[PATCH] D78881: [FlattenCFG] Fix `MergeIfRegion` in case then-path is empty

[Jakub Kuderski via Phabricator via llvm-commits]

kuhar accepted this revision.
kuhar added a comment.
This revision is now accepted and ready to land.

I followed the new tests and the patch seems fine to me, but I'd rather someone else took a look too.



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Comment at: llvm/lib/Transforms/Utils/FlattenCFG.cpp:487
   Builder.SetInsertPoint(PBI);
-  Value *NC = Builder.CreateOr(CInst1, CC);
-  PBI->replaceUsesOfWith(CC, NC);
+  if (Invert2) {
+    // If this is a "cmp" instruction, only used for branching (and nowhere
----------------
Is there a better name for `Invert2`? I think until this point it's difficult to tell what it's actually for.


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Comment at: llvm/test/Transforms/Util/flattencfg.ll:32
 ; CHECK-NEXT:    %1 = fcmp ult float %b
-; CHECK-NEXT:    [[COND:%[a-z0-9]+]] = or i1 %0, %1
+; CHECK-NEXT:    [[COND:%[a-z0-9]+]] = and i1 %0, %1
 ; CHECK-NEXT:    br i1 [[COND]], label %bb4, label %bb3
----------------
Good catch!


Repository:
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  https://reviews.llvm.org/D78881/new/

https://reviews.llvm.org/D78881