https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90073
--- Comment #2 from Rodrigo <rcc.dark at gmail dot com> ---
(In reply to H.J. Lu from comment #1)
> The problem is with the default -mtune=generic.
>
> [hjl@gnu-cfl-1 gcc]$ cat /tmp/foo.cc
> #include <x86intrin.h>
>
> using data = long long __attribute__((vector_size(64)));
> void f(data& a, const data& x1, const data& x2) {
> a ^= x1 ^ x2;
> }
> [hjl@gnu-cfl-1 gcc]$ ./xgcc -B./ -O3 -mtune=skylake -mavx2 /tmp/foo.cc -S
>
> [hjl@gnu-cfl-1 gcc]$ cat foo.s
> .file "foo.cc"
> .text
> .p2align 4
> .globl _Z1fRDv8_xRKS_S2_
> .type _Z1fRDv8_xRKS_S2_, @function
> _Z1fRDv8_xRKS_S2_:
> .LFB5519:
> .cfi_startproc
> pushq %rbp
> .cfi_def_cfa_offset 16
> .cfi_offset 6, -16
> movq %rsp, %rbp
> .cfi_def_cfa_register 6
> andq $-64, %rsp
> subq $200, %rsp
> vmovdqa (%rsi), %ymm2
> vmovdqa 32(%rsi), %ymm0
> vpxor (%rdx), %ymm2, %ymm1
> vpxor 32(%rdx), %ymm0, %ymm0
> vpxor (%rdi), %ymm1, %ymm1
> vpxor 32(%rdi), %ymm0, %ymm0
> vmovaps %ymm1, (%rdi)
> vmovaps %ymm0, 32(%rdi)
> vzeroupper
> leave
> .cfi_def_cfa 7, 8
> ret
> .cfi_endproc
> .LFE5519:
> .size _Z1fRDv8_xRKS_S2_, .-_Z1fRDv8_xRKS_S2_
> .ident "GCC: (GNU) 9.0.1 20190412 (experimental)"
> .section .note.GNU-stack,"",@progbits
> [hjl@gnu-cfl-1 gcc]$
Hi! Using -mtune=skylake or -mtune=haswell doesn't fix the problem in my
installation (GCC 8.2, MingW64) or in GodBolt (8.2, 8.3 and trunk). Do you know
why could it be?
