re PR tree-optimization/53501 (scev introduces signed overflow)

	PR middle-end/53501
	* fold-const.c (fold_binary_loc): Refine previous change.
testsuite/
	* c-c++-common/restrict-2.c: Revert previous change.

From-SVN: r188118

gcc/ChangeLog

+2012-06-01  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR middle-end/53501
+	* fold-const.c (fold_binary_loc): Refine previous change.
+
 2012-06-01  Olivier Hainque  <hainque@adacore.com>
 
 	* config/rs6000/vxworks.h (SUBSUBTARGET_OVERRIDE_OPTIONS): Restore

gcc/fold-const.c

@@ -10042,15 +10042,18 @@ fold_binary_loc (location_t loc,
 	    }
 	}
 
-      /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
-	 same or one.  Make sure type is not saturating.
-	 fold_plusminus_mult_expr will re-associate.  */
-      if ((TREE_CODE (op0) == MULT_EXPR
-	   || TREE_CODE (op1) == MULT_EXPR)
+      /* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the same or
+	 one.  Make sure the type is not saturating and has the signedness of
+	 the stripped operands, as fold_plusminus_mult_expr will re-associate.
+	 ??? The latter condition should use TYPE_OVERFLOW_* flags instead.  */
+      if ((TREE_CODE (arg0) == MULT_EXPR
+	   || TREE_CODE (arg1) == MULT_EXPR)
 	  && !TYPE_SATURATING (type)
+	  && TYPE_UNSIGNED (type) == TYPE_UNSIGNED (TREE_TYPE (arg0))
+	  && TYPE_UNSIGNED (type) == TYPE_UNSIGNED (TREE_TYPE (arg1))
 	  && (!FLOAT_TYPE_P (type) || flag_associative_math))
         {
-	  tree tem = fold_plusminus_mult_expr (loc, code, type, op0, op1);
+	  tree tem = fold_plusminus_mult_expr (loc, code, type, arg0, arg1);
 	  if (tem)
 	    return tem;
 	}
@@ -10665,15 +10668,18 @@ fold_binary_loc (location_t loc,
 	  && (tem = distribute_real_division (loc, code, type, arg0, arg1)))
 	return tem;
 
-      /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the
-	 same or one.  Make sure type is not saturating.
-	 fold_plusminus_mult_expr will re-associate.  */
-      if ((TREE_CODE (op0) == MULT_EXPR
-	   || TREE_CODE (op1) == MULT_EXPR)
+      /* Handle (A1 * C1) - (A2 * C2) with A1, A2 or C1, C2 being the same or
+	 one.  Make sure the type is not saturating and has the signedness of
+	 the stripped operands, as fold_plusminus_mult_expr will re-associate.
+	 ??? The latter condition should use TYPE_OVERFLOW_* flags instead.  */
+      if ((TREE_CODE (arg0) == MULT_EXPR
+	   || TREE_CODE (arg1) == MULT_EXPR)
 	  && !TYPE_SATURATING (type)
+	  && TYPE_UNSIGNED (type) == TYPE_UNSIGNED (TREE_TYPE (arg0))
+	  && TYPE_UNSIGNED (type) == TYPE_UNSIGNED (TREE_TYPE (arg1))
 	  && (!FLOAT_TYPE_P (type) || flag_associative_math))
         {
-	  tree tem = fold_plusminus_mult_expr (loc, code, type, op0, op1);
+	  tree tem = fold_plusminus_mult_expr (loc, code, type, arg0, arg1);
 	  if (tem)
 	    return tem;
 	}

gcc/testsuite/ChangeLog

+2012-06-01  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* c-c++-common/restrict-2.c: Revert previous change.
+
 2012-06-01  Jason Merrill  <jason@redhat.com>
 
 	PR c++/53137

gcc/testsuite/c-c++-common/restrict-2.c

@@ -10,5 +10,5 @@ void foo (float * __restrict__ a, float * __restrict__ b, int n, int j)
 
 /* We should move the RHS of the store out of the loop.  */
 
-/* { dg-final { scan-tree-dump-times "Moving statement" 10 "lim1" } } */
+/* { dg-final { scan-tree-dump-times "Moving statement" 11 "lim1" } } */
 /* { dg-final { cleanup-tree-dump "lim1" } } */