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[VPlan] Move getCanonicalIV to VPRegionBlock (NFC). #163020

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[VPlan] Move getCanonicalIV to VPRegionBlock (NFC). #163020

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@fhahn fhahn commented Oct 11, 2025

The canonical IV is tied to region blocks; move getCanonicalIV there and update all users.

@fhahn fhahn requested review from aniragil, ayalz and rengolin October 11, 2025 21:17
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llvmbot commented Oct 11, 2025

@llvm/pr-subscribers-llvm-transforms

Author: Florian Hahn (fhahn)

Changes

The canonical IV is tied to region blocks; move getCanonicalIV there and update all users.

Full diff: https://github.com/llvm/llvm-project/pull/163020.diff

7 Files Affected:

  • (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+12-11)
  • (modified) llvm/lib/Transforms/Vectorize/VPlan.h (+10-10)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp (+9-6)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp (+2-1)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+31-23)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp (+2-1)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanUtils.cpp (+6-3)
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index e62d57e6920b7..7a041fda07321 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8242,12 +8242,12 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(
   // count is >= increment and a multiple of the increment.
   bool HasNUW = !IVUpdateMayOverflow || Style == TailFoldingStyle::None;
   if (!HasNUW) {
-    auto *IVInc = Plan->getVectorLoopRegion()
-                      ->getExitingBasicBlock()
-                      ->getTerminator()
-                      ->getOperand(0);
-    assert(match(IVInc, m_VPInstruction<Instruction::Add>(
-                            m_Specific(Plan->getCanonicalIV()), m_VPValue())) &&
+    VPRegionBlock *LoopRegion = Plan->getVectorLoopRegion();
+    auto *IVInc =
+        LoopRegion->getExitingBasicBlock()->getTerminator()->getOperand(0);
+    assert(match(IVInc,
+                 m_VPInstruction<Instruction::Add>(
+                     m_Specific(LoopRegion->getCanonicalIV()), m_VPValue())) &&
            "Did not find the canonical IV increment");
     cast<VPRecipeWithIRFlags>(IVInc)->dropPoisonGeneratingFlags();
   }
@@ -8377,8 +8377,8 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(
   for (VPValue *Old : Old2New.keys())
     Old->getDefiningRecipe()->eraseFromParent();
 
-  assert(isa<VPRegionBlock>(Plan->getVectorLoopRegion()) &&
-         !Plan->getVectorLoopRegion()->getEntryBasicBlock()->empty() &&
+  assert(isa<VPRegionBlock>(LoopRegion) &&
+         !LoopRegion->getEntryBasicBlock()->empty() &&
          "entry block must be set to a VPRegionBlock having a non-empty entry "
          "VPBasicBlock");
 
@@ -9320,8 +9320,9 @@ static void preparePlanForMainVectorLoop(VPlan &MainPlan, VPlan &EpiPlan) {
   if (ResumePhiIter == MainScalarPH->phis().end()) {
     VPBuilder ScalarPHBuilder(MainScalarPH, MainScalarPH->begin());
     ResumePhi = ScalarPHBuilder.createScalarPhi(
-        {VectorTC, MainPlan.getCanonicalIV()->getStartValue()}, {},
-        "vec.epilog.resume.val");
+        {VectorTC,
+         MainPlan.getVectorLoopRegion()->getCanonicalIV()->getStartValue()},
+        {}, "vec.epilog.resume.val");
   } else {
     ResumePhi = cast<VPPhi>(&*ResumePhiIter);
     if (MainScalarPH->begin() == MainScalarPH->end())
@@ -9350,7 +9351,7 @@ static SmallVector<Instruction *> preparePlanForEpilogueVectorLoop(
 
   // Ensure that the start values for all header phi recipes are updated before
   // vectorizing the epilogue loop.
-  VPCanonicalIVPHIRecipe *IV = Plan.getCanonicalIV();
+  VPCanonicalIVPHIRecipe *IV = VectorLoop->getCanonicalIV();
   // When vectorizing the epilogue loop, the canonical induction start
   // value needs to be changed from zero to the value after the main
   // vector loop. Find the resume value created during execution of the main
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index fb696bea671af..8db626fe9bf58 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -4066,6 +4066,16 @@ class LLVM_ABI_FOR_TEST VPRegionBlock : public VPBlockBase {
   /// Remove the current region from its VPlan, connecting its predecessor to
   /// its entry, and its exiting block to its successor.
   void dissolveToCFGLoop();
+
+  /// Returns the canonical induction recipe of the region.
+  VPCanonicalIVPHIRecipe *getCanonicalIV() {
+    VPBasicBlock *EntryVPBB = getEntryBasicBlock();
+    if (EntryVPBB->empty()) {
+      // VPlan native path.
+      EntryVPBB = cast<VPBasicBlock>(EntryVPBB->getSingleSuccessor());
+    }
+    return cast<VPCanonicalIVPHIRecipe>(&*EntryVPBB->begin());
+  }
 };
 
 /// VPlan models a candidate for vectorization, encoding various decisions take
@@ -4377,16 +4387,6 @@ class VPlan {
   LLVM_DUMP_METHOD void dump() const;
 #endif
 
-  /// Returns the canonical induction recipe of the vector loop.
-  VPCanonicalIVPHIRecipe *getCanonicalIV() {
-    VPBasicBlock *EntryVPBB = getVectorLoopRegion()->getEntryBasicBlock();
-    if (EntryVPBB->empty()) {
-      // VPlan native path.
-      EntryVPBB = cast<VPBasicBlock>(EntryVPBB->getSingleSuccessor());
-    }
-    return cast<VPCanonicalIVPHIRecipe>(&*EntryVPBB->begin());
-  }
-
   VPValue *getSCEVExpansion(const SCEV *S) const {
     return SCEVToExpansion.lookup(S);
   }
diff --git a/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp b/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
index 81deba2932ef8..55ec19281c876 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
@@ -661,9 +661,11 @@ void VPlanTransforms::attachCheckBlock(VPlan &Plan, Value *Cond,
   }
 
