[llvm] [LoopIdiomVectorize] Remove redundant DomTreeUpdates (PR #94681)

[David Sherwood via llvm-commits]

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@@ -717,12 +703,8 @@ void LoopIdiomVectorize::transformByteCompare(GetElementPtrInst *GEPA,
   if (FoundBB != EndBB) {
     Value *FoundCmp = Builder.CreateICmpEQ(ByteCmpRes, MaxLen);
     Builder.CreateCondBr(FoundCmp, EndBB, FoundBB);
-    DTU.applyUpdates({{DominatorTree::Insert, CmpBB, FoundBB},
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david-arm wrote:

Given that FoundBB and EndBB appear after CmpBB and we're only calling `DTU.applyUpdates({{DominatorTree::Insert, MismatchEnd, CmpBB}});` above I'm not sure how the dominator tree gets updated about the new paths CmpBB->FoundBB and CmpBB->EndBB? I admit my knowledge of the DTU isn't that great, so I'm probably missing something!

https://github.com/llvm/llvm-project/pull/94681