https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115161
--- Comment #11 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #10)
> Any of the floating point to integer intrinsics if they have out of range
> value (haven't checked whether floating point to unsigned intrinsic is a
> problem too or not).
> No matter if it is float or double (dunno if _Float16 too, or __bf16), and
> no matter if it is scalar intrinsic (ss/sd etc.) or vector and how many
> vector elements.
> But, this isn't really a regression, GCC has always behaved that way, the
> only thing that actually changed is that perhaps we can constant fold more
> than we used to do in the past.
> When not using intrinsics, IMNSHO we should keep doing what we did before.
Can we restrict them under flag_trapping_math?
.i.e
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 53f54d1d392..b7a770dad60 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -2256,14 +2256,25 @@ simplify_const_unary_operation (enum rtx_code code,
machine_mode mode,
switch (code)
{
case FIX:
+ /* According to IEEE standard, for conversions from floating point to
+ integer. When a NaN or infinite operand cannot be represented in
+ the destination format and this cannot otherwise be indicated, the
+ invalid operation exception shall be signaled. When a numeric
+ operand would convert to an integer outside the range of the
+ destination format, the invalid operation exception shall be
+ signaled if this situation cannot otherwise be indicated. */
if (REAL_VALUE_ISNAN (*x))
- return const0_rtx;
+ return flag_trapping_math ? NULL_RTX : const0_rtx;
+
+ if (REAL_VALUE_ISINF (*x) && flag_trapping_math)
+ return NULL_RTX;
/* Test against the signed upper bound. */
wmax = wi::max_value (width, SIGNED);
real_from_integer (&t, VOIDmode, wmax, SIGNED);
if (real_less (&t, x))
- return immed_wide_int_const (wmax, mode);
+ return (flag_trapping_math
+ ? NULL_RTX : immed_wide_int_const (wmax, mode));
/* Test against the signed lower bound. */
wmin = wi::min_value (width, SIGNED);
@@ -2276,13 +2287,17 @@ simplify_const_unary_operation (enum rtx_code code,
machine_mode mode,
case UNSIGNED_FIX:
if (REAL_VALUE_ISNAN (*x) || REAL_VALUE_NEGATIVE (*x))
- return const0_rtx;
+ return flag_trapping_math ? NULL_RTX : const0_rtx;
+
+ if (REAL_VALUE_ISINF (*x) && flag_trapping_math)
+ return NULL_RTX;
/* Test against the unsigned upper bound. */
wmax = wi::max_value (width, UNSIGNED);
real_from_integer (&t, VOIDmode, wmax, UNSIGNED);
if (real_less (&t, x))
- return immed_wide_int_const (wmax, mode);
+ return (flag_trapping_math
+ ? NULL_RTX : immed_wide_int_const (wmax, mode));
return immed_wide_int_const (real_to_integer (x, &fail, width),
