[Bug c++/87469] New: ice in record_estimate, at tree-ssa-loop-niter.c:3271

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87469

            Bug ID: 87469
           Summary: ice in record_estimate, at tree-ssa-loop-niter.c:3271
           Product: gcc
           Version: 8.0
            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++ source code:

long a;
struct c {
  void d(unsigned f) {
    long e = f;
    while (e & e - 1)
      e &= e - 1;
    a = e;
  }
};
void g() {
  c b;
  b.d(4 + 2);
}

compiled by recent gcc trunk and compiler flag -O2, does this:

$ ~/gcc/results/bin/gcc -c -w -O2 bug466.cc
during GIMPLE pass: cunrolli
bug466.cc: In function ‘void g()’:
bug466.cc:10:6: internal compiler error: in record_estimate, at
tree-ssa-loop-niter.c:3271
10 | void g() {
   |      ^
0x10bc8da record_estimate
        ../../trunk/gcc/tree-ssa-loop-niter.c:3271
0x10c391b estimate_numbers_of_iterations(loop*)
        ../../trunk/gcc/tree-ssa-loop-niter.c:4122
0x10c4c0c estimate_numbers_of_iterations(function*)
        ../../trunk/gcc/tree-ssa-loop-niter.c:4342
0x109e88e tree_unroll_loops_completely
        ../../trunk/gcc/tree-ssa-loop-ivcanon.c:1424

The problem seems to first occur somewhere between revisions
261000 and 262000.