   VPIRMetadata VPBranchWeights;
-  auto *Term = VPBuilder(CheckBlockVPBB)
-                   .createNaryOp(VPInstruction::BranchOnCond, {CondVPV},
-                                 Plan.getCanonicalIV()->getDebugLoc());
+  auto *Term =
+      VPBuilder(CheckBlockVPBB)
+          .createNaryOp(
+              VPInstruction::BranchOnCond, {CondVPV},
+              Plan.getVectorLoopRegion()->getCanonicalIV()->getDebugLoc());
   if (AddBranchWeights) {
     MDBuilder MDB(Plan.getContext());
     MDNode *BranchWeights =
@@ -925,8 +927,8 @@ bool VPlanTransforms::handleMaxMinNumReductions(VPlan &Plan) {
     if (auto *DerivedIV = dyn_cast<VPDerivedIVRecipe>(VecV)) {
       if (DerivedIV->getNumUsers() == 1 &&
           DerivedIV->getOperand(1) == &Plan.getVectorTripCount()) {
-        auto *NewSel = Builder.createSelect(AnyNaN, Plan.getCanonicalIV(),
-                                            &Plan.getVectorTripCount());
+        auto *NewSel = Builder.createSelect(
+            AnyNaN, LoopRegion->getCanonicalIV(), &Plan.getVectorTripCount());
         DerivedIV->moveAfter(&*Builder.getInsertPoint());
         DerivedIV->setOperand(1, NewSel);
         continue;
@@ -939,7 +941,8 @@ bool VPlanTransforms::handleMaxMinNumReductions(VPlan &Plan) {
                            "FMaxNum/FMinNum reduction.\n");
       return false;
     }
-    auto *NewSel = Builder.createSelect(AnyNaN, Plan.getCanonicalIV(), VecV);
+    auto *NewSel =
+        Builder.createSelect(AnyNaN, LoopRegion->getCanonicalIV(), VecV);
     ResumeR->setOperand(0, NewSel);
   }
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp b/llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp
index 0c27d535b680e..1d0472df1762e 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp
@@ -168,7 +168,8 @@ void VPPredicator::createHeaderMask(VPBasicBlock *HeaderVPBB, bool FoldTail) {
   // non-phi instructions.
 
   auto &Plan = *HeaderVPBB->getPlan();
-  auto *IV = new VPWidenCanonicalIVRecipe(Plan.getCanonicalIV());
+  auto *IV = new VPWidenCanonicalIVRecipe(
+      Plan.getVectorLoopRegion()->getCanonicalIV());
   Builder.setInsertPoint(HeaderVPBB, HeaderVPBB->getFirstNonPhi());
   Builder.insert(IV);
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index c8a2d84a535d3..ef1492320e1c3 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -501,7 +501,8 @@ static void removeRedundantInductionCasts(VPlan &Plan) {
 /// Try to replace VPWidenCanonicalIVRecipes with a widened canonical IV
 /// recipe, if it exists.
 static void removeRedundantCanonicalIVs(VPlan &Plan) {
-  VPCanonicalIVPHIRecipe *CanonicalIV = Plan.getCanonicalIV();
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  VPCanonicalIVPHIRecipe *CanonicalIV = LoopRegion->getCanonicalIV();
   VPWidenCanonicalIVRecipe *WidenNewIV = nullptr;
   for (VPUser *U : CanonicalIV->users()) {
     WidenNewIV = dyn_cast<VPWidenCanonicalIVRecipe>(U);
@@ -512,7 +513,7 @@ static void removeRedundantCanonicalIVs(VPlan &Plan) {
   if (!WidenNewIV)
     return;
 
-  VPBasicBlock *HeaderVPBB = Plan.getVectorLoopRegion()->getEntryBasicBlock();
+  VPBasicBlock *HeaderVPBB = LoopRegion->getEntryBasicBlock();
   for (VPRecipeBase &Phi : HeaderVPBB->phis()) {
     auto *WidenOriginalIV = dyn_cast<VPWidenIntOrFpInductionRecipe>(&Phi);
 
@@ -582,8 +583,9 @@ createScalarIVSteps(VPlan &Plan, InductionDescriptor::InductionKind Kind,
                     FPMathOperator *FPBinOp, Instruction *TruncI,
                     VPValue *StartV, VPValue *Step, DebugLoc DL,
                     VPBuilder &Builder) {
-  VPBasicBlock *HeaderVPBB = Plan.getVectorLoopRegion()->getEntryBasicBlock();
-  VPCanonicalIVPHIRecipe *CanonicalIV = Plan.getCanonicalIV();
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  VPBasicBlock *HeaderVPBB = LoopRegion->getEntryBasicBlock();
+  VPCanonicalIVPHIRecipe *CanonicalIV = LoopRegion->getCanonicalIV();
   VPSingleDefRecipe *BaseIV = Builder.createDerivedIV(
       Kind, FPBinOp, StartV, CanonicalIV, Step, "offset.idx");
 
@@ -800,8 +802,9 @@ static VPValue *optimizeEarlyExitInductionUser(VPlan &Plan,
     return nullptr;
 
   // Calculate the final index.
-  VPValue *EndValue = Plan.getCanonicalIV();
-  auto CanonicalIVType = Plan.getCanonicalIV()->getScalarType();
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  VPValue *EndValue = LoopRegion->getCanonicalIV();
+  auto CanonicalIVType = LoopRegion->getCanonicalIV()->getScalarType();
   VPBuilder B(cast<VPBasicBlock>(PredVPBB));
 
   DebugLoc DL = cast<VPInstruction>(Op)->getDebugLoc();
@@ -1520,7 +1523,7 @@ static bool isConditionTrueViaVFAndUF(VPValue *Cond, VPlan &Plan,
       return isConditionTrueViaVFAndUF(C, Plan, BestVF, BestUF, SE);
     });
 
