[PATCH] Put C DECL_EXPRs into OMP_FOR_PRE_BODY (PR c/67502)

[Jakub Jelinek]

Hi!

This C FE patch tweaks c_parser_omp_for_loop so that it puts
for IVs declared in for loops their DECL_EXPRs into OMP_FOR_PRE_BODY
so that the gimplifier can find them and avoid doing copyout for them.

Bootstrapped/regtested on x86_64-linux and i686-linux, committed to trunk
and 5 branch.

2015-09-10  Jakub Jelinek  <ja...@redhat.com>

        PR c/67502
        * c-parser.c (c_parser_omp_for_loop): Emit DECL_EXPR stmts
        into OMP_FOR_PRE_BODY rather than before the loop.

        * c-c++-common/gomp/pr67502.c: New test.

--- gcc/c/c-parser.c.jj 2015-09-09 09:24:11.000000000 +0200
+++ gcc/c/c-parser.c    2015-09-09 11:00:30.119045568 +0200
@@ -12869,7 +12869,8 @@ c_parser_omp_for_loop (location_t loc, c
                       tree clauses, tree *cclauses)
 {
   tree decl, cond, incr, save_break, save_cont, body, init, stmt, cl;
-  tree declv, condv, incrv, initv, ret = NULL;
+  tree declv, condv, incrv, initv, ret = NULL_TREE;
+  tree pre_body = NULL_TREE, this_pre_body;
   bool fail = false, open_brace_parsed = false;
   int i, collapse = 1, nbraces = 0;
   location_t for_loc;
@@ -12913,8 +12914,23 @@ c_parser_omp_for_loop (location_t loc, c
        {
          if (i > 0)
            vec_safe_push (for_block, c_begin_compound_stmt (true));
+         this_pre_body = push_stmt_list ();
          c_parser_declaration_or_fndef (parser, true, true, true, true, true,
                                         NULL, vNULL);
+         if (this_pre_body)
+           {
+             this_pre_body = pop_stmt_list (this_pre_body);
+             if (pre_body)
+               {
+                 tree t = pre_body;   
+                 pre_body = push_stmt_list ();
+                 add_stmt (t);
+                 add_stmt (this_pre_body);
+                 pre_body = pop_stmt_list (pre_body);
+               }
+             else
+               pre_body = this_pre_body;
+           }
          decl = check_for_loop_decls (for_loc, flag_isoc99);
          if (decl == NULL)
            goto error_init;
@@ -13109,7 +13125,7 @@ c_parser_omp_for_loop (location_t loc, c
   if (!fail)
     {
       stmt = c_finish_omp_for (loc, code, declv, initv, condv,
-                              incrv, body, NULL);
+                              incrv, body, pre_body);
       if (stmt)
        {
          if (cclauses != NULL
--- gcc/testsuite/c-c++-common/gomp/pr67502.c.jj        2015-09-09 
11:06:33.471688920 +0200
+++ gcc/testsuite/c-c++-common/gomp/pr67502.c   2015-09-09 11:07:13.341101057 
+0200
@@ -0,0 +1,16 @@
+/* PR c/67502 */
+/* { dg-do compile } */
+/* { dg-options "-fopenmp" } */
+/* { dg-additional-options "-std=c99" { target c } } */
+
+void bar (int, int);
+
+void
+foo (void)
+{
+#pragma omp parallel
+#pragma omp for simd collapse(2)
+  for (int i = 0; i < 16; ++i)
+    for (int j = 0; j < 16; ++j)
+      bar (i, j);
+}

        Jakub