re PR c/19449 (__builtin_constant_p cannot resolve to const when optimizing)

	PR c/19449
	* tree.h (force_folding_builtin_constant_p): New decl.
	* builtins.c (force_folding_builtin_constant_p): New variable.
	(fold_builtin_constant_p): Fold immediately also if
	force_folding_builtin_constant_p.

	* c-parser.c (c_parser_get_builtin_args): Add choose_expr_p
	argument.  If set, or it temporarily for parsing of the first
	argument into force_folding_builtin_constant_p.
	(c_parser_postfix_expression): Adjust callers.

	* gcc.c-torture/execute/pr19449.c: New test.

From-SVN: r197393

gcc/ChangeLog

+2013-04-03  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/19449
+	* tree.h (force_folding_builtin_constant_p): New decl.
+	* builtins.c (force_folding_builtin_constant_p): New variable.
+	(fold_builtin_constant_p): Fold immediately also if
+	force_folding_builtin_constant_p.
+
 2013-04-03  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/56812

gcc/builtins.c

@@ -75,6 +75,9 @@ const char * built_in_names[(int) END_BUILTINS] =
    initialized to NULL_TREE.  */
 builtin_info_type builtin_info;
 
+/* Non-zero if __builtin_constant_p should be folded right away.  */
+bool force_folding_builtin_constant_p;
+
 static const char *c_getstr (tree);
 static rtx c_readstr (const char *, enum machine_mode);
 static int target_char_cast (tree, char *);
@@ -6974,7 +6977,8 @@ fold_builtin_constant_p (tree arg)
       || AGGREGATE_TYPE_P (TREE_TYPE (arg))
       || POINTER_TYPE_P (TREE_TYPE (arg))
       || cfun == 0
-      || folding_initializer)
+      || folding_initializer
+      || force_folding_builtin_constant_p)
     return integer_zero_node;
 
   return NULL_TREE;

gcc/c/ChangeLog

+2013-04-03  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/19449
+	* c-parser.c (c_parser_get_builtin_args): Add choose_expr_p
+	argument.  If set, or it temporarily for parsing of the first
+	argument into force_folding_builtin_constant_p.
+	(c_parser_postfix_expression): Adjust callers.
+
 2013-03-21  Richard Biener  <rguenther@suse.de>
 
 	* c-objc-common.c (c_tree_printer): Use DECL_HAS_DEBUG_EXPR_P

gcc/c/c-parser.c

@@ -6114,11 +6114,13 @@ c_parser_alignof_expression (c_parser *parser)
    stores the arguments in CEXPR_LIST.  */
 static bool
 c_parser_get_builtin_args (c_parser *parser, const char *bname,
-			   vec<c_expr_t, va_gc> **ret_cexpr_list)
+			   vec<c_expr_t, va_gc> **ret_cexpr_list,
+			   bool choose_expr_p)
 {
   location_t loc = c_parser_peek_token (parser)->location;
   vec<c_expr_t, va_gc> *cexpr_list;
   c_expr_t expr;
+  bool saved_force_folding_builtin_constant_p;
 
   *ret_cexpr_list = NULL;
   if (c_parser_next_token_is_not (parser, CPP_OPEN_PAREN))
@@ -6135,7 +6137,12 @@ c_parser_get_builtin_args (c_parser *parser, const char *bname,
       return true;
     }
 
+  saved_force_folding_builtin_constant_p
+    = force_folding_builtin_constant_p;
+  force_folding_builtin_constant_p |= choose_expr_p;
   expr = c_parser_expr_no_commas (parser, NULL);
+  force_folding_builtin_constant_p
+    = saved_force_folding_builtin_constant_p;
   vec_alloc (cexpr_list, 1);
   C_EXPR_APPEND (cexpr_list, expr);
   while (c_parser_next_token_is (parser, CPP_COMMA))
@@ -6509,7 +6516,7 @@ c_parser_postfix_expression (c_parser *parser)
 	    c_parser_consume_token (parser);
 	    if (!c_parser_get_builtin_args (parser,
 					    "__builtin_choose_expr",
-					    &cexpr_list))
+					    &cexpr_list, true))
 	      {
 		expr.value = error_mark_node;
 		break;
@@ -6591,7 +6598,7 @@ c_parser_postfix_expression (c_parser *parser)
 	    c_parser_consume_token (parser);
 	    if (!c_parser_get_builtin_args (parser,
 					    "__builtin_complex",
-					    &cexpr_list))
+					    &cexpr_list, false))
 	      {
 		expr.value = error_mark_node;
 		break;
@@ -6653,7 +6660,7 @@ c_parser_postfix_expression (c_parser *parser)
 	    c_parser_consume_token (parser);
 	    if (!c_parser_get_builtin_args (parser,
 					    "__builtin_shuffle",
-					    &cexpr_list))
+					    &cexpr_list, false))
 	      {
 		expr.value = error_mark_node;
 		break;

gcc/testsuite/ChangeLog

+2013-04-03  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/19449
+	* gcc.c-torture/execute/pr19449.c: New test.
+
 2013-04-03  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/56812

gcc/testsuite/gcc.c-torture/execute/pr19449.c

+/* PR c/19449 */
+
+extern void abort (void);
+
+int y;
+int z = __builtin_choose_expr (!__builtin_constant_p (y), 3, 4);
+
+int
+foo (int x)
+{
+  return __builtin_choose_expr (!__builtin_constant_p (x), 3, y++);
+}
+
+int
+main ()
+{
+  if (y || z != 3 || foo (4) != 3)
+    abort ();
+  return 0;
+}

gcc/tree.h

@@ -5855,6 +5855,10 @@ fold_build_pointer_plus_hwi_loc (location_t loc, tree ptr, HOST_WIDE_INT off)
 	fold_build_pointer_plus_hwi_loc (UNKNOWN_LOCATION, p, o)
 
 /* In builtins.c */
+
+/* Non-zero if __builtin_constant_p should be folded right away.  */
+extern bool force_folding_builtin_constant_p;
+
 extern bool avoid_folding_inline_builtin (tree);
 extern tree fold_call_expr (location_t, tree, bool);
 extern tree fold_builtin_fputs (location_t, tree, tree, bool, bool, tree);