re PR middle-end/52691 (va_start to builtin_next_arg optimization lost)

	PR middle-end/52691
	* tree-ssa-ccp.c (optimize_stdarg_builtin): Optimize
	__builtin_va_start to __builtin_next_arg if the latter is
	builtin_decl_explicit_p rather than when it is not.

	* gcc.dg/pr52691.c: New test.

From-SVN: r185917

gcc/ChangeLog

 2012-03-28  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/52691
+	* tree-ssa-ccp.c (optimize_stdarg_builtin): Optimize
+	__builtin_va_start to __builtin_next_arg if the latter is
+	builtin_decl_explicit_p rather than when it is not.
+
 	PR middle-end/52750
 	* tree-vect-generic.c (vector_element): Perform multiplication
 	for pos in bitsizetype type instead of idx type.

gcc/testsuite/ChangeLog

 2012-03-28  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/52691
+	* gcc.dg/pr52691.c: New test.
+
 	PR middle-end/52750
 	* gcc.c-torture/compile/pr52750.c: New test.
 

gcc/testsuite/gcc.dg/pr52691.c

+/* PR middle-end/52691 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#include <stdarg.h>
+
+int
+foo (int a, ...)
+{
+  int b = 0, c = 0;
+  va_list ap;
+  va_start (ap, a);
+  if (a > 1)
+    b = va_arg (ap, double);
+  if (a > 2)
+    c = va_arg (ap, long long);
+  va_end (ap);
+  return a + b + c;
+}
+
+/* { dg-final { scan-tree-dump "__builtin_next_arg" "optimized" { target { { i?86-*-* x86_64-*-* } && ia32 } } } } */
+/* { dg-final { scan-tree-dump "__builtin_next_arg" "optimized" { target { powerpc*-*-darwin* powerpc*-*-aix* } } } } */
+/* { dg-final { scan-tree-dump "__builtin_next_arg" "optimized" { target { powerpc*-*-linux* && lp64 } } } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/tree-ssa-ccp.c

@@ -2288,7 +2288,7 @@ optimize_stdarg_builtin (gimple call)
     case BUILT_IN_VA_START:
       if (!va_list_simple_ptr
 	  || targetm.expand_builtin_va_start != NULL
-          || builtin_decl_explicit_p (BUILT_IN_NEXT_ARG))
+	  || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG))
 	return NULL_TREE;
 
       if (gimple_call_num_args (call) != 2)