[PATCH] D110922: [LoopPeel] Peel loops with deoptimizing exits

Fri Oct 8 10:53:15 PDT 2021

aeubanks added a comment.

This causes crashes, reverting

  $ ./build/rel/bin/opt -passes=loop-unroll-full /tmp/b.ll -disable-output
  opt: ../../llvm/include/llvm/Support/CFGUpdate.h:87: void llvm::cfg::LegalizeUpdates(ArrayRef<Update<NodePtr>>, SmallVectorImpl<Update<NodePtr>> &, bool, bool) [NodePtr = llvm::BasicBlock *]: Assertion `std::abs(NumInsertions) <= 1 && "Unbalanced operations!"' failed.
  PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
  Stack dump:
  0.      Program arguments: ./build/rel/bin/opt -passes=loop-unroll-full /tmp/b.ll -disable-output
   #0 0x0000000001f01953 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/lib/Support/Unix/Signals.inc:565:13
   #1 0x0000000001eff7ce llvm::sys::RunSignalHandlers() /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/lib/Support/Signals.cpp:98:18
   #2 0x0000000001f01cbf SignalHandler(int) /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/lib/Support/Unix/Signals.inc:407:1
   #3 0x00007f998f9e7140 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14140)
   #4 0x00007f998f4c6ce1 raise ./signal/../sysdeps/unix/sysv/linux/raise.c:51:1
   #5 0x00007f998f4b0537 abort ./stdlib/abort.c:81:7
   #6 0x00007f998f4b040f get_sysdep_segment_value ./intl/loadmsgcat.c:509:8
   #7 0x00007f998f4b040f _nl_load_domain ./intl/loadmsgcat.c:970:34
   #8 0x00007f998f4bf662 (/lib/x86_64-linux-gnu/libc.so.6+0x34662)
   #9 0x0000000001539fd3 AdvancePastEmptyBuckets /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/include/llvm/ADT/DenseMap.h:1281:5
  #10 0x0000000001539fd3 operator++ /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/include/llvm/ADT/DenseMap.h:1271:5
  #11 0x0000000001539fd3 void llvm::cfg::LegalizeUpdates<llvm::BasicBlock*>(llvm::ArrayRef<llvm::cfg::Update<llvm::BasicBlock*> >, llvm::SmallVectorImpl<llvm::cfg::Update<llvm::BasicBlock*> >&, bool, bool) /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/include/llvm/Support/CFGUpdate.h:85:17
  #12 0x0000000001537265 llvm::GraphDiff<llvm::BasicBlock*, false>::GraphDiff(llvm::ArrayRef<llvm::cfg::Update<llvm::BasicBlock*> >, bool) /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/include/llvm/Support/CFGDiff.h:0:5
  #13 0x00000000025a0809 applyUpdates /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/include/llvm/Support/GenericDomTree.h:547:5
  #14 0x00000000025a0809 llvm::peelLoop(llvm::Loop*, unsigned int, llvm::LoopInfo*, llvm::ScalarEvolution*, llvm::DominatorTree*, llvm::AssumptionCache*, bool) /usr/local/google/home/aeubanks/repos/llvm-project/build/rel/../../llvm/lib/Transforms/Utils/LoopPeel.cpp:803:7

F19489873: b.ll <https://reviews.llvm.org/F19489873>

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