re PR tree-optimization/57742 (memset(malloc(n),0,n) -> calloc(n,1))

2014-06-25  Marc Glisse  <marc.glisse@inria.fr>

	PR tree-optimization/57742
gcc/
	* tree-ssa-strlen.c (handle_builtin_memset): Update strinfo
	after replacing the statement.
gcc/testsuite/
	* gcc.dg/tree-ssa/calloc-3.c: New file.

From-SVN: r211977

gcc/ChangeLog

+2014-06-25  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR tree-optimization/57742
+	* tree-ssa-strlen.c (handle_builtin_memset): Update strinfo
+	after replacing the statement.
+
 2014-06-25  Nick Clifton  <nickc@redhat.com>
 
 	* config/v850/v850.c (GHS_default_section_names): Change to const

gcc/testsuite/ChangeLog

+2014-06-25  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR tree-optimization/57742
+	* gcc.dg/tree-ssa/calloc-3.c: New file.
+
 2014-06-25  Richard Biener  <rguenther@suse.de>
 
 	PR testsuite/61560

gcc/testsuite/gcc.dg/tree-ssa/calloc-3.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+void*f(){
+    char*p=__builtin_malloc(42);
+    __builtin_memset(p,0,42);
+    __builtin_memset(p,0,42);
+    return p;
+};
+
+/* { dg-final { scan-tree-dump-not "malloc" "optimized" } } */
+/* { dg-final { scan-tree-dump-times "calloc" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-not "memset" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/tree-ssa-strlen.c

@@ -1653,6 +1653,8 @@ handle_builtin_memset (gimple_stmt_iterator *gsi)
       gimple_stmt_iterator gsi1 = gsi_for_stmt (stmt1);
       update_gimple_call (&gsi1, builtin_decl_implicit (BUILT_IN_CALLOC), 2,
 			  size, build_one_cst (size_type_node));
+      si1->length = build_int_cst (size_type_node, 0);
+      si1->stmt = gsi_stmt (gsi1);
     }
   else
     return true;