[llvm] 1e0f814 - Remove a FIXME that will never be fixed since undef is being removed.

[Owen Anderson via llvm-commits]

Author: Owen Anderson
Date: 2023-01-10T21:06:06-07:00
New Revision: 1e0f814e73094d57f9576bdca8fa03fdf02940fb

URL: https://github.com/llvm/llvm-project/commit/1e0f814e73094d57f9576bdca8fa03fdf02940fb
DIFF: https://github.com/llvm/llvm-project/commit/1e0f814e73094d57f9576bdca8fa03fdf02940fb.diff

LOG: Remove a FIXME that will never be fixed since undef is being removed.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D141344

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/BDCE.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Scalar/BDCE.cpp b/llvm/lib/Transforms/Scalar/BDCE.cpp
index 6c2467db79f79..187927b3dede4 100644
--- a/llvm/lib/Transforms/Scalar/BDCE.cpp
+++ b/llvm/lib/Transforms/Scalar/BDCE.cpp
@@ -143,9 +143,8 @@ static bool bitTrackingDCE(Function &F, DemandedBits &DB) {
 
       clearAssumptionsOfUsers(&I, DB);
 
-      // FIXME: In theory we could substitute undef here instead of zero.
-      // This should be reconsidered once we settle on the semantics of
-      // undef, poison, etc.
+      // Substitute all uses with zero. In theory we could use `freeze poison`
+      // instead, but that seems unlikely to be profitable.
       U.set(ConstantInt::get(U->getType(), 0));
       ++NumSimplified;
       Changed = true;