[PATCH] D27582: Avoid infinite loops in branch folding

[Andy Kaylor via Phabricator via llvm-commits]

andrew.w.kaylor updated this revision to Diff 80974.
andrew.w.kaylor added a comment.

I moved the isEHPad() check, as suggested.

I was able to reduce the test case a little more.  The arguments to g() were only necessary to prevent a tail call optimization.  Simply removing 'tail' from the call instruction dealt with that.  I was also able to remove a few of the switch statement entries and simplify the control flow slightly.  The remaining complexity is necessary to prevent intermediate passes (I think mostly the instruction selector) from simplifying a few remaining branches and reordering blocks such that the conditions for the failure are no longer met.

I updated the comments to better explain the failure condition a bit more.


Repository:
  rL LLVM

https://reviews.llvm.org/D27582

Files:
  lib/CodeGen/BranchFolding.cpp
  test/CodeGen/WinEH/wineh-noret-cleanup.ll
  test/CodeGen/X86/branchfolding-catchpads.ll

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