-  auto *CanIV = Plan.getCanonicalIV();
+  auto *CanIV = Plan.getVectorLoopRegion()->getCanonicalIV();
   if (!match(Cond, m_SpecificICmp(CmpInst::ICMP_EQ,
                                   m_Specific(CanIV->getBackedgeValue()),
                                   m_Specific(&Plan.getVectorTripCount()))))
@@ -2304,7 +2307,7 @@ static VPActiveLaneMaskPHIRecipe *addVPLaneMaskPhiAndUpdateExitBranch(
     VPlan &Plan, bool DataAndControlFlowWithoutRuntimeCheck) {
   VPRegionBlock *TopRegion = Plan.getVectorLoopRegion();
   VPBasicBlock *EB = TopRegion->getExitingBasicBlock();
-  auto *CanonicalIVPHI = Plan.getCanonicalIV();
+  auto *CanonicalIVPHI = TopRegion->getCanonicalIV();
   VPValue *StartV = CanonicalIVPHI->getStartValue();
 
   auto *CanonicalIVIncrement =
@@ -2343,7 +2346,7 @@ static VPActiveLaneMaskPHIRecipe *addVPLaneMaskPhiAndUpdateExitBranch(
 
   // Create the active lane mask instruction in the VPlan preheader.
   VPValue *ALMMultiplier = Plan.getOrAddLiveIn(
-      ConstantInt::get(Plan.getCanonicalIV()->getScalarType(), 1));
+      ConstantInt::get(TopRegion->getCanonicalIV()->getScalarType(), 1));
   auto *EntryALM = Builder.createNaryOp(VPInstruction::ActiveLaneMask,
                                         {EntryIncrement, TC, ALMMultiplier}, DL,
                                         "active.lane.mask.entry");
@@ -2379,13 +2382,15 @@ static VPActiveLaneMaskPHIRecipe *addVPLaneMaskPhiAndUpdateExitBranch(
 /// TODO: Introduce explicit recipe for header-mask instead of searching
 /// for the header-mask pattern manually.
 static VPSingleDefRecipe *findHeaderMask(VPlan &Plan) {
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
   SmallVector<VPValue *> WideCanonicalIVs;
-  auto *FoundWidenCanonicalIVUser = find_if(Plan.getCanonicalIV()->users(),
-                                            IsaPred<VPWidenCanonicalIVRecipe>);
-  assert(count_if(Plan.getCanonicalIV()->users(),
+  auto *FoundWidenCanonicalIVUser = find_if(
+      LoopRegion->getCanonicalIV()->users(), IsaPred<VPWidenCanonicalIVRecipe>);
+  assert(count_if(LoopRegion->getCanonicalIV()->users(),
                   IsaPred<VPWidenCanonicalIVRecipe>) <= 1 &&
          "Must have at most one VPWideCanonicalIVRecipe");
-  if (FoundWidenCanonicalIVUser != Plan.getCanonicalIV()->users().end()) {
+  if (FoundWidenCanonicalIVUser !=
+      LoopRegion->getCanonicalIV()->users().end()) {
     auto *WideCanonicalIV =
         cast<VPWidenCanonicalIVRecipe>(*FoundWidenCanonicalIVUser);
     WideCanonicalIVs.push_back(WideCanonicalIV);
@@ -2393,7 +2398,7 @@ static VPSingleDefRecipe *findHeaderMask(VPlan &Plan) {
 
   // Also include VPWidenIntOrFpInductionRecipes that represent a widened
   // version of the canonical induction.
-  VPBasicBlock *HeaderVPBB = Plan.getVectorLoopRegion()->getEntryBasicBlock();
+  VPBasicBlock *HeaderVPBB = LoopRegion->getEntryBasicBlock();
   for (VPRecipeBase &Phi : HeaderVPBB->phis()) {
     auto *WidenOriginalIV = dyn_cast<VPWidenIntOrFpInductionRecipe>(&Phi);
     if (WidenOriginalIV && WidenOriginalIV->isCanonical())
@@ -2426,8 +2431,9 @@ void VPlanTransforms::addActiveLaneMask(
          "DataAndControlFlowWithoutRuntimeCheck implies "
          "UseActiveLaneMaskForControlFlow");
 
-  auto *FoundWidenCanonicalIVUser = find_if(Plan.getCanonicalIV()->users(),
-                                            IsaPred<VPWidenCanonicalIVRecipe>);
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  auto *FoundWidenCanonicalIVUser = find_if(
+      LoopRegion->getCanonicalIV()->users(), IsaPred<VPWidenCanonicalIVRecipe>);
   assert(FoundWidenCanonicalIVUser &&
          "Must have widened canonical IV when tail folding!");
   VPSingleDefRecipe *HeaderMask = findHeaderMask(Plan);
@@ -2440,7 +2446,7 @@ void VPlanTransforms::addActiveLaneMask(
   } else {
     VPBuilder B = VPBuilder::getToInsertAfter(WideCanonicalIV);
     VPValue *ALMMultiplier = Plan.getOrAddLiveIn(
-        ConstantInt::get(Plan.getCanonicalIV()->getScalarType(), 1));
+        ConstantInt::get(LoopRegion->getCanonicalIV()->getScalarType(), 1));
     LaneMask =
         B.createNaryOp(VPInstruction::ActiveLaneMask,
                        {WideCanonicalIV, Plan.getTripCount(), ALMMultiplier},
@@ -2550,9 +2556,10 @@ static void transformRecipestoEVLRecipes(VPlan &Plan, VPValue &EVL) {
   });
 
   assert(all_of(Plan.getVFxUF().users(),
-                [&Plan](VPUser *U) {
-                  return match(U, m_c_Add(m_Specific(Plan.getCanonicalIV()),
-                                          m_Specific(&Plan.getVFxUF()))) ||
+                [&LoopRegion, &Plan](VPUser *U) {
+                  return match(U,
+                               m_c_Add(m_Specific(LoopRegion->getCanonicalIV()),
+                                       m_Specific(&Plan.getVFxUF()))) ||
                          isa<VPWidenPointerInductionRecipe>(U);
                 }) &&
          "Only users of VFxUF should be VPWidenPointerInductionRecipe and the "
@@ -2707,9 +2714,10 @@ void VPlanTransforms::addExplicitVectorLength(
     VPlan &Plan, const std::optional<unsigned> &MaxSafeElements) {
   if (Plan.hasScalarVFOnly())
     return;
-  VPBasicBlock *Header = Plan.getVectorLoopRegion()->getEntryBasicBlock();
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  VPBasicBlock *Header = LoopRegion->getEntryBasicBlock();
 
