[Bug target/84786] [miscompilation] vunpcklpd accessing xmm16-22 targeting KNL

[kretz at kde dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84786

--- Comment #11 from Matthias Kretz <kretz at kde dot org> ---
Created attachment 43762
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43762&action=edit
test case that produces incorrect vpsrlw

Compiled with `g++-7 -std=c++17 -O0 -fabi-version=0 -fabi-compat-version=0
-march=knl -o fail fail.cpp`

g++-7 (Ubuntu 7.2.0-1ubuntu1~16.04) 7.2.0

from objdump -d | grep vpsrlw I get:
  56e364:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  56eaf6:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  56f174:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  56f68c:       62 b1 7d 08 d1 c3       vpsrlw %xmm19,%xmm0,%xmm0
  58ef6f:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  58f6f5:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  58fd67:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  590273:       62 b1 7d 08 d1 c3       vpsrlw %xmm19,%xmm0,%xmm0
  59585d:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  595fef:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  596664:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  596b6a:       62 b1 7d 08 d1 c3       vpsrlw %xmm19,%xmm0,%xmm0
  59cb7a:       62 b1 7d 28 d1 c0       vpsrlw %xmm16,%ymm0,%ymm0
  59d39f:       62 b1 7d 28 d1 c1       vpsrlw %xmm17,%ymm0,%ymm0
  59d9fe:       62 b1 7d 28 d1 c2       vpsrlw %xmm18,%ymm0,%ymm0
  59dfc6:       62 b1 7d 28 d1 c3       vpsrlw %xmm19,%ymm0,%ymm0
  5a407c:       62 b1 7d 28 d1 c0       vpsrlw %xmm16,%ymm0,%ymm0
  5a4895:       62 b1 7d 28 d1 c1       vpsrlw %xmm17,%ymm0,%ymm0
  5a4eeb:       62 b1 7d 28 d1 c2       vpsrlw %xmm18,%ymm0,%ymm0
  5a54ad:       62 b1 7d 28 d1 c3       vpsrlw %xmm19,%ymm0,%ymm0
  5be392:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  5bea0b:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  5bef85:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  5bf3be:       62 b1 7d 08 d1 c3       vpsrlw %xmm19,%xmm0,%xmm0
  5d8ae0:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  5d9149:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  5d96b3:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  5d9adc:       62 b1 7d 08 d1 c3       vpsrlw %xmm19,%xmm0,%xmm0
  5de3e7:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  5dea62:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  5defd5:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  5df3fe:       62 b1 7d 08 d1 c3       vpsrlw %xmm19,%xmm0,%xmm0
  5e3cd2:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  5e431b:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  5e4865:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  5e4c6e:       62 b1 7d 08 d1 c3       vpsrlw %xmm19,%xmm0,%xmm0
  5e94bd:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  5e9b18:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  5ea06b:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  5ea474:       62 b1 7d 08 d1 c3       vpsrlw %xmm19,%xmm0,%xmm0
  799710:       c5 f9 d1 c5             vpsrlw %xmm5,%xmm0,%xmm0
  7999a9:       c5 f9 d1 c6             vpsrlw %xmm6,%xmm0,%xmm0
  799e3b:       c5 f9 d1 c7             vpsrlw %xmm7,%xmm0,%xmm0
  79a101:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  79a3c2:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  79a68c:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0
  7a1e51:       c5 f9 d1 c5             vpsrlw %xmm5,%xmm0,%xmm0
  7a20ea:       c5 f9 d1 c6             vpsrlw %xmm6,%xmm0,%xmm0
  7a2579:       c5 f9 d1 c7             vpsrlw %xmm7,%xmm0,%xmm0
  7a283f:       62 b1 7d 08 d1 c0       vpsrlw %xmm16,%xmm0,%xmm0
  7a2b00:       62 b1 7d 08 d1 c1       vpsrlw %xmm17,%xmm0,%xmm0
  7a2dca:       62 b1 7d 08 d1 c2       vpsrlw %xmm18,%xmm0,%xmm0