Hi!
As I wrote earlier today on gcc-patches, pr61441.c started failing
on i?86-linux when -fsignaling-nans argument has been added to it.
I believe this is because the simplify_const_unary_operation
changes in r231901 were broken, when the operand is a sNaN and
-fsignaling-nans, we want to avoid folding FLOAT_TRUNCATE, FLOAT_EXTEND
and FIX of a sNaN, not just return it unmodified (this is in a switch
that optionally modifies the real value just to create another CONST_DOUBLE
usually in a different mode out from it. This patch instead
returns NULL, which means no simplification.
Bootstrapped/regtested on x86_64-linux and i686-linux, fixes pr61441.c
on the latter, ok for trunk?
2017-02-20 Jakub Jelinek <ja...@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.
--- gcc/simplify-rtx.c.jj 2017-01-01 12:45:37.000000000 +0100
+++ gcc/simplify-rtx.c 2017-02-20 20:02:33.446251366 +0100
@@ -1889,23 +1889,26 @@ simplify_const_unary_operation (enum rtx
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:
{
Jakub
