[PATCH] Fix PR34070, wrong folding

[Richard Guenther]

I'll commit this as soon as bootstrap/testing has finished.

Richard.


2007-11-12  Richard Guenther  <rguenther@suse.de>

	PR middle-end/34070
	* fold-const.c (fold_binary): If testing for non-negative
	operands with tree_expr_nonnegative_warnv_p make sure to
	use op0 which has all (sign) conversions retained.

	* gcc.c-torture/execute/pr34070-1.c: New testcase.
	* gcc.c-torture/execute/pr34070-2.c: Likewise.

Index: fold-const.c
===================================================================
*** fold-const.c	(revision 130096)
--- fold-const.c	(working copy)
*************** fold_binary (enum tree_code code, tree t
*** 11202,11208 ****
        strict_overflow_p = false;
        if (TREE_CODE (arg1) == LSHIFT_EXPR
  	  && (TYPE_UNSIGNED (type)
! 	      || tree_expr_nonnegative_warnv_p (arg0, &strict_overflow_p)))
  	{
  	  tree sval = TREE_OPERAND (arg1, 0);
  	  if (integer_pow2p (sval) && tree_int_cst_sgn (sval) > 0)
--- 11202,11208 ----
        strict_overflow_p = false;
        if (TREE_CODE (arg1) == LSHIFT_EXPR
  	  && (TYPE_UNSIGNED (type)
! 	      || tree_expr_nonnegative_warnv_p (op0, &strict_overflow_p)))
  	{
  	  tree sval = TREE_OPERAND (arg1, 0);
  	  if (integer_pow2p (sval) && tree_int_cst_sgn (sval) > 0)
*************** fold_binary (enum tree_code code, tree t
*** 11320,11326 ****
        strict_overflow_p = false;
        if ((code == TRUNC_MOD_EXPR || code == FLOOR_MOD_EXPR)
  	  && (TYPE_UNSIGNED (type)
! 	      || tree_expr_nonnegative_warnv_p (arg0, &strict_overflow_p)))
  	{
  	  tree c = arg1;
  	  /* Also optimize A % (C << N)  where C is a power of 2,
--- 11320,11326 ----
        strict_overflow_p = false;
        if ((code == TRUNC_MOD_EXPR || code == FLOOR_MOD_EXPR)
  	  && (TYPE_UNSIGNED (type)
! 	      || tree_expr_nonnegative_warnv_p (op0, &strict_overflow_p)))
  	{
  	  tree c = arg1;
  	  /* Also optimize A % (C << N)  where C is a power of 2,
Index: testsuite/gcc.c-torture/execute/pr34070-1.c
===================================================================
*** testsuite/gcc.c-torture/execute/pr34070-1.c	(revision 0)
--- testsuite/gcc.c-torture/execute/pr34070-1.c	(revision 0)
***************
*** 0 ****
--- 1,13 ----
+ extern void abort (void);
+ 
+ int f(unsigned int x)
+ {
+     return ((int)x) % 4;
+ }
+ 
+ int main()
+ {
+   if (f(-1) != -1)
+     abort ();
+   return 0;
+ }
Index: testsuite/gcc.c-torture/execute/pr34070-2.c
===================================================================
*** testsuite/gcc.c-torture/execute/pr34070-2.c	(revision 0)
--- testsuite/gcc.c-torture/execute/pr34070-2.c	(revision 0)
***************
*** 0 ****
--- 1,13 ----
+ extern void abort (void);
+ 
+ int f(unsigned int x, int n)
+ {
+     return ((int)x) / (1 << n);
+ }
+ 
+ int main()
+ {
+   if (f(-1, 1) != 0)
+     abort ();
+   return 0;
+ }