[llvm] 08c5944 - [VPlan] Fix header phi VPInstruction verification. NFC (#151472)

[via llvm-commits]

Author: Luke Lau
Date: 2025-07-31T23:09:20+08:00
New Revision: 08c5944222175e2530b1bd51c07c99fb08a24675

URL: https://github.com/llvm/llvm-project/commit/08c5944222175e2530b1bd51c07c99fb08a24675
DIFF: https://github.com/llvm/llvm-project/commit/08c5944222175e2530b1bd51c07c99fb08a24675.diff

LOG: [VPlan] Fix header phi VPInstruction verification. NFC (#151472)

Noticed this when checking the invariant that all phis in the header
block must be header phis. I think there's a missing set of parentheses
here, since otherwise it only cast<VPInstruction> when RecipeI isn't a
VPInstruction.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
    llvm/unittests/Transforms/Vectorize/VPlanVerifierTest.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp b/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
index 57d01cbefbe26..5fbff69d60749 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
@@ -79,9 +79,8 @@ bool VPlanVerifier::verifyPhiRecipes(const VPBasicBlock *VPBB) {
     if (isa<VPActiveLaneMaskPHIRecipe>(RecipeI))
       NumActiveLaneMaskPhiRecipes++;
 
-    if (IsHeaderVPBB && !isa<VPHeaderPHIRecipe, VPWidenPHIRecipe>(*RecipeI) &&
-        !isa<VPInstruction>(*RecipeI) &&
-        cast<VPInstruction>(RecipeI)->getOpcode() == Instruction::PHI) {
+    if (IsHeaderVPBB &&
+        !isa<VPHeaderPHIRecipe, VPWidenPHIRecipe, VPPhi>(*RecipeI)) {
       errs() << "Found non-header PHI recipe in header VPBB";
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
       errs() << ": ";

diff  --git a/llvm/unittests/Transforms/Vectorize/VPlanVerifierTest.cpp b/llvm/unittests/Transforms/Vectorize/VPlanVerifierTest.cpp
index 6214ea3a7dc74..20912200bf653 100644
--- a/llvm/unittests/Transforms/Vectorize/VPlanVerifierTest.cpp
+++ b/llvm/unittests/Transforms/Vectorize/VPlanVerifierTest.cpp
@@ -287,6 +287,37 @@ 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, {});
+  auto *BranchOnCond = new VPInstruction(VPInstruction::BranchOnCond, {CanIV});
+
+  VPBasicBlock *VPBB1 = Plan.getEntry();
+  VPBasicBlock *VPBB2 = Plan.createVPBasicBlock("header");
+
+  VPBB2->appendRecipe(CanIV);
+
+  PHINode *PHINode = PHINode::Create(Type::getInt32Ty(C), 2);
+  auto *IRPhi = new VPIRPhi(*PHINode);
+  VPBB2->appendRecipe(IRPhi);
+  VPBB2->appendRecipe(BranchOnCond);
+
+  VPRegionBlock *R1 = Plan.createVPRegionBlock(VPBB2, VPBB2, "R1");
+  VPBlockUtils::connectBlocks(VPBB1, R1);
+  VPBlockUtils::connectBlocks(R1, Plan.getScalarHeader());
+
+#if GTEST_HAS_STREAM_REDIRECTION
+  ::testing::internal::CaptureStderr();
+#endif
+  EXPECT_FALSE(verifyVPlanIsValid(Plan));
+#if GTEST_HAS_STREAM_REDIRECTION
+  EXPECT_STREQ(
+      "Found non-header PHI recipe in header VPBB: IR   <badref> = phi i32 \n",
+      ::testing::internal::GetCapturedStderr().c_str());
+#endif
+}
+
 class VPIRVerifierTest : public VPlanTestIRBase {};
 
 TEST_F(VPIRVerifierTest, testVerifyIRPhi) {