libstdc++: Don't fail if math_errhandling is not defined
Commit Message
Tested on x86_64-linux and powerpc64le-linux. This fixes the powerpc64le-linux
failure Jonathan reported. OK for trunk?
Older glibc does not define math_errhandling with -ffast-math, in which
case floating-point exceptions are not used.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
* include/experimental/bits/simd.h (__floating_point_flags): Do
not rely on the presence of the math_errhandling macro.
---
libstdc++-v3/include/experimental/bits/simd.h | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
--
──────────────────────────────────────────────────────────────────────────
Dr. Matthias Kretz https://mattkretz.github.io
GSI Helmholtz Centre for Heavy Ion Research https://gsi.de
stdₓ::simd
──────────────────────────────────────────────────────────────────────────
Comments
On Mon, 17 Jan 2022 at 10:22, Matthias Kretz <m.kretz@gsi.de> wrote:
> Tested on x86_64-linux and powerpc64le-linux. This fixes the
> powerpc64le-linux
> failure Jonathan reported. OK for trunk?
>
OK, thanks.
>
> Older glibc does not define math_errhandling with -ffast-math, in which
> case floating-point exceptions are not used.
>
> Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
>
> libstdc++-v3/ChangeLog:
>
> * include/experimental/bits/simd.h (__floating_point_flags): Do
> not rely on the presence of the math_errhandling macro.
> ---
> libstdc++-v3/include/experimental/bits/simd.h | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
>
> --
> ──────────────────────────────────────────────────────────────────────────
> Dr. Matthias Kretz https://mattkretz.github.io
> GSI Helmholtz Centre for Heavy Ion Research https://gsi.de
> stdₓ::simd
> ──────────────────────────────────────────────────────────────────────────
@@ -283,11 +283,20 @@ constexpr inline bool __have_power_vmx = __have_power_vsx;
namespace __detail
{
+ constexpr bool __handle_fpexcept =
+#ifdef math_errhandling
+ math_errhandling & MATH_ERREXCEPT;
+#elif defined __FAST_MATH__
+ false;
+#else
+ true;
+#endif
+
constexpr std::uint_least64_t
__floating_point_flags()
{
std::uint_least64_t __flags = 0;
- if constexpr (math_errhandling & MATH_ERREXCEPT)
+ if constexpr (__handle_fpexcept)
__flags |= 1;
#ifdef __FAST_MATH__
__flags |= 1 << 1;