[Bug target/102080] New: [12 Regression] avx512vl related ICE, on firefox-92 gcc ICEs: in expand_insn, at optabs.c:7946

["slyfox at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102080

            Bug ID: 102080
           Summary: [12 Regression] avx512vl related ICE, on firefox-92
                    gcc ICEs: in expand_insn, at optabs.c:7946
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
  Target Milestone: ---

Observed gcc-12 ICE on today's gcc when was building firefox checkout.

I might have reduced it down to something invalid. Here is the minimal
reproducer:

    // cat dec_reconstruct.cc.cc
    #pragma GCC target "avx"
    typedef float __m256 __attribute__((__vector_size__(32)));
    __m256 _mm256_blendv_ps___Y, _mm256_blendv_ps___M, _mm256_mul_ps___A,
        _mm256_mul_ps___B, IfThenElse___trans_tmp_9;
    void IfThenElse(__m256 no) {
      IfThenElse___trans_tmp_9 = __builtin_ia32_blendvps256(
          no, _mm256_blendv_ps___Y, _mm256_blendv_ps___M);
    }
    #pragma GCC target "avx512vl"
    void EncodedFromDisplay() {
      __m256 __trans_tmp_11 = _mm256_mul_ps___A * _mm256_mul_ps___B;
      IfThenElse(__trans_tmp_11);
    }

-O0 works, -O2 fails:

$ /tmp/gcc-c/gcc/xg++ -B/tmp/gcc-c/gcc -c dec_reconstruct.cc.cc -O0

$ /tmp/gcc-c/gcc/xg++ -B/tmp/gcc-c/gcc -c dec_reconstruct.cc.cc -O2
during RTL pass: expand
dec_reconstruct.cc.cc: In function 'void EncodedFromDisplay()':
dec_reconstruct.cc.cc:10:6: internal compiler error: in expand_insn, at
optabs.c:7946
   10 | void EncodedFromDisplay() {
      |      ^~~~~~~~~~~~~~~~~~
0x7f3941d62286 __libc_start_call_main
        ../sysdeps/nptl/libc_start_call_main.h:58
0x7f3941d62337 __libc_start_main_impl
        ../csu/libc-start.c:409
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ /tmp/gcc-c/gcc/xg++ -B/tmp/gcc-c/gcc -v
Reading specs from /tmp/gcc-c/gcc/specs
COLLECT_GCC=/tmp/gcc-c/gcc/xg++
COLLECT_LTO_WRAPPER=/tmp/gcc-c/gcc/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /home/slyfox/dev/git/gcc/configure --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu
--enable-languages=c,c++ --disable-bootstrap --with-multilib-list=m64
--prefix=/tmp/gcc-c/../gcc-native-quick-installed --disable-nls --without-isl
--disable-libsanitizer --disable-libvtv --disable-libgomp
--disable-libstdcxx-pch --disable-libunwind-exceptions CFLAGS='-O1 '
CXXFLAGS='-O1 '
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.0 20210826 (experimental) (GCC)