[Bug c++/95987] New: Another ice during GIMPLE pass: slp

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95987

            Bug ID: 95987
           Summary: Another ice during GIMPLE pass: slp
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

For this C++ code:

$ cat bug627.cc
int a;
class b {
  void c();
  static int f[];
};
void b::c() {
  for (int d; d; ++d)
    for (int e = 0; e < 6; ++e)
      f[e] = e + 4 << a;
}

compiled on recent gcc trunk, does this:

$ /home/dcb/gcc/results/bin/c++  -c -w -O3 -std=c++14 bug627.cc
bug627.cc: In member function ‘void b::c()’:
bug627.cc:6:6: error: definition in block 3 follows the use
    6 | void b::c() {
      |      ^
for SSA_NAME: a.0_16 in statement:
vect__17.12_53 = vect_cst__12 << a.0_16;
during GIMPLE pass: slp
bug627.cc:6:6: internal compiler error: verify_ssa failed
0x13fa7db verify_ssa(bool, bool)
        ../../trunk.git/gcc/tree-ssa.c:1208
0x108dde5 execute_function_todo
        ../../trunk.git/gcc/passes.c:1992

The bug seems to first occur sometime between 20200624 and 20200625.