[PATCH] D109679: [LV][NFC] Optimize out an extra call to isMoreProfitable

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ebrevnov created this revision.
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Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D109679

Files:
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp


Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1915,7 +1915,7 @@
   SmallPtrSet<Type *, 16> ElementTypesInLoop;
 
   /// Profitable vector factors.
-  SmallVector<VectorizationFactor, 8> ProfitableVFs;
+  SmallVector<VectorizationFactor, 8> CachedVFs;
 
   /// Cached cost of one scalar iteraton;
   VectorizationFactor ScalarVF = {ElementCount::getFixed(1),
@@ -6108,9 +6108,9 @@
       continue;
     }
 
-    // If profitable add it to ProfitableVF list.
-    if (isMoreProfitable(Candidate, getScalarVF()))
-      ProfitableVFs.push_back(Candidate);
+    // Cache calculated cost of the candidate since it will be needed again
+    // during epilogue vectorization cost modeling.
+    CachedVFs.push_back(Candidate);
 
     if (isMoreProfitable(Candidate, ChosenFactor))
       ChosenFactor = Candidate;
@@ -6250,7 +6250,7 @@
 VectorizationFactor
 LoopVectorizationCostModel::selectEpilogueVectorizationFactor(
     const ElementCount MainLoopVF, const LoopVectorizationPlanner &LVP) {
-  VectorizationFactor Result = VectorizationFactor::Disabled();
+  VectorizationFactor Result = getScalarVF();
   if (!EnableEpilogueVectorization) {
     LLVM_DEBUG(dbgs() << "LEV: Epilogue vectorization is disabled.\n";);
     return Result;
@@ -6305,12 +6305,14 @@
   if (!isEpilogueVectorizationProfitable(MainLoopVF))
     return Result;
 
-  for (auto &NextVF : ProfitableVFs)
+  for (auto &NextVF : CachedVFs) {
+    if (NextVF.Width.isScalar())
+      continue;
     if (ElementCount::isKnownLT(NextVF.Width, MainLoopVF) &&
-        (Result.Width.getFixedValue() == 1 ||
-         isMoreProfitable(NextVF, Result)) &&
+        isMoreProfitable(NextVF, Result) &&
         LVP.hasPlanWithVFs({MainLoopVF, NextVF.Width}))
       Result = NextVF;
+  }
 
   if (Result != VectorizationFactor::Disabled())
     LLVM_DEBUG(dbgs() << "LEV: Vectorizing epilogue loop with VF = "


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