-  auto *CanonicalIVPHI = Plan.getCanonicalIV();
+  auto *CanonicalIVPHI = LoopRegion->getCanonicalIV();
   auto *CanIVTy = CanonicalIVPHI->getScalarType();
   VPValue *StartV = CanonicalIVPHI->getStartValue();
 
@@ -4153,7 +4161,7 @@ void VPlanTransforms::narrowInterleaveGroups(VPlan &Plan, ElementCount VF,
 
   // Adjust induction to reflect that the transformed plan only processes one
   // original iteration.
-  auto *CanIV = Plan.getCanonicalIV();
+  auto *CanIV = VectorLoop->getCanonicalIV();
   auto *Inc = cast<VPInstruction>(CanIV->getBackedgeValue());
   VPBuilder PHBuilder(Plan.getVectorPreheader());
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp b/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
index 5e7f19faebb56..14682d851e765 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
@@ -69,7 +69,8 @@ class UnrollState {
                                 VPBasicBlock::iterator InsertPtForPhi);
 
   VPValue *getConstantVPV(unsigned Part) {
-    Type *CanIVIntTy = Plan.getCanonicalIV()->getScalarType();
+    Type *CanIVIntTy =
+        Plan.getVectorLoopRegion()->getCanonicalIV()->getScalarType();
     return Plan.getOrAddLiveIn(ConstantInt::get(CanIVIntTy, Part));
   }
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
index 66748c534f10b..553731731a1d8 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
@@ -67,8 +67,10 @@ bool vputils::isHeaderMask(const VPValue *V, VPlan &Plan) {
 
   if (match(V, m_ActiveLaneMask(m_VPValue(A), m_VPValue(B), m_One())))
     return B == Plan.getTripCount() &&
-           (match(A, m_ScalarIVSteps(m_Specific(Plan.getCanonicalIV()), m_One(),
-                                     m_Specific(&Plan.getVF()))) ||
+           (match(A,
+                  m_ScalarIVSteps(
+                      m_Specific(Plan.getVectorLoopRegion()->getCanonicalIV()),
+                      m_One(), m_Specific(&Plan.getVF()))) ||
             IsWideCanonicalIV(A));
 
   return match(V, m_ICmp(m_VPValue(A), m_VPValue(B))) && IsWideCanonicalIV(A) &&
@@ -102,7 +104,8 @@ bool vputils::isUniformAcrossVFsAndUFs(VPValue *V) {
     return all_of(R->operands(), isUniformAcrossVFsAndUFs);
   }
 
-  auto *CanonicalIV = R->getParent()->getPlan()->getCanonicalIV();
+  auto *CanonicalIV =
+      R->getParent()->getPlan()->getVectorLoopRegion()->getCanonicalIV();
   // Canonical IV chain is uniform.
   if (V == CanonicalIV || V == CanonicalIV->getBackedgeValue())
     return true;

@llvmbot
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llvmbot commented Oct 11, 2025

@llvm/pr-subscribers-vectorizers

Author: Florian Hahn (fhahn)

Changes

The canonical IV is tied to region blocks; move getCanonicalIV there and update all users.

Full diff: https://github.com/llvm/llvm-project/pull/163020.diff

7 Files Affected:

  • (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+12-11)
  • (modified) llvm/lib/Transforms/Vectorize/VPlan.h (+10-10)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp (+9-6)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp (+2-1)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp (+31-23)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp (+2-1)
  • (modified) llvm/lib/Transforms/Vectorize/VPlanUtils.cpp (+6-3)
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index e62d57e6920b7..7a041fda07321 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8242,12 +8242,12 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(
   // count is >= increment and a multiple of the increment.
   bool HasNUW = !IVUpdateMayOverflow || Style == TailFoldingStyle::None;
   if (!HasNUW) {
-    auto *IVInc = Plan->getVectorLoopRegion()
-                      ->getExitingBasicBlock()
-                      ->getTerminator()
-                      ->getOperand(0);
-    assert(match(IVInc, m_VPInstruction<Instruction::Add>(
-                            m_Specific(Plan->getCanonicalIV()), m_VPValue())) &&
+    VPRegionBlock *LoopRegion = Plan->getVectorLoopRegion();
+    auto *IVInc =
+        LoopRegion->getExitingBasicBlock()->getTerminator()->getOperand(0);
+    assert(match(IVInc,
+                 m_VPInstruction<Instruction::Add>(
+                     m_Specific(LoopRegion->getCanonicalIV()), m_VPValue())) &&
            "Did not find the canonical IV increment");
     cast<VPRecipeWithIRFlags>(IVInc)->dropPoisonGeneratingFlags();
   }
@@ -8377,8 +8377,8 @@ VPlanPtr LoopVectorizationPlanner::tryToBuildVPlanWithVPRecipes(
   for (VPValue *Old : Old2New.keys())
     Old->getDefiningRecipe()->eraseFromParent();
 
-  assert(isa<VPRegionBlock>(Plan->getVectorLoopRegion()) &&
-         !Plan->getVectorLoopRegion()->getEntryBasicBlock()->empty() &&
+  assert(isa<VPRegionBlock>(LoopRegion) &&
+         !LoopRegion->getEntryBasicBlock()->empty() &&
          "entry block must be set to a VPRegionBlock having a non-empty entry "
          "VPBasicBlock");
 
