re PR c++/23372 (Temporary aggregate copy not elided when passing parameters by value)

2006-01-30  Richard Guenther  <rguenther@suse.de>

	PR c++/23372
	* gimplify.c (gimplify_target_expr): Handle easy cases
	without creating a temporary.

	* gcc.dg/pr23372-1.C: New testcase.

From-SVN: r110396

gcc/ChangeLog

+2006-01-30  Richard Guenther  <rguenther@suse.de>
+
+	PR c++/23372
+	* gimplify.c (gimplify_target_expr): Handle easy cases
+	without creating a temporary.
+
 2006-01-30  Nathan Sidwell  <nathan@codesourcery.com>
 
 	* vec.h (safe_grow): Remove duplicated line.

gcc/gimplify.c

@@ -4053,6 +4053,15 @@ gimplify_target_expr (tree *expr_p, tree *pre_p, tree *post_p)
 
   if (init)
     {
+      /* Try to avoid the temporary if possible.  */
+      if (TREE_CODE (init) == INDIRECT_REF
+	  && !TREE_SIDE_EFFECTS (init)
+          && !TARGET_EXPR_CLEANUP (targ))
+        {
+          *expr_p = init;
+          return GS_OK;
+        }
+
       /* TARGET_EXPR temps aren't part of the enclosing block, so add it
 	 to the temps list.  */
       gimple_add_tmp_var (temp);

gcc/testsuite/ChangeLog

+2006-01-30  Richard Guenther  <rguenther@suse.de>
+
+	PR c++/23372
+	* gcc.dg/pr23372-1.C: New testcase.
+
 2006-01-29  Diego Novillo  <dnovillo@redhat.com>
 
 	* gcc.dg/gomp/pr25874.c: New test.

gcc/testsuite/gcc.dg/pr23372-1.c

+/* { dg-do compile } */
+/* { dg-options "-Os" } */
+
+struct A {
+  int a[1000];
+};
+void f(struct A);
+void g(struct A *a) { f(*a); }
+
+/* { dg-final { scan-assembler-times "memcpy" 1 } } */