227 lines
6.9 KiB
C
227 lines
6.9 KiB
C
/* Tree lowering pass. This pass gimplifies the tree representation built
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by the C-based front ends. The structure of gimplified, or
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language-independent, trees is dictated by the grammar described in this
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file.
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Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
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Lowering of expressions contributed by Sebastian Pop <s.pop@laposte.net>
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Re-written to support lowering of whole function trees, documentation
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and miscellaneous cleanups by Diego Novillo <dnovillo@redhat.com>
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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 it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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 the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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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 "tree.h"
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#include "varray.h"
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#include "c-tree.h"
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#include "c-common.h"
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#include "tree-gimple.h"
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#include "hard-reg-set.h"
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#include "basic-block.h"
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#include "tree-flow.h"
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#include "tree-inline.h"
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#include "diagnostic.h"
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#include "langhooks.h"
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#include "langhooks-def.h"
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#include "flags.h"
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#include "rtl.h"
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#include "toplev.h"
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#include "tree-dump.h"
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#include "c-pretty-print.h"
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#include "cgraph.h"
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/* The gimplification pass converts the language-dependent trees
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(ld-trees) emitted by the parser into language-independent trees
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(li-trees) that are the target of SSA analysis and transformations.
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Language-independent trees are based on the SIMPLE intermediate
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representation used in the McCAT compiler framework:
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"Designing the McCAT Compiler Based on a Family of Structured
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Intermediate Representations,"
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L. Hendren, C. Donawa, M. Emami, G. Gao, Justiani, and B. Sridharan,
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Proceedings of the 5th International Workshop on Languages and
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Compilers for Parallel Computing, no. 757 in Lecture Notes in
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Computer Science, New Haven, Connecticut, pp. 406-420,
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Springer-Verlag, August 3-5, 1992.
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http://www-acaps.cs.mcgill.ca/info/McCAT/McCAT.html
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Basically, we walk down gimplifying the nodes that we encounter. As we
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walk back up, we check that they fit our constraints, and copy them
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into temporaries if not. */
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/* Gimplification of statement trees. */
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/* Convert the tree representation of FNDECL from C frontend trees to
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GENERIC. */
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void
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c_genericize (tree fndecl)
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{
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FILE *dump_orig;
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int local_dump_flags;
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struct cgraph_node *cgn;
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/* Dump the C-specific tree IR. */
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dump_orig = dump_begin (TDI_original, &local_dump_flags);
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if (dump_orig)
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{
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fprintf (dump_orig, "\n;; Function %s",
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lang_hooks.decl_printable_name (fndecl, 2));
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fprintf (dump_orig, " (%s)\n",
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IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (fndecl)));
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fprintf (dump_orig, ";; enabled by -%s\n", dump_flag_name (TDI_original));
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fprintf (dump_orig, "\n");
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if (local_dump_flags & TDF_RAW)
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dump_node (DECL_SAVED_TREE (fndecl),
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TDF_SLIM | local_dump_flags, dump_orig);
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else
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print_c_tree (dump_orig, DECL_SAVED_TREE (fndecl));
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fprintf (dump_orig, "\n");
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dump_end (TDI_original, dump_orig);
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}
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/* Go ahead and gimplify for now. */
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gimplify_function_tree (fndecl);
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/* Dump the genericized tree IR. */
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dump_function (TDI_generic, fndecl);
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/* Genericize all nested functions now. We do things in this order so
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that items like VLA sizes are expanded properly in the context of
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the correct function. */
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cgn = cgraph_node (fndecl);
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for (cgn = cgn->nested; cgn ; cgn = cgn->next_nested)
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c_genericize (cgn->decl);
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}
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static void
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add_block_to_enclosing (tree block)
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{
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tree enclosing;
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for (enclosing = gimple_current_bind_expr ();
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enclosing; enclosing = TREE_CHAIN (enclosing))
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if (BIND_EXPR_BLOCK (enclosing))
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break;
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enclosing = BIND_EXPR_BLOCK (enclosing);
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BLOCK_SUBBLOCKS (enclosing) = chainon (BLOCK_SUBBLOCKS (enclosing), block);
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}
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/* Genericize a scope by creating a new BIND_EXPR.
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BLOCK is either a BLOCK representing the scope or a chain of _DECLs.
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In the latter case, we need to create a new BLOCK and add it to the
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BLOCK_SUBBLOCKS of the enclosing block.
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BODY is a chain of C _STMT nodes for the contents of the scope, to be
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genericized. */
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tree
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c_build_bind_expr (tree block, tree body)
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{
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tree decls, bind;
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if (block == NULL_TREE)
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decls = NULL_TREE;
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else if (TREE_CODE (block) == BLOCK)
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decls = BLOCK_VARS (block);
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else
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{
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decls = block;
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if (DECL_ARTIFICIAL (decls))
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block = NULL_TREE;
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else
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{
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block = make_node (BLOCK);
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BLOCK_VARS (block) = decls;
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add_block_to_enclosing (block);
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}
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}
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if (!body)
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body = build_empty_stmt ();
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if (decls || block)
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{
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bind = build3 (BIND_EXPR, void_type_node, decls, body, block);
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TREE_SIDE_EFFECTS (bind) = 1;
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}
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else
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bind = body;
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return bind;
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}
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/* Gimplification of expression trees. */
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/* Gimplify a C99 compound literal expression. This just means adding
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the DECL_EXPR before the current statement and using its anonymous
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decl instead. */
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static enum gimplify_status
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gimplify_compound_literal_expr (tree *expr_p, tree *pre_p)
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{
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tree decl_s = COMPOUND_LITERAL_EXPR_DECL_STMT (*expr_p);
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tree decl = DECL_EXPR_DECL (decl_s);
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/* This decl isn't mentioned in the enclosing block, so add it to the
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list of temps. FIXME it seems a bit of a kludge to say that
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anonymous artificial vars aren't pushed, but everything else is. */
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if (DECL_NAME (decl) == NULL_TREE && !DECL_SEEN_IN_BIND_EXPR_P (decl))
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gimple_add_tmp_var (decl);
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gimplify_and_add (decl_s, pre_p);
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*expr_p = decl;
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return GS_OK;
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}
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/* Do C-specific gimplification. Args are as for gimplify_expr. */
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int
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c_gimplify_expr (tree *expr_p, tree *pre_p, tree *post_p ATTRIBUTE_UNUSED)
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{
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enum tree_code code = TREE_CODE (*expr_p);
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switch (code)
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{
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case DECL_EXPR:
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/* This is handled mostly by gimplify.c, but we have to deal with
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not warning about int x = x; as it is a GCC extension to turn off
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this warning but only if warn_init_self is zero. */
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if (TREE_CODE (DECL_EXPR_DECL (*expr_p)) == VAR_DECL
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&& !DECL_EXTERNAL (DECL_EXPR_DECL (*expr_p))
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&& !TREE_STATIC (DECL_EXPR_DECL (*expr_p))
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&& (DECL_INITIAL (DECL_EXPR_DECL (*expr_p))
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== DECL_EXPR_DECL (*expr_p))
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&& !warn_init_self)
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TREE_NO_WARNING (DECL_EXPR_DECL (*expr_p)) = 1;
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return GS_UNHANDLED;
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case COMPOUND_LITERAL_EXPR:
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return gimplify_compound_literal_expr (expr_p, pre_p);
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default:
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return GS_UNHANDLED;
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}
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}
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