[all-commits] [llvm/llvm-project] ddd7d3: [RegAlloc] Fix assertion failure caused by inline ...

[Qi Hu via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ddd7d35c6c2697eec8d665e70d4e1395003cbec9
      https://github.com/llvm/llvm-project/commit/ddd7d35c6c2697eec8d665e70d4e1395003cbec9
  Author: Qi Hu <qi.hu at huawei.com>
  Date:   2023-07-25 (Tue, 25 Jul 2023)

  Changed paths:
    M llvm/lib/CodeGen/RegAllocFast.cpp
    A llvm/test/CodeGen/X86/inline-asm-assertion.ll

  Log Message:
  -----------
  [RegAlloc] Fix assertion failure caused by inline assembly

When inline assembly code requests more registers than available, the
MachineInstr::emitError function in the RegAllocFast pass emits an error
but doesn't stop the pass, and then the compiler crashes later with an
assertion failure. This commit, mimicking the RegAllocGreedy pass, assigns
a random physical register, and therefore avoids the crash after producing
the diagnostic. This problem has been observed for both rustc and clang,
while it doesn't occur in gcc.