@@ -9320,8 +9320,9 @@ static void preparePlanForMainVectorLoop(VPlan &MainPlan, VPlan &EpiPlan) {
   if (ResumePhiIter == MainScalarPH->phis().end()) {
     VPBuilder ScalarPHBuilder(MainScalarPH, MainScalarPH->begin());
     ResumePhi = ScalarPHBuilder.createScalarPhi(
-        {VectorTC, MainPlan.getCanonicalIV()->getStartValue()}, {},
-        "vec.epilog.resume.val");
+        {VectorTC,
+         MainPlan.getVectorLoopRegion()->getCanonicalIV()->getStartValue()},
+        {}, "vec.epilog.resume.val");
   } else {
     ResumePhi = cast<VPPhi>(&*ResumePhiIter);
     if (MainScalarPH->begin() == MainScalarPH->end())
@@ -9350,7 +9351,7 @@ static SmallVector<Instruction *> preparePlanForEpilogueVectorLoop(
 
   // Ensure that the start values for all header phi recipes are updated before
   // vectorizing the epilogue loop.
-  VPCanonicalIVPHIRecipe *IV = Plan.getCanonicalIV();
+  VPCanonicalIVPHIRecipe *IV = VectorLoop->getCanonicalIV();
   // When vectorizing the epilogue loop, the canonical induction start
   // value needs to be changed from zero to the value after the main
   // vector loop. Find the resume value created during execution of the main
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index fb696bea671af..8db626fe9bf58 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -4066,6 +4066,16 @@ class LLVM_ABI_FOR_TEST VPRegionBlock : public VPBlockBase {
   /// Remove the current region from its VPlan, connecting its predecessor to
   /// its entry, and its exiting block to its successor.
   void dissolveToCFGLoop();
+
+  /// Returns the canonical induction recipe of the region.
+  VPCanonicalIVPHIRecipe *getCanonicalIV() {
+    VPBasicBlock *EntryVPBB = getEntryBasicBlock();
+    if (EntryVPBB->empty()) {
+      // VPlan native path.
+      EntryVPBB = cast<VPBasicBlock>(EntryVPBB->getSingleSuccessor());
+    }
+    return cast<VPCanonicalIVPHIRecipe>(&*EntryVPBB->begin());
+  }
 };
 
 /// VPlan models a candidate for vectorization, encoding various decisions take
@@ -4377,16 +4387,6 @@ class VPlan {
   LLVM_DUMP_METHOD void dump() const;
 #endif
 
-  /// Returns the canonical induction recipe of the vector loop.
-  VPCanonicalIVPHIRecipe *getCanonicalIV() {
-    VPBasicBlock *EntryVPBB = getVectorLoopRegion()->getEntryBasicBlock();
-    if (EntryVPBB->empty()) {
-      // VPlan native path.
-      EntryVPBB = cast<VPBasicBlock>(EntryVPBB->getSingleSuccessor());
-    }
-    return cast<VPCanonicalIVPHIRecipe>(&*EntryVPBB->begin());
-  }
-
   VPValue *getSCEVExpansion(const SCEV *S) const {
     return SCEVToExpansion.lookup(S);
   }
diff --git a/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp b/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
index 81deba2932ef8..55ec19281c876 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanConstruction.cpp
@@ -661,9 +661,11 @@ void VPlanTransforms::attachCheckBlock(VPlan &Plan, Value *Cond,
   }
 
   VPIRMetadata VPBranchWeights;
-  auto *Term = VPBuilder(CheckBlockVPBB)
-                   .createNaryOp(VPInstruction::BranchOnCond, {CondVPV},
-                                 Plan.getCanonicalIV()->getDebugLoc());
+  auto *Term =
+      VPBuilder(CheckBlockVPBB)
+          .createNaryOp(
+              VPInstruction::BranchOnCond, {CondVPV},
+              Plan.getVectorLoopRegion()->getCanonicalIV()->getDebugLoc());
   if (AddBranchWeights) {
     MDBuilder MDB(Plan.getContext());
     MDNode *BranchWeights =
@@ -925,8 +927,8 @@ bool VPlanTransforms::handleMaxMinNumReductions(VPlan &Plan) {
     if (auto *DerivedIV = dyn_cast<VPDerivedIVRecipe>(VecV)) {
       if (DerivedIV->getNumUsers() == 1 &&
           DerivedIV->getOperand(1) == &Plan.getVectorTripCount()) {
-        auto *NewSel = Builder.createSelect(AnyNaN, Plan.getCanonicalIV(),
-                                            &Plan.getVectorTripCount());
+        auto *NewSel = Builder.createSelect(
+            AnyNaN, LoopRegion->getCanonicalIV(), &Plan.getVectorTripCount());
         DerivedIV->moveAfter(&*Builder.getInsertPoint());
         DerivedIV->setOperand(1, NewSel);
         continue;
@@ -939,7 +941,8 @@ bool VPlanTransforms::handleMaxMinNumReductions(VPlan &Plan) {
                            "FMaxNum/FMinNum reduction.\n");
       return false;
     }
-    auto *NewSel = Builder.createSelect(AnyNaN, Plan.getCanonicalIV(), VecV);
+    auto *NewSel =
+        Builder.createSelect(AnyNaN, LoopRegion->getCanonicalIV(), VecV);
     ResumeR->setOperand(0, NewSel);
   }
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp b/llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp
index 0c27d535b680e..1d0472df1762e 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanPredicator.cpp
@@ -168,7 +168,8 @@ void VPPredicator::createHeaderMask(VPBasicBlock *HeaderVPBB, bool FoldTail) {
   // non-phi instructions.
 
