https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71300
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |jakub at gcc dot gnu.org
Resolution|--- |INVALID
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
???
At least reading to 0.9.8 version of the ABI pdf, I see for YMM1 class:
sizeof (bytes) VLEN=2 VLEN=4 VLEN=8 VLEN=16
...
any-type * 4/8 1*MI128/ 1*MI128/ 2*MI128/ 4*MI128/
any-type (*)() 1*MI128 2*MI128 4*MI128 8*MI128
...
double 8 1*MD128 1*MD256 2*MD256 4*MD256
The characteristic type is double in this function, therefore for YMM1 class
(letter c) this function is VLEN=4, which means the first argument is passed
in __m256d (holding 4 doubles) and the second argument is passed in a pair of
__m128i (each holding 2 pointers).
This is because AVX generally doesn't support 256-bit integer vector
operations.
If you look at YMM2 class instead, pointers are passed in __m256i instead (for
VLEN=4 and above).
