[Bug tree-optimization/87645] New: gcc hangs up on vr_values::vrp_visit_assignment_or_call

[konstantin.vladimirov at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87645

            Bug ID: 87645
           Summary: gcc hangs up on
                    vr_values::vrp_visit_assignment_or_call
           Product: gcc
           Version: 8.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: konstantin.vladimirov at gmail dot com
  Target Milestone: ---

Reproduction (after creduce, sorry for that code):

typedef unsigned a[8];
a b, g;
int c, d, e, f;
int h() {
  unsigned i = 2;
  for (; i < 8; i++)
    b[i] = 0;
  for (; f;) {
    d = 1;
    for (; d < 14; d += 3) {
      e = 0;
      for (; e < 8; e++) {
        i = 2;
        for (; i < 8; i++)
          b[i] = 5 - (c - g[e] + b[i]);
      }
    }
  }
}

Compiler:

> gcc -v

Reading specs from
/apps/gcc/8.1.0/.bin/../lib64/gcc/x86_64-suse-linux/8.1.0/specs
COLLECT_GCC=/apps/gcc/8.1.0/.bin/gcc
COLLECT_LTO_WRAPPER=/apps/gcc/8.1.0/.bin/../libexec/gcc/x86_64-suse-linux/8.1.0/lto-wrapper
Target: x86_64-suse-linux
Configured with: ./configure --prefix=/apps/gcc/8.1.0
--libdir=/apps/gcc/8.1.0/lib64 --libexecdir=/apps/gcc/8.1.0/libexec
--bindir=/apps/gcc/8.1.0/bin --with-isl=/apps/gcc/8.1.0
--with-libelf=/apps/gcc/8.1.0 --with-mpfr=/apps/gcc/8.1.0
--with-gmp=/apps/gcc/8.1.0 --with-mpc=/apps/gcc/8.1.0
--disable-gnu-unique-object --enable-gold=yes --enable-lto
--enable-languages=c,c++,objc,fortran --build=x86_64-suse-linux
--host=x86_64-suse-linux --target=x86_64-suse-linux --enable-libotm
--disable-multilib --disable-bootstrap --disable-libstdcxx-pch
Thread model: posix
gcc version 8.1.0 (GCC)

Try to compile like this:

gcc -S -O3 test.c

gcc hangs up

gcc -S -O2 test.c

passes ok

This might look similar with https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87087
but in this case it doesn't consume too much memory and gdb shows vrp, not
unroll.