[llvm] [VPlan] Create header phis once, after constructing VPlan0 (NFC). (PR #168291)

[Florian Hahn via llvm-commits]

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@@ -2372,8 +2372,10 @@ struct VPFirstOrderRecurrencePHIRecipe : public VPHeaderPHIRecipe {
   VP_CLASSOF_IMPL(VPDef::VPFirstOrderRecurrencePHISC)
 
   VPFirstOrderRecurrencePHIRecipe *clone() override {
-    return new VPFirstOrderRecurrencePHIRecipe(
+    auto *R = new VPFirstOrderRecurrencePHIRecipe(
         cast<PHINode>(getUnderlyingInstr()), *getOperand(0));
+    R->addOperand(getOperand(1));
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fhahn wrote:

Yep, but only exposed now (previosuly we would never clone plans with VPFirstOrderRecurrencePHIRecipe)

https://github.com/llvm/llvm-project/pull/168291