   auto &Plan = *HeaderVPBB->getPlan();
-  auto *IV = new VPWidenCanonicalIVRecipe(Plan.getCanonicalIV());
+  auto *IV = new VPWidenCanonicalIVRecipe(
+      Plan.getVectorLoopRegion()->getCanonicalIV());
   Builder.setInsertPoint(HeaderVPBB, HeaderVPBB->getFirstNonPhi());
   Builder.insert(IV);
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index c8a2d84a535d3..ef1492320e1c3 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -501,7 +501,8 @@ static void removeRedundantInductionCasts(VPlan &Plan) {
 /// Try to replace VPWidenCanonicalIVRecipes with a widened canonical IV
 /// recipe, if it exists.
 static void removeRedundantCanonicalIVs(VPlan &Plan) {
-  VPCanonicalIVPHIRecipe *CanonicalIV = Plan.getCanonicalIV();
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  VPCanonicalIVPHIRecipe *CanonicalIV = LoopRegion->getCanonicalIV();
   VPWidenCanonicalIVRecipe *WidenNewIV = nullptr;
   for (VPUser *U : CanonicalIV->users()) {
     WidenNewIV = dyn_cast<VPWidenCanonicalIVRecipe>(U);
@@ -512,7 +513,7 @@ static void removeRedundantCanonicalIVs(VPlan &Plan) {
   if (!WidenNewIV)
     return;
 
-  VPBasicBlock *HeaderVPBB = Plan.getVectorLoopRegion()->getEntryBasicBlock();
+  VPBasicBlock *HeaderVPBB = LoopRegion->getEntryBasicBlock();
   for (VPRecipeBase &Phi : HeaderVPBB->phis()) {
     auto *WidenOriginalIV = dyn_cast<VPWidenIntOrFpInductionRecipe>(&Phi);
 
@@ -582,8 +583,9 @@ createScalarIVSteps(VPlan &Plan, InductionDescriptor::InductionKind Kind,
                     FPMathOperator *FPBinOp, Instruction *TruncI,
                     VPValue *StartV, VPValue *Step, DebugLoc DL,
                     VPBuilder &Builder) {
-  VPBasicBlock *HeaderVPBB = Plan.getVectorLoopRegion()->getEntryBasicBlock();
-  VPCanonicalIVPHIRecipe *CanonicalIV = Plan.getCanonicalIV();
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  VPBasicBlock *HeaderVPBB = LoopRegion->getEntryBasicBlock();
+  VPCanonicalIVPHIRecipe *CanonicalIV = LoopRegion->getCanonicalIV();
   VPSingleDefRecipe *BaseIV = Builder.createDerivedIV(
       Kind, FPBinOp, StartV, CanonicalIV, Step, "offset.idx");
 
@@ -800,8 +802,9 @@ static VPValue *optimizeEarlyExitInductionUser(VPlan &Plan,
     return nullptr;
 
   // Calculate the final index.
-  VPValue *EndValue = Plan.getCanonicalIV();
-  auto CanonicalIVType = Plan.getCanonicalIV()->getScalarType();
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  VPValue *EndValue = LoopRegion->getCanonicalIV();
+  auto CanonicalIVType = LoopRegion->getCanonicalIV()->getScalarType();
   VPBuilder B(cast<VPBasicBlock>(PredVPBB));
 
   DebugLoc DL = cast<VPInstruction>(Op)->getDebugLoc();
@@ -1520,7 +1523,7 @@ static bool isConditionTrueViaVFAndUF(VPValue *Cond, VPlan &Plan,
       return isConditionTrueViaVFAndUF(C, Plan, BestVF, BestUF, SE);
     });
 
-  auto *CanIV = Plan.getCanonicalIV();
+  auto *CanIV = Plan.getVectorLoopRegion()->getCanonicalIV();
   if (!match(Cond, m_SpecificICmp(CmpInst::ICMP_EQ,
                                   m_Specific(CanIV->getBackedgeValue()),
                                   m_Specific(&Plan.getVectorTripCount()))))
@@ -2304,7 +2307,7 @@ static VPActiveLaneMaskPHIRecipe *addVPLaneMaskPhiAndUpdateExitBranch(
     VPlan &Plan, bool DataAndControlFlowWithoutRuntimeCheck) {
   VPRegionBlock *TopRegion = Plan.getVectorLoopRegion();
   VPBasicBlock *EB = TopRegion->getExitingBasicBlock();
-  auto *CanonicalIVPHI = Plan.getCanonicalIV();
+  auto *CanonicalIVPHI = TopRegion->getCanonicalIV();
   VPValue *StartV = CanonicalIVPHI->getStartValue();
 
   auto *CanonicalIVIncrement =
@@ -2343,7 +2346,7 @@ static VPActiveLaneMaskPHIRecipe *addVPLaneMaskPhiAndUpdateExitBranch(
 
   // Create the active lane mask instruction in the VPlan preheader.
   VPValue *ALMMultiplier = Plan.getOrAddLiveIn(
-      ConstantInt::get(Plan.getCanonicalIV()->getScalarType(), 1));
+      ConstantInt::get(TopRegion->getCanonicalIV()->getScalarType(), 1));
   auto *EntryALM = Builder.createNaryOp(VPInstruction::ActiveLaneMask,
                                         {EntryIncrement, TC, ALMMultiplier}, DL,
                                         "active.lane.mask.entry");
@@ -2379,13 +2382,15 @@ static VPActiveLaneMaskPHIRecipe *addVPLaneMaskPhiAndUpdateExitBranch(
 /// TODO: Introduce explicit recipe for header-mask instead of searching
 /// for the header-mask pattern manually.
 static VPSingleDefRecipe *findHeaderMask(VPlan &Plan) {
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
   SmallVector<VPValue *> WideCanonicalIVs;
-  auto *FoundWidenCanonicalIVUser = find_if(Plan.getCanonicalIV()->users(),
-                                            IsaPred<VPWidenCanonicalIVRecipe>);
-  assert(count_if(Plan.getCanonicalIV()->users(),
+  auto *FoundWidenCanonicalIVUser = find_if(
+      LoopRegion->getCanonicalIV()->users(), IsaPred<VPWidenCanonicalIVRecipe>);
+  assert(count_if(LoopRegion->getCanonicalIV()->users(),
                   IsaPred<VPWidenCanonicalIVRecipe>) <= 1 &&
          "Must have at most one VPWideCanonicalIVRecipe");
-  if (FoundWidenCanonicalIVUser != Plan.getCanonicalIV()->users().end()) {
+  if (FoundWidenCanonicalIVUser !=
+      LoopRegion->getCanonicalIV()->users().end()) {
     auto *WideCanonicalIV =
         cast<VPWidenCanonicalIVRecipe>(*FoundWidenCanonicalIVUser);
     WideCanonicalIVs.push_back(WideCanonicalIV);
@@ -2393,7 +2398,7 @@ static VPSingleDefRecipe *findHeaderMask(VPlan &Plan) {
 
