[Bug tree-optimization/82726] New: ICE in verify_ssa during GIMPLE pass: pcom

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82726

            Bug ID: 82726
           Summary: ICE in verify_ssa during GIMPLE pass: pcom
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: amker at gcc dot gnu.org, rguenth at gcc dot gnu.org
  Target Milestone: ---

This ICE looks quite old (4.7.0+):

$ gcc /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/vect/vect-outer-4e.c
-O3 --param tree-reassoc-width=4 -march=haswell
/home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/vect/vect-outer-4e.c: In
function ‘foo’:
/home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/vect/vect-outer-4e.c:11:1:
error: definition in block 3 follows the use
 foo (){
 ^~~
for SSA_NAME: predreastmp.100_lsm0.119_99 in statement:
predreastmp.102_51 = predreastmp.100_lsm0.119_99;
during GIMPLE pass: pcom
/home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/vect/vect-outer-4e.c:11:1:
internal compiler error: verify_ssa failed
0x1233d5e verify_ssa(bool, bool)
        ../../gcc/tree-ssa.c:1188
0xe39d54 execute_function_todo
        ../../gcc/passes.c:2001
0xe38ccc do_per_function
        ../../gcc/passes.c:1659
0xe39efd execute_todo
        ../../gcc/passes.c:2048