[PATCH] D139275: [SimplifyCFG] `FoldBranchToCommonDest()`: deal with mismatched IV's in PHI's in common successor block

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


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Comment at: llvm/test/Transforms/SimplifyCFG/X86/SpeculativeExec.ll:15
+; CHECK-NEXT:    [[T3:%.*]] = add i32 [[A]], 1
+; CHECK-NEXT:    [[T4:%.*]] = select i1 [[OR_COND]], i32 [[T3]], i32 [[T4_SEL]]
 ; CHECK-NEXT:    [[T5:%.*]] = sub i32 [[T4]], 1
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Looks like this test, and many similar tests regress, where we go from two selects to three selects. And we never seem to recover from this in either the middle end or the back end: https://alive2.llvm.org/ce/z/GjCXkB


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D139275/new/

https://reviews.llvm.org/D139275