[Bug tree-optimization/126871] New: ICE on valid code at -O{2,3} with -fno-vect-cost-model on x86_64-linux-gnu: verify_ssa failed

[zhendong.su at inf dot ethz.ch via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126871

            Bug ID: 126871
           Summary: ICE on valid code at -O{2,3} with -fno-vect-cost-model
                    on x86_64-linux-gnu: verify_ssa failed
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

Compiler Explorer: https://godbolt.org/z/bzva9MezM

Note:
- fails: trunk
- works: 16.2 and earlier

[823] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/home/suz/suz-local/software/local/gcc-trunk/bin/../libexec/gcc/x86_64-pc-linux-gnu/17.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=c,c++,lto --disable-werror
--disable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 17.0.0 20260814 (experimental) [master r17-1628-gd1c12591336] (GCC) 
[824] % 
[824] % gcctk -O2 -fno-vect-cost-model small.c
small.c: In function ‘j’:
small.c:2:6: error: definition in block 4 does not dominate use in block 5
    2 | void j() {
      |      ^
for SSA_NAME: _14 in statement:
iftmp.4_8 = PHI <a.5_5(3), _14(5)>
PHI argument
_14
for PHI node
iftmp.4_8 = PHI <a.5_5(3), _14(5)>
during GIMPLE pass: slp
small.c:2:6: internal compiler error: verify_ssa failed
0x27d402b internal_error(char const*, ...)
        ../../gcc-trunk/gcc/diagnostic-global-context.cc:787
0x14aef2f verify_ssa(bool, bool)
        ../../gcc-trunk/gcc/tree-ssa.cc:1226
0x10c6584 execute_function_todo
        ../../gcc-trunk/gcc/passes.cc:2107
0x10c6cde execute_todo
        ../../gcc-trunk/gcc/passes.cc:2152
/local/home/suz/suz-local/software/local/gcc-trunk/bin/../libexec/gcc/x86_64-pc-linux-gnu/17.0.0/cc1
-quiet -I /usr/local/include -I /local/suz-local/software/local/include
-imultiarch x86_64-linux-gnu -iprefix
/local/home/suz/suz-local/software/local/gcc-trunk/bin/../lib/gcc/x86_64-pc-linux-gnu/17.0.0/
small.c -quiet -dumpdir a- -dumpbase small.c -dumpbase-ext .c -mtune=generic
-march=x86-64 -O2 -fvect-cost-model=unlimited -o /tmp/ccALaX9G.s
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
[825] % 
[825] % cat small.c
int a, c, d, e, i;
void j() {
  int k, l, m, n, o, p;
  k = (c + d) ^ 1088271051541471734;
  l = k & 1088271051541471734;
  p = ~l;
  o = ~k;
  i = -1719165431;
  m = o & i;
  n = ~m;
  k = n & p;
  e = c - (a ? a : k) + k;
}