From 7743badafa68ea15f5762fd9c20321fca564f1aa Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo@fhahn.com>
Date: Sat, 27 Aug 2022 22:06:11 +0100
Subject: [PATCH] [VPlan] Verify that header only contains header phi recipes.

Add verification that VPHeaderPHIRecipes are only in header VPBBs. Also
adds missing checks for VPPointerInductionRecipe to
VPHeaderPHIRecipe::classof.

Split off from D119661.

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D131989
---
 llvm/lib/Transforms/Vectorize/VPlan.h           |  2 ++
 llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp | 39 +++++++++++++++++++++----
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 75a544a..eab1223 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1139,6 +1139,7 @@ public:
            B->getVPDefID() == VPRecipeBase::VPFirstOrderRecurrencePHISC ||
            B->getVPDefID() == VPRecipeBase::VPReductionPHISC ||
            B->getVPDefID() == VPRecipeBase::VPWidenIntOrFpInductionSC ||
+           B->getVPDefID() == VPRecipeBase::VPWidenPointerInductionSC ||
            B->getVPDefID() == VPRecipeBase::VPWidenPHISC;
   }
   static inline bool classof(const VPValue *V) {
@@ -1147,6 +1148,7 @@ public:
            V->getVPValueID() == VPValue::VPVFirstOrderRecurrencePHISC ||
            V->getVPValueID() == VPValue::VPVReductionPHISC ||
            V->getVPValueID() == VPValue::VPVWidenIntOrFpInductionSC ||
+           V->getVPValueID() == VPValue::VPVWidenPointerInductionSC ||
            V->getVPValueID() == VPValue::VPVWidenPHISC;
   }
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp b/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
index 91ab693..34c8149 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanVerifier.cpp
@@ -133,17 +133,38 @@ void VPlanVerifier::verifyHierarchicalCFG(
   verifyRegionRec(TopRegion);
 }
 
-static bool
-verifyVPBasicBlock(const VPBasicBlock *VPBB,
-                   DenseMap<const VPBlockBase *, unsigned> &BlockNumbering) {
-  // Verify that phi-like recipes are at the beginning of the block, with no
-  // other recipes in between.
+// Verify that phi-like recipes are at the beginning of \p VPBB, with no
+// other recipes in between. Also check that only header blocks contain
+// VPHeaderPHIRecipes.
+static bool verifyPhiRecipes(const VPBasicBlock *VPBB) {
   auto RecipeI = VPBB->begin();
   auto End = VPBB->end();
   unsigned NumActiveLaneMaskPhiRecipes = 0;
+  const VPRegionBlock *ParentR = VPBB->getParent();
+  bool IsHeaderVPBB = ParentR && !ParentR->isReplicator() &&
+                      ParentR->getEntryBasicBlock() == VPBB;
   while (RecipeI != End && RecipeI->isPhi()) {
     if (isa<VPActiveLaneMaskPHIRecipe>(RecipeI))
       NumActiveLaneMaskPhiRecipes++;
+
+    if (IsHeaderVPBB && !isa<VPHeaderPHIRecipe>(*RecipeI)) {
+      errs() << "Found non-header PHI recipe in header VPBB";
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+      errs() << ": ";
+      RecipeI->dump();
+#endif
+      return false;
+    }
+
+    if (!IsHeaderVPBB && isa<VPHeaderPHIRecipe>(*RecipeI)) {
+      errs() << "Found header PHI recipe in non-header VPBB";
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+      errs() << ": ";
+      RecipeI->dump();
+#endif
+      return false;
+    }
+
     RecipeI++;
   }
 
@@ -166,6 +187,14 @@ verifyVPBasicBlock(const VPBasicBlock *VPBB,
     }
     RecipeI++;
   }
+  return true;
+}
+
+static bool
+verifyVPBasicBlock(const VPBasicBlock *VPBB,
+                   DenseMap<const VPBlockBase *, unsigned> &BlockNumbering) {
+  if (!verifyPhiRecipes(VPBB))
+    return false;
 
   // Verify that defs in VPBB dominate all their uses. The current
   // implementation is still incomplete.
-- 
2.7.4