   // Also include VPWidenIntOrFpInductionRecipes that represent a widened
   // version of the canonical induction.
-  VPBasicBlock *HeaderVPBB = Plan.getVectorLoopRegion()->getEntryBasicBlock();
+  VPBasicBlock *HeaderVPBB = LoopRegion->getEntryBasicBlock();
   for (VPRecipeBase &Phi : HeaderVPBB->phis()) {
     auto *WidenOriginalIV = dyn_cast<VPWidenIntOrFpInductionRecipe>(&Phi);
     if (WidenOriginalIV && WidenOriginalIV->isCanonical())
@@ -2426,8 +2431,9 @@ void VPlanTransforms::addActiveLaneMask(
          "DataAndControlFlowWithoutRuntimeCheck implies "
          "UseActiveLaneMaskForControlFlow");
 
-  auto *FoundWidenCanonicalIVUser = find_if(Plan.getCanonicalIV()->users(),
-                                            IsaPred<VPWidenCanonicalIVRecipe>);
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  auto *FoundWidenCanonicalIVUser = find_if(
+      LoopRegion->getCanonicalIV()->users(), IsaPred<VPWidenCanonicalIVRecipe>);
   assert(FoundWidenCanonicalIVUser &&
          "Must have widened canonical IV when tail folding!");
   VPSingleDefRecipe *HeaderMask = findHeaderMask(Plan);
@@ -2440,7 +2446,7 @@ void VPlanTransforms::addActiveLaneMask(
   } else {
     VPBuilder B = VPBuilder::getToInsertAfter(WideCanonicalIV);
     VPValue *ALMMultiplier = Plan.getOrAddLiveIn(
-        ConstantInt::get(Plan.getCanonicalIV()->getScalarType(), 1));
+        ConstantInt::get(LoopRegion->getCanonicalIV()->getScalarType(), 1));
     LaneMask =
         B.createNaryOp(VPInstruction::ActiveLaneMask,
                        {WideCanonicalIV, Plan.getTripCount(), ALMMultiplier},
@@ -2550,9 +2556,10 @@ static void transformRecipestoEVLRecipes(VPlan &Plan, VPValue &EVL) {
   });
 
   assert(all_of(Plan.getVFxUF().users(),
-                [&Plan](VPUser *U) {
-                  return match(U, m_c_Add(m_Specific(Plan.getCanonicalIV()),
-                                          m_Specific(&Plan.getVFxUF()))) ||
+                [&LoopRegion, &Plan](VPUser *U) {
+                  return match(U,
+                               m_c_Add(m_Specific(LoopRegion->getCanonicalIV()),
+                                       m_Specific(&Plan.getVFxUF()))) ||
                          isa<VPWidenPointerInductionRecipe>(U);
                 }) &&
          "Only users of VFxUF should be VPWidenPointerInductionRecipe and the "
@@ -2707,9 +2714,10 @@ void VPlanTransforms::addExplicitVectorLength(
     VPlan &Plan, const std::optional<unsigned> &MaxSafeElements) {
   if (Plan.hasScalarVFOnly())
     return;
-  VPBasicBlock *Header = Plan.getVectorLoopRegion()->getEntryBasicBlock();
+  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
+  VPBasicBlock *Header = LoopRegion->getEntryBasicBlock();
 
-  auto *CanonicalIVPHI = Plan.getCanonicalIV();
+  auto *CanonicalIVPHI = LoopRegion->getCanonicalIV();
   auto *CanIVTy = CanonicalIVPHI->getScalarType();
   VPValue *StartV = CanonicalIVPHI->getStartValue();
 
@@ -4153,7 +4161,7 @@ void VPlanTransforms::narrowInterleaveGroups(VPlan &Plan, ElementCount VF,
 
   // Adjust induction to reflect that the transformed plan only processes one
   // original iteration.
-  auto *CanIV = Plan.getCanonicalIV();
+  auto *CanIV = VectorLoop->getCanonicalIV();
   auto *Inc = cast<VPInstruction>(CanIV->getBackedgeValue());
   VPBuilder PHBuilder(Plan.getVectorPreheader());
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp b/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
index 5e7f19faebb56..14682d851e765 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
@@ -69,7 +69,8 @@ class UnrollState {
                                 VPBasicBlock::iterator InsertPtForPhi);
 
   VPValue *getConstantVPV(unsigned Part) {
-    Type *CanIVIntTy = Plan.getCanonicalIV()->getScalarType();
+    Type *CanIVIntTy =
+        Plan.getVectorLoopRegion()->getCanonicalIV()->getScalarType();
     return Plan.getOrAddLiveIn(ConstantInt::get(CanIVIntTy, Part));
   }
 
diff --git a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
index 66748c534f10b..553731731a1d8 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanUtils.cpp
@@ -67,8 +67,10 @@ bool vputils::isHeaderMask(const VPValue *V, VPlan &Plan) {
 
   if (match(V, m_ActiveLaneMask(m_VPValue(A), m_VPValue(B), m_One())))
     return B == Plan.getTripCount() &&
-           (match(A, m_ScalarIVSteps(m_Specific(Plan.getCanonicalIV()), m_One(),
-                                     m_Specific(&Plan.getVF()))) ||
+           (match(A,
+                  m_ScalarIVSteps(
+                      m_Specific(Plan.getVectorLoopRegion()->getCanonicalIV()),
+                      m_One(), m_Specific(&Plan.getVF()))) ||
             IsWideCanonicalIV(A));
 
   return match(V, m_ICmp(m_VPValue(A), m_VPValue(B))) && IsWideCanonicalIV(A) &&
@@ -102,7 +104,8 @@ bool vputils::isUniformAcrossVFsAndUFs(VPValue *V) {
     return all_of(R->operands(), isUniformAcrossVFsAndUFs);
   }
 
