[llvm] [VPlan] Remove loop region in optimizeForVFAndUF. (PR #108378)

[Florian Hahn via llvm-commits]

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@@ -837,16 +840,42 @@ void VPlanTransforms::optimizeForVFAndUF(VPlan &Plan, ElementCount BestVF,
       !SE.isKnownPredicate(CmpInst::ICMP_ULE, TripCount, C))
     return;
 
-  LLVMContext &Ctx = SE.getContext();
-  auto *BOC = new VPInstruction(
-      VPInstruction::BranchOnCond,
-      {Plan.getOrAddLiveIn(ConstantInt::getTrue(Ctx))}, Term->getDebugLoc());
-
-  SmallVector<VPValue *> PossiblyDead(Term->operands());
   Term->eraseFromParent();
-  for (VPValue *Op : PossiblyDead)
-    recursivelyDeleteDeadRecipes(Op);
-  ExitingVPBB->appendRecipe(BOC);
+  auto *Header = cast<VPBasicBlock>(VectorRegion->getEntry());
+  auto *CanIVTy = Plan.getCanonicalIV()->getScalarType();
+  if (any_of(Header->phis(),
+             IsaPred<VPWidenIntOrFpInductionRecipe, VPReductionPHIRecipe>)) {
+    LLVMContext &Ctx = SE.getContext();
+    auto *BOC = new VPInstruction(
+        VPInstruction::BranchOnCond,
+        {Plan.getOrAddLiveIn(ConstantInt::getTrue(Ctx))}, Term->getDebugLoc());
+    ExitingVPBB->appendRecipe(BOC);
+  } else {
+    for (VPRecipeBase &R : make_early_inc_range(Header->phis())) {
+      auto *P = cast<VPHeaderPHIRecipe>(&R);
+      P->replaceAllUsesWith(P->getStartValue());
+      P->eraseFromParent();
+    }
+
+    VPBlockBase *Preheader = Plan.getVectorPreheader();
+    VPBlockBase *Middle = Plan.getMiddleBlock();
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fhahn wrote:

Done thanks

https://github.com/llvm/llvm-project/pull/108378