https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115308
Bug ID: 115308
Summary: std::experimental::simd<char> is not convertible to
NEON intrinsic type with Clang
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: mkretz at gcc dot gnu.org
Reporter: mkretz at gcc dot gnu.org
Target Milestone: ---
Target: arm-*-*, aarch64-*-*
std::experimental::parallelism_v2::__int_for_sizeof<1>() returns 'char' instead
of 'signed char' if __clang__ is defined. With -fno-signed-char that's an
observable bug.
https://github.com/VcDevel/std-simd/commit/2f99e2813fc751d2493ad79bc1aec3ce64c7c49e
is the commit that introduced it (before the merge to libstdc++). "Use char for
1
byte and long long for 8 bytes. This is necessary to match the return vector
type of vector compares."
I'm taking a guess here that this is due to GCC applying
-flax-vector-conversions on vector compare results and Clang probably doesn't
do it. But that still doesn't really justify returning 'char' unconditionally
for trait that is supposed to return a signed integer type.
The mask type issue must be solved differently, so that __int_for_sizeof can
return the right type again.
All releases of GCC are affected.
