[Bug target/101142] New: [11/12 regression] Regression due to supporting bitwise operators on AVX512 masks.

[crazylht at gmail dot com]

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.