[llvm] [LoopPeel] Remove known trip count restriction when peeling last. (PR #140792)

[Florian Hahn via llvm-commits]

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@@ -912,10 +909,19 @@ static void cloneLoopBlocks(
   if (PeelLast) {
     // For the last iteration, we use the value from the latch of the original
     // loop directly.
+    //
+    IRBuilder<> B(InsertTop->getTerminator());
     for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
       PHINode *NewPHI = cast<PHINode>(VMap[&*I]);
-      VMap[&*I] = NewPHI->getIncomingValueForBlock(Latch);
+      PHINode *PN = B.CreatePHI(NewPHI->getType(), 2);
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fhahn wrote:

The new phi is placed in a different block (InsertTop, which is the predecessor of the header of the peeled iteration. It seems cleaner to create a new phi, but I could also move the existing phis and re-set their values if preferred.

https://github.com/llvm/llvm-project/pull/140792