https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101142
Bug ID: 101142
Summary: [11/12 regression] Regression due to supporting
bitwise operators on AVX512 masks.
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: crazylht at gmail dot com
Target Milestone: ---
Host: x86_64-pc-linux-gnu
Target: x86_64-*-* i?86-*-*
Created attachment 51040
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51040&action=edit
test.cpp
options to reproduce regression: g++ byteswap.cpp test.cpp -march=native -O3
-DDTYPE32
The regression is due to r11-2796-g388cb292a94f98a276548cd6ce01285cf36d17df
which supports bitwise operator for avx512 masks. In byteswap.cpp there're a
lot of bitwise operations, the register pressure is very high, so LRA allocate
some bitwise operations to mask registers to avoid spills, the problem is mask
bitwise instructions has 1/4 throught of those gpr versions which causes the
regression.
