[PATCH] D147891: [VPlan] Check VPValue step in isCanonical (NFCI).

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: Ayal, gilr, rengolin.
Herald added subscribers: StephenFan, tschuett, psnobl, rogfer01, bollu, hiraditya.
Herald added a project: All.
fhahn requested review of this revision.
Herald added subscribers: pcwang-thead, vkmr.
Herald added a project: LLVM.

Update the isCanonical() implementations to check the VPValue step
operand instead of the step in the induction descriptor.

At the moment this is NFC, but it enables further optimizations if the
step is replaced by a constant in D147783 <https://reviews.llvm.org/D147783>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147891

Files:
  llvm/lib/Transforms/Vectorize/VPlan.h
  llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
  llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp


Index: llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -520,7 +520,7 @@
     VPValue *Step =
         vputils::getOrCreateVPValueForSCEVExpr(Plan, ID.getStep(), SE);
     VPValue *BaseIV = CanonicalIV;
-    if (!CanonicalIV->isCanonical(ID, ResultTy)) {
+    if (!CanonicalIV->isCanonical(ID, Step, ResultTy)) {
       BaseIV = new VPDerivedIVRecipe(ID, WideIV->getStartValue(), CanonicalIV,
                                      Step, ResultTy);
       HeaderVPBB->insert(BaseIV->getDefiningRecipe(), IP);
Index: llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -736,7 +736,9 @@
 
 bool VPWidenIntOrFpInductionRecipe::isCanonical() const {
   auto *StartC = dyn_cast<ConstantInt>(getStartValue()->getLiveInIRValue());
-  auto *StepC = dyn_cast<SCEVConstant>(getInductionDescriptor().getStep());
+  if (getStepValue()->getDefiningRecipe())
+    return false;
+  auto *StepC = dyn_cast<ConstantInt>(getStepValue()->getLiveInIRValue());
   return StartC && StartC->isZero() && StepC && StepC->isOne();
 }
 
@@ -1092,7 +1094,7 @@
 #endif
 
 bool VPCanonicalIVPHIRecipe::isCanonical(const InductionDescriptor &ID,
-                                         Type *Ty) const {
+                                         VPValue *Step, Type *Ty) const {
   if (Ty != getScalarType())
     return false;
   // The start value of ID must match the start value of this canonical
@@ -1100,11 +1102,15 @@
   if (getStartValue()->getLiveInIRValue() != ID.getStartValue())
     return false;
 
-  ConstantInt *Step = ID.getConstIntStepValue();
+  // If the step is defined by a recipe, it is not a ConstantInt.
+  if (Step->getDefiningRecipe())
+    return false;
+
+  ConstantInt *StepC = dyn_cast<ConstantInt>(Step->getLiveInIRValue());
   // ID must also be incremented by one. IK_IntInduction always increment the
   // induction by Step, but the binary op may not be set.
-  return ID.getKind() == InductionDescriptor::IK_IntInduction && Step &&
-         Step->isOne();
+  return ID.getKind() == InductionDescriptor::IK_IntInduction && StepC &&
+         StepC->isOne();
 }
 
 bool VPWidenPointerInductionRecipe::onlyScalarsGenerated(ElementCount VF) {
Index: llvm/lib/Transforms/Vectorize/VPlan.h
===================================================================
--- llvm/lib/Transforms/Vectorize/VPlan.h
+++ llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1845,7 +1845,8 @@
 
   /// Check if the induction described by \p ID is canonical, i.e.  has the same
   /// start, step (of 1), and type as the canonical IV.
-  bool isCanonical(const InductionDescriptor &ID, Type *Ty) const;
+  bool isCanonical(const InductionDescriptor &ID, VPValue *Step,
+                   Type *Ty) const;
 };
 
 /// A recipe for generating the active lane mask for the vector loop that is


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