re PR middle-end/31530 (Incorrect folding of multiplication and sign change when…

re PR middle-end/31530 (Incorrect folding of multiplication and sign change when followed by an addition)

2007-04-11  Richard Guenther  <rguenther@suse.de>

	PR middle-end/31530
	* simplify-rtx.c (simplify_binary_operation_1): Do not simplify
	a * -b + c as c - a * b if we honor sign dependent rounding.

From-SVN: r123715

gcc/ChangeLog

+2007-04-11  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/31530
+	* simplify-rtx.c (simplify_binary_operation_1): Do not simplify
+	a * -b + c as c - a * b if we honor sign dependent rounding.
+
 2007-04-11  Bernd Schmidt  <bernd.schmidt@analog.com>
 
 	* config/bfin/bfin-protos.h (bfin_expand_movmem): Renamed from

gcc/simplify-rtx.c

@@ -1688,7 +1688,8 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
 							 XEXP (op0, 1)));
 
       /* Canonicalize (plus (mult (neg B) C) A) to (minus A (mult B C)).  */
-      if (GET_CODE (op0) == MULT
+      if (!HONOR_SIGN_DEPENDENT_ROUNDING (mode)
+	  && GET_CODE (op0) == MULT
 	  && GET_CODE (XEXP (op0, 0)) == NEG)
 	{
 	  rtx in1, in2;
@@ -1916,7 +1917,8 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
 	return reversed;
 
       /* Canonicalize (minus A (mult (neg B) C)) to (plus (mult B C) A).  */
-      if (GET_CODE (op1) == MULT
+      if (!HONOR_SIGN_DEPENDENT_ROUNDING (mode)
+	  && GET_CODE (op1) == MULT
 	  && GET_CODE (XEXP (op1, 0)) == NEG)
 	{
 	  rtx in1, in2;
@@ -1931,7 +1933,8 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
 
       /* Canonicalize (minus (neg A) (mult B C)) to
 	 (minus (mult (neg B) C) A).  */
-      if (GET_CODE (op1) == MULT
+      if (!HONOR_SIGN_DEPENDENT_ROUNDING (mode)
+	  && GET_CODE (op1) == MULT
 	  && GET_CODE (op0) == NEG)
 	{
 	  rtx in1, in2;