[llvm] [VPlan] Introduce scalar loop header in plan, remove VPLiveOut. (PR #109975)

[via llvm-commits]

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@@ -264,6 +264,13 @@ void UnrollState::unrollRecipeByUF(VPRecipeBase &R) {
     return;
 
   if (auto *VPI = dyn_cast<VPInstruction>(&R)) {
+    VPValue *Op0, *Op1;
+    if (match(VPI, m_VPInstruction<VPInstruction::ResumePhi>(m_VPValue(Op0),
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ayalz wrote:

VPInstruction::ResumePhi `isSingleScalar()`, so should probably qualify as only first part used below?

https://github.com/llvm/llvm-project/pull/109975