[llvm] a84064b - [LV] Add createTripCountSCEV helper (NFC).

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2022-12-21T22:02:31Z
New Revision: a84064bcda1a737658d33e96ca58516d01af70a6

URL: https://github.com/llvm/llvm-project/commit/a84064bcda1a737658d33e96ca58516d01af70a6
DIFF: https://github.com/llvm/llvm-project/commit/a84064bcda1a737658d33e96ca58516d01af70a6.diff

LOG: [LV] Add createTripCountSCEV helper (NFC).

Split off helper function in preparation for D135017.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    llvm/lib/Transforms/Vectorize/VPlan.h

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 2fe899a429be7..334e05d0814f6 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -961,6 +961,27 @@ Value *getRuntimeVF(IRBuilderBase &B, Type *Ty, ElementCount VF) {
   return VF.isScalable() ? B.CreateVScale(EC) : EC;
 }
 
+const SCEV *createTripCountSCEV(Type *IdxTy, PredicatedScalarEvolution &PSE) {
+  const SCEV *BackedgeTakenCount = PSE.getBackedgeTakenCount();
+  assert(!isa<SCEVCouldNotCompute>(BackedgeTakenCount) && "Invalid loop count");
+
+  ScalarEvolution &SE = *PSE.getSE();
+
+  // The exit count might have the type of i64 while the phi is i32. This can
+  // happen if we have an induction variable that is sign extended before the
+  // compare. The only way that we get a backedge taken count is that the
+  // induction variable was signed and as such will not overflow. In such a case
+  // truncation is legal.
+  if (SE.getTypeSizeInBits(BackedgeTakenCount->getType()) >
+      IdxTy->getPrimitiveSizeInBits())
+    BackedgeTakenCount = SE.getTruncateOrNoop(BackedgeTakenCount, IdxTy);
+  BackedgeTakenCount = SE.getNoopOrZeroExtend(BackedgeTakenCount, IdxTy);
+
+  // Get the total trip count from the count by adding 1.
+  return SE.getAddExpr(BackedgeTakenCount,
+                       SE.getOne(BackedgeTakenCount->getType()));
+}
+
 static Value *getRuntimeVFAsFloat(IRBuilderBase &B, Type *FTy,
                                   ElementCount VF) {
   assert(FTy->isFloatingPointTy() && "Expected floating point type!");
@@ -2830,33 +2851,15 @@ Value *InnerLoopVectorizer::getOrCreateTripCount(BasicBlock *InsertBlock) {
   assert(InsertBlock);
   IRBuilder<> Builder(InsertBlock->getTerminator());
   // Find the loop boundaries.
-  ScalarEvolution *SE = PSE.getSE();
-  const SCEV *BackedgeTakenCount = PSE.getBackedgeTakenCount();
-  assert(!isa<SCEVCouldNotCompute>(BackedgeTakenCount) &&
-         "Invalid loop count");
-
   Type *IdxTy = Legal->getWidestInductionType();
   assert(IdxTy && "No type for induction");
-
-  // The exit count might have the type of i64 while the phi is i32. This can
-  // happen if we have an induction variable that is sign extended before the
-  // compare. The only way that we get a backedge taken count is that the
-  // induction variable was signed and as such will not overflow. In such a case
-  // truncation is legal.
-  if (SE->getTypeSizeInBits(BackedgeTakenCount->getType()) >
-      IdxTy->getPrimitiveSizeInBits())
-    BackedgeTakenCount = SE->getTruncateOrNoop(BackedgeTakenCount, IdxTy);
-  BackedgeTakenCount = SE->getNoopOrZeroExtend(BackedgeTakenCount, IdxTy);
-
-  // Get the total trip count from the count by adding 1.
-  const SCEV *ExitCount = SE->getAddExpr(
-      BackedgeTakenCount, SE->getOne(BackedgeTakenCount->getType()));
+  const SCEV *ExitCount = createTripCountSCEV(IdxTy, PSE);
 
   const DataLayout &DL = InsertBlock->getModule()->getDataLayout();
 
   // Expand the trip count and place the new instructions in the preheader.
   // Notice that the pre-header does not change, only the loop body.
-  SCEVExpander Exp(*SE, DL, "induction");
+  SCEVExpander Exp(*PSE.getSE(), DL, "induction");
 
   // Count holds the overall loop count (N).
   TripCount = Exp.expandCodeFor(ExitCount, ExitCount->getType(),

diff  --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index 8370a16df205f..5c7f7291e38c2 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -54,14 +54,17 @@ class InductionDescriptor;
 class InnerLoopVectorizer;
 class IRBuilderBase;
 class LoopInfo;
+class PredicateScalarEvolution;
 class raw_ostream;
 class RecurrenceDescriptor;
-class Value;
+class SCEV;
+class Type;
 class VPBasicBlock;
 class VPRegionBlock;
 class VPlan;
 class VPReplicateRecipe;
 class VPlanSlp;
+class Value;
 
 namespace Intrinsic {
 typedef unsigned ID;
@@ -76,6 +79,8 @@ Value *getRuntimeVF(IRBuilderBase &B, Type *Ty, ElementCount VF);
 Value *createStepForVF(IRBuilderBase &B, Type *Ty, ElementCount VF,
                        int64_t Step);
 
+const SCEV *createTripCountSCEV(Type *IdxTy, PredicatedScalarEvolution &PSE);
+
 /// A range of powers-of-2 vectorization factors with fixed start and
 /// adjustable end. The range includes start and excludes end, e.g.,:
 /// [1, 9) = {1, 2, 4, 8}