NULL)
|
|
{
|
|
tree def = default_def (cfun->static_chain_decl);
|
|
if (def != NULL)
|
|
insert_operand_rank (def, ++rank);
|
|
}
|
|
|
|
/* Set up rank for each BB */
|
|
for (i = 0; i < n_basic_blocks - NUM_FIXED_BLOCKS; i++)
|
|
bb_rank[bbs[i]] = ++rank << 16;
|
|
|
|
free (bbs);
|
|
calculate_dominance_info (CDI_DOMINATORS);
|
|
calculate_dominance_info (CDI_POST_DOMINATORS);
|
|
broken_up_subtracts = NULL;
|
|
}
|
|
|
|
/* Cleanup after the reassociation pass, and print stats if
|
|
requested. */
|
|
|
|
static void
|
|
fini_reassoc (void)
|
|
{
|
|
|
|
if (dump_file && (dump_flags & TDF_STATS))
|
|
{
|
|
fprintf (dump_file, "Reassociation stats:\n");
|
|
fprintf (dump_file, "Linearized: %d\n",
|
|
reassociate_stats.linearized);
|
|
fprintf (dump_file, "Constants eliminated: %d\n",
|
|
reassociate_stats.constants_eliminated);
|
|
fprintf (dump_file, "Ops eliminated: %d\n",
|
|
reassociate_stats.ops_eliminated);
|
|
fprintf (dump_file, "Statements rewritten: %d\n",
|
|
reassociate_stats.rewritten);
|
|
}
|
|
htab_delete (operand_rank);
|
|
|
|
free_alloc_pool (operand_entry_pool);
|
|
free (bb_rank);
|
|
VEC_free (tree, heap, broken_up_subtracts);
|
|
free_dominance_info (CDI_POST_DOMINATORS);
|
|
}
|
|
|
|
/* Gate and execute functions for Reassociation. */
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|
|
|
static unsigned int
|
|
execute_reassoc (void)
|
|
{
|
|
init_reassoc ();
|
|
|
|
do_reassoc ();
|
|
repropagate_negates ();
|
|
|
|
fini_reassoc ();
|
|
return 0;
|
|
}
|
|
|
|
struct tree_opt_pass pass_reassoc =
|
|
{
|
|
"reassoc", /* name */
|
|
NULL, /* gate */
|
|
execute_reassoc, /* execute */
|
|
NULL, /* sub */
|
|
NULL, /* next */
|
|
0, /* static_pass_number */
|
|
TV_TREE_REASSOC, /* tv_id */
|
|
PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
|
|
0, /* properties_provided */
|
|
0, /* properties_destroyed */
|
|
0, /* todo_flags_start */
|
|
TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */
|
|
0 /* letter */
|
|
};
|