[llvm] [VPlan] Fix header phi VPInstruction verification. NFC (PR #151472)

[Ramkumar Ramachandra via llvm-commits]

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@@ -287,6 +287,38 @@ TEST_F(VPVerifierTest, BlockOutsideRegionWithParent) {
 #endif
 }
 
+TEST_F(VPVerifierTest, NonHeaderPHIInHeader) {
+  VPlan &Plan = getPlan();
+  VPValue *Zero = Plan.getOrAddLiveIn(ConstantInt::get(Type::getInt32Ty(C), 0));
+  auto *CanIV = new VPCanonicalIVPHIRecipe(Zero, {});
+  VPInstruction *BranchOnCond =
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artagnon wrote:

I'm happy to just set an example in this test; cleaning up the rest is optional.

https://github.com/llvm/llvm-project/pull/151472