https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96654
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu.org,
| |rsandifo at gcc dot gnu.org
Blocks| |53947
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
The pattern is exercised directly by BB vectorization only, loop vectorization
still uses a fixed vector size. Still the assembly shows basically the same
code when doing BB vectorization only:
f:
.LFB0:
.cfi_startproc
vmovupd (%rdi), %xmm1
vinsertf128 $0x1, 16(%rdi), %ymm1, %ymm0
vcvttpd2dqy %ymm0, %xmm0
vmovdqu %xmm0, (%rsi)
vzeroupper
ret
this is probably because of some tuning (split unaligned loads, not using
a memory operand for vcvttpd2dqy).
With -O3 -fno-tree-loop-vectorize -march=core-avx2 I get
f:
.LFB0:
.cfi_startproc
vcvttpd2dqy (%rdi), %xmm0
vmovdqu %xmm0, (%rsi)
ret
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