-  auto *CanonicalIV = R->getParent()->getPlan()->getCanonicalIV();
+  auto *CanonicalIV =
+      R->getParent()->getPlan()->getVectorLoopRegion()->getCanonicalIV();
   // Canonical IV chain is uniform.
   if (V == CanonicalIV || V == CanonicalIV->getBackedgeValue())
     return true;

@fhahn fhahn mentioned this pull request Oct 11, 2025
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@fhahn fhahn force-pushed the vplan-getcanonicaliv-region branch from 56853f5 to f8b7eff Compare October 12, 2025 07:35
@fhahn
[VPlan] Move getCanonicalIV to VPRegionBlock (NFC).
96263b3 
The canonical IV is tied to region blocks; move getCanonicalIV there and
update all users.
ayalz
ayalz approved these changes Oct 12, 2025
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This LGTM, raises various suggestions.

llvm/lib/Transforms/Vectorize/VPlan.h Outdated
VPCanonicalIVPHIRecipe *getCanonicalIV() {
VPBasicBlock *EntryVPBB = getEntryBasicBlock();
if (EntryVPBB->empty()) {
// VPlan native path.
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TODO to resolve this discrepancy?

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Added thanks

llvm/lib/Transforms/Vectorize/VPlan.h

/// Remove the current region from its VPlan, connecting its predecessor to
/// its entry, and its exiting block to its successor.
void dissolveToCFGLoop();
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Should dissolveToCFGLoop() also call getCanonicalIV(), possibly asserting that it resides in the-header/its-front/the-region?

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Currently getCanonicalIV assumes that the region must have a canonical IV, which may not be the case at the moment (e.g. the inner loop region when vectorizing the outer loop does not have a canonical IV at the moment).

llvm/lib/Transforms/Vectorize/VPlan.h
/// Remove the current region from its VPlan, connecting its predecessor to
/// its entry, and its exiting block to its successor.
void dissolveToCFGLoop();

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Should VPWidenIntOrFpInductionRecipe::isCanonical() also call getCanonicalIV() instead of checking first recipe of header directly?

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Updated, thanks

llvm/lib/Transforms/Vectorize/VPlan.h
/// its entry, and its exiting block to its successor.
void dissolveToCFGLoop();

/// Returns the canonical induction recipe of the region.
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Should VPlanVerifier::verify() (continue to) avoid calling getCanonicalIV() as it would assert rather than return false in case of failure?

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Yep.

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp Outdated
Comment on lines 806 to 807
VPValue *EndValue = LoopRegion->getCanonicalIV();
auto CanonicalIVType = LoopRegion->getCanonicalIV()->getScalarType();
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Independent. resolving the repeated invocations of getCanonicalIV():

Suggested change
VPValue *EndValue = LoopRegion->getCanonicalIV();
auto CanonicalIVType = LoopRegion->getCanonicalIV()->getScalarType();
auto *CanonicalIV = LoopRegion->getCanonicalIV();
auto CanonicalIVType = CanonicalIV->getScalarType();
VPValue *EndValue = CanonicalIV;

or better define EndValue below using
VPValue *EndValue = B.createNaryOp(Instruction::Add, {CanonicalIV, FirstActiveLane}, DL);

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Done thanks

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

/// Try to replace VPWidenCanonicalIVRecipes with a widened canonical IV
/// recipe, if it exists.
static void removeRedundantCanonicalIVs(VPlan &Plan) {
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Independent: shorten name or extend implementation to match it

Suggested change
static void removeRedundantCanonicalIVs(VPlan &Plan) {
static void removeRedundantCanonicalIV(VPlan &Plan) {

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
VPBasicBlock *HeaderVPBB = LoopRegion->getEntryBasicBlock();
for (VPRecipeBase &Phi : HeaderVPBB->phis()) {
auto *WidenOriginalIV = dyn_cast<VPWidenIntOrFpInductionRecipe>(&Phi);

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Independent: if "all users of WidenNewIV demand the first lane only" below - then why is it widened? Holds to recipes generating vectors in general when only their first lane is needed.

llvm/lib/Transforms/Vectorize/VPlanUtils.cpp Outdated

auto *CanonicalIV = R->getParent()->getPlan()->getCanonicalIV();
auto *CanonicalIV =
R->getParent()->getPlan()->getVectorLoopRegion()->getCanonicalIV();
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Suggested change
R->getParent()->getPlan()->getVectorLoopRegion()->getCanonicalIV();
R->getParent()->getEnclosingLoopRegion()->getCanonicalIV();

?

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done thanks

llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
Comment on lines +72 to +73
Type *CanIVIntTy =
Plan.getVectorLoopRegion()->getCanonicalIV()->getScalarType();
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Independent: better have TypeInfo supply CanIVIntTy?

llvm/lib/Transforms/Vectorize/VPlanUnroll.cpp
void unrollWidenInductionByUF(VPWidenInductionRecipe *IV,
VPBasicBlock::iterator InsertPtForPhi);

VPValue *getConstantVPV(unsigned Part) {
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Independent:

Suggested change
VPValue *getConstantVPV(unsigned Part) {
VPValue *getConstantIntVPV(unsigned Part) {

@fhahn fhahn force-pushed the vplan-getcanonicaliv-region branch from f8b7eff to 96263b3 Compare October 12, 2025 09:41
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@ayalz ayalz ayalz approved these changes

@rengolin rengolin Awaiting requested review from rengolin

@aniragil aniragil Awaiting requested review from aniragil

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