re PR tree-optimization/61441 (ARM aarch64 fails to quiet signaling NaN)

	PR tree-optimization/61441
	* simplify-rtx.c (simplify_const_unary_operation): For
	-fsignaling-nans and sNaN operand, return NULL_RTX rather than
	the sNaN unmodified.

From-SVN: r245620

gcc/ChangeLog

+2017-02-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/61441
+	* simplify-rtx.c (simplify_const_unary_operation): For
+	-fsignaling-nans and sNaN operand, return NULL_RTX rather than
+	the sNaN unmodified.
+
 2017-02-20  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	* Makefile.in (BUILD_SYSTEM_HEADER_DIR): New make variabe.

gcc/simplify-rtx.c

@@ -1889,23 +1889,26 @@ simplify_const_unary_operation (enum rtx_code code, machine_mode mode,
 	case FLOAT_TRUNCATE:
 	  /* Don't perform the operation if flag_signaling_nans is on
 	     and the operand is a signaling NaN.  */
-	  if (!(HONOR_SNANS (mode) && REAL_VALUE_ISSIGNALING_NAN (d)))
-	    d = real_value_truncate (mode, d);
+	  if (HONOR_SNANS (mode) && REAL_VALUE_ISSIGNALING_NAN (d))
+	    return NULL_RTX;
+	  d = real_value_truncate (mode, d);
 	  break;
 	case FLOAT_EXTEND:
-	  /* All this does is change the mode, unless changing
-	     mode class.  */
 	  /* Don't perform the operation if flag_signaling_nans is on
 	     and the operand is a signaling NaN.  */
-	  if (GET_MODE_CLASS (mode) != GET_MODE_CLASS (GET_MODE (op))
-	      && !(HONOR_SNANS (mode) && REAL_VALUE_ISSIGNALING_NAN (d)))
+	  if (HONOR_SNANS (mode) && REAL_VALUE_ISSIGNALING_NAN (d))
+	    return NULL_RTX;
+	  /* All this does is change the mode, unless changing
+	     mode class.  */
+	  if (GET_MODE_CLASS (mode) != GET_MODE_CLASS (GET_MODE (op)))
 	    real_convert (&d, mode, &d);
 	  break;
 	case FIX:
 	  /* Don't perform the operation if flag_signaling_nans is on
 	     and the operand is a signaling NaN.  */
-	  if (!(HONOR_SNANS (mode) && REAL_VALUE_ISSIGNALING_NAN (d)))
-	    real_arithmetic (&d, FIX_TRUNC_EXPR, &d, NULL);
+	  if (HONOR_SNANS (mode) && REAL_VALUE_ISSIGNALING_NAN (d))
+	    return NULL_RTX;
+	  real_arithmetic (&d, FIX_TRUNC_EXPR, &d, NULL);
 	  break;
 	case NOT:
 	  {