https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54939
--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
With AVX2 we indeed generate
.L4:
vmovupd (%rdx,%rax), %ymm3
addl $1, %r9d
vpermpd $177, %ymm3, %ymm4
vmovapd %ymm3, %ymm2
vmulpd %ymm6, %ymm4, %ymm4
vfmsub132pd %ymm5, %ymm4, %ymm2
vfmadd132pd %ymm5, %ymm4, %ymm3
vshufpd $10, %ymm3, %ymm2, %ymm2
vaddpd (%rcx,%rax), %ymm2, %ymm2
vmovupd %ymm2, (%rcx,%rax)
addq $32, %rax
cmpl %esi, %r9d
jb .L4
thus either there is no addsub for %ymm or there is insufficient pattern
support
for it. Note that with AVX2 the above is what is generated even with the cost
model as it's now considered a profitable vectorization.
