[PATCH] D116766: [SCEV] Sequential/in-order `UMin` expression

[Nathan Chancellor via Phabricator via llvm-commits]

nathanchance added a comment.

Just in case it is something different that the Chromium report, I see an assertion failure while building the Linux kernel. Reduced reproducer:

  $ cat route.i
  struct snd_pcm_plugin_channel {
    int enabled : 1;
  } snd_pcm_area_copy(), *zero_areas_dvp;
  int route_transfer_plugin_1_0, route_transfer_plugin_0_0;
  void route_transfer() {
    int nsrcs, ndsts, dst;
    nsrcs = route_transfer_plugin_0_0;
    ndsts = route_transfer_plugin_1_0;
    dst = 0;
    for (; dst < ndsts && dst < nsrcs; ++dst)
      snd_pcm_area_copy();
    ndsts = dst;
    dst = 0;
    for (; dst < ndsts; ++dst)
      zero_areas_dvp->enabled = 0;
  }
  
  $ clang --target=aarch64-linux-gnu -O1 -c -o /dev/null route.i
  
  $ clang --target=aarch64-linux-gnu -O2 -c -o /dev/null route.i
  Unknown SCEV type!
  UNREACHABLE executed at /home/nathan/cbl/github/tc-build/llvm-project/llvm/lib/Analysis/ScalarEvolution.cpp:9299!
  ...


Repository:
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