PHI nodes not grouped at top of basic block!

[regehr]

int a[], f[];
int b, c, d;
long e;
void g() {
  for (; a <= 6; b++) {
    c = 6;
    for (; c >= 0; c--) {
      d = 6;
      for (; d >= 0; d--)
        f[d] = f >= --e < d;
    }
  }
}

compiled like this:

SOUPER_VERIFY=1 SOUPER_DISABLE_LLVM_PEEPHOLES=true SOUPER_ENUMERATIVE_SYNTHESIS_MAX_INSTS=1 ~/souper-regehr/build/sclang -O3 foo.c

ends up with:

PHI nodes not grouped at top of basic block!
  %inc.lcssa = phi i32 [ %inc, %for.inc13 ]
label %for.cond.for.end14_crit_edge
fatal error: error in backend: module broken after (and probably by) Souper
clang-11: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 11.0.0 (https://github.com/regehr/llvm-project.git cbd3118ced344b1c1d7b7023a13abdbc68ba5624)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/regehr/souper-regehr/third_party/llvm-Debug-install/bin
clang-11: note: diagnostic msg: 
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PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-11: note: diagnostic msg: /tmp/foo-4edb20.c
clang-11: note: diagnostic msg: /tmp/foo-4edb20.sh
clang-11: note: diagnostic msg: 

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