fold-const.c (fold_binary): Guard (X-X) -> 0 transformation with !HONOR_NANS and !HONOR_INFINITIES.

	* fold-const.c (fold_binary): Guard (X-X) -> 0 transformation
	with !HONOR_NANS and !HONOR_INFINITIES.
	* simplify-rtx.c (simplify_binary_operation_1): Likewise.

From-SVN: r125652

gcc/ChangeLog

+2007-06-12  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+	* fold-const.c (fold_binary): Guard (X-X) -> 0 transformation
+	with !HONOR_NANS and !HONOR_INFINITIES.
+	* simplify-rtx.c (simplify_binary_operation_1): Likewise.
+
 2007-06-12  Tristan Gingold  <gingold@adacore.com>
 
 	* gcov.c: Comments updated.

gcc/fold-const.c

@@ -9585,7 +9585,10 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 	 Also note that operand_equal_p is always false if an operand
 	 is volatile.  */
 
-      if ((! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)
+      if ((! FLOAT_TYPE_P (type)
+	   || (flag_unsafe_math_optimizations
+	       && !HONOR_NANS (TYPE_MODE (type))
+	       && !HONOR_INFINITIES (TYPE_MODE (type))))
 	  && operand_equal_p (arg0, arg1, 0))
 	return fold_convert (type, integer_zero_node);
 

gcc/simplify-rtx.c

@@ -1772,10 +1772,14 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
     case MINUS:
       /* We can't assume x-x is 0 even with non-IEEE floating point,
 	 but since it is zero except in very strange circumstances, we
-	 will treat it as zero with -funsafe-math-optimizations.  */
+	 will treat it as zero with -funsafe-math-optimizations and
+	 -ffinite-math-only.  */
       if (rtx_equal_p (trueop0, trueop1)
 	  && ! side_effects_p (op0)
-	  && (! FLOAT_MODE_P (mode) || flag_unsafe_math_optimizations))
+	  && (! FLOAT_MODE_P (mode)
+	      || (flag_unsafe_math_optimizations
+		  && !HONOR_NANS (mode)
+		  && !HONOR_INFINITIES (mode))))
 	return CONST0_RTX (mode);
 
       /* Change subtraction from zero into negation.  (0 - x) is the