[llvm] [VPlan] Fold common edges away in convertPhisToBlends (PR #150368)

[Luke Lau via llvm-commits]

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@@ -238,6 +257,7 @@ void VPPredicator::convertPhisToBlends(VPBasicBlock *VPBB) {
     // be duplications since this is a simple recursive scan, but future
     // optimizations will clean it up.
 
+    VPValue *CommonEdgeMask = findCommonEdgeMask(PhiR);
     SmallVector<VPValue *, 2> OperandsWithMask;
     unsigned NumIncoming = PhiR->getNumIncoming();
     for (unsigned In = 0; In < NumIncoming; In++) {
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lukel97 wrote:

I think we always need to do at least two iterations, because we can't remove the common edge mask until we've gone through every edge mask and checked that they all contain it

https://github.com/llvm/llvm-project/pull/150368