[llvm] c63b0f4 - [NFC][LoopVectorize] Make the createStepForVF interface more caller-friendly

[David Sherwood via llvm-commits]

Author: David Sherwood
Date: 2021-11-08T15:14:14Z
New Revision: c63b0f471ba91382eb9f888b20ef77fe178c2916

URL: https://github.com/llvm/llvm-project/commit/c63b0f471ba91382eb9f888b20ef77fe178c2916
DIFF: https://github.com/llvm/llvm-project/commit/c63b0f471ba91382eb9f888b20ef77fe178c2916.diff

LOG: [NFC][LoopVectorize] Make the createStepForVF interface more caller-friendly

The common use case for calling createStepForVF is currently something
like:

  Value *Step = createStepForVF(Builder, ConstantInt::get(Ty, UF), VF);

and it makes more sense to reduce overall lines of code and change the
function to let it create the constant instead. With my patch this
becomes:

  Value *Step = createStepForVF(Builder, Ty, VF, UF);

and the ConstantInt is created instead createStepForVF. A side-effect of
this is that the code in createStepForVF is also becomes simpler.

As part of this patch I've also replaced some calls to getRuntimeVF
with calls to createStepForVF, i.e.

  getRuntimeVF(Builder, Count->getType(), VFactor * UFactor) ->
  createStepForVF(Builder, Count->getType(), VFactor, UFactor)

because this feels semantically better.

Differential Revision: https://reviews.llvm.org/D113122

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index cc6b0607a9ad..0ecce9e274c6 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1103,11 +1103,10 @@ static OptimizationRemarkAnalysis createLVAnalysis(const char *PassName,
 }
 
 /// Return a value for Step multiplied by VF.
-static Value *createStepForVF(IRBuilder<> &B, Constant *Step, ElementCount VF) {
-  assert(isa<ConstantInt>(Step) && "Expected an integer step");
-  Constant *StepVal = ConstantInt::get(
-      Step->getType(),
-      cast<ConstantInt>(Step)->getSExtValue() * VF.getKnownMinValue());
+static Value *createStepForVF(IRBuilder<> &B, Type *Ty, ElementCount VF,
+                              int64_t Step) {
+  assert(Ty->isIntegerTy() && "Expected an integer step");
+  Constant *StepVal = ConstantInt::get(Ty, Step * VF.getKnownMinValue());
   return VF.isScalable() ? B.CreateVScale(StepVal) : StepVal;
 }
 
@@ -2620,8 +2619,7 @@ void InnerLoopVectorizer::buildScalarSteps(Value *ScalarIV, Value *Step,
   }
 
   for (unsigned Part = 0; Part < UF; ++Part) {
-    Value *StartIdx0 =
-        createStepForVF(Builder, ConstantInt::get(IntStepTy, Part), VF);
+    Value *StartIdx0 = createStepForVF(Builder, IntStepTy, VF, Part);
 
     if (!IsUniform && VF.isScalable()) {
       auto *SplatStartIdx = Builder.CreateVectorSplat(VF, StartIdx0);
@@ -2963,7 +2961,8 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(
       if (isMaskRequired) // Reverse of a null all-one mask is a null mask.
         BlockInMaskParts[Part] = reverseVector(BlockInMaskParts[Part]);
     } else {
-      Value *Increment = createStepForVF(Builder, Builder.getInt32(Part), VF);
+      Value *Increment =
+          createStepForVF(Builder, Builder.getInt32Ty(), VF, Part);
       PartPtr = cast<GetElementPtrInst>(
           Builder.CreateGEP(ScalarDataTy, Ptr, Increment));
       PartPtr->setIsInBounds(InBounds);
@@ -3182,7 +3181,7 @@ Value *InnerLoopVectorizer::getOrCreateVectorTripCount(Loop *L) {
 
   Type *Ty = TC->getType();
   // This is where we can make the step a runtime constant.
-  Value *Step = createStepForVF(Builder, ConstantInt::get(Ty, UF), VF);
+  Value *Step = createStepForVF(Builder, Ty, VF, UF);
 
   // If the tail is to be folded by masking, round the number of iterations N
   // up to a multiple of Step instead of rounding down. This is done by first
@@ -3272,8 +3271,7 @@ void InnerLoopVectorizer::emitMinimumIterationCountCheck(Loop *L,
   // If tail is to be folded, vector loop takes care of all iterations.
   Value *CheckMinIters = Builder.getFalse();
   if (!Cost->foldTailByMasking()) {
-    Value *Step =
-        createStepForVF(Builder, ConstantInt::get(Count->getType(), UF), VF);
+    Value *Step = createStepForVF(Builder, Count->getType(), VF, UF);
     CheckMinIters = Builder.CreateICmp(P, Count, Step, "min.iters.check");
   }
   // Create new preheader for vector loop.
@@ -3749,7 +3747,7 @@ BasicBlock *InnerLoopVectorizer::createVectorizedLoopSkeleton() {
   // The loop step is equal to the vectorization factor (num of SIMD elements)
   // times the unroll factor (num of SIMD instructions).
   Builder.SetInsertPoint(&*Lp->getHeader()->getFirstInsertionPt());
-  Value *Step = createStepForVF(Builder, ConstantInt::get(IdxTy, UF), VF);
+  Value *Step = createStepForVF(Builder, IdxTy, VF, UF);
   Value *CountRoundDown = getOrCreateVectorTripCount(Lp);
   Induction =
       createInductionVariable(Lp, StartIdx, CountRoundDown, Step,
@@ -4751,8 +4749,8 @@ void InnerLoopVectorizer::widenPHIInstruction(Instruction *PN,
       }
 
       for (unsigned Part = 0; Part < UF; ++Part) {
-        Value *PartStart = createStepForVF(
-            Builder, ConstantInt::get(PtrInd->getType(), Part), VF);
+        Value *PartStart =
+            createStepForVF(Builder, PtrInd->getType(), VF, Part);
 
         if (NeedsVectorIndex) {
           // Here we cache the whole vector, which means we can support the
@@ -8460,7 +8458,7 @@ BasicBlock *EpilogueVectorizerMainLoop::emitMinimumIterationCountCheck(
       ICmpInst::ICMP_ULE : ICmpInst::ICMP_ULT;
 
   Value *CheckMinIters = Builder.CreateICmp(
-      P, Count, getRuntimeVF(Builder, Count->getType(), VFactor * UFactor),
+      P, Count, createStepForVF(Builder, Count->getType(), VFactor, UFactor),
       "min.iters.check");
 
   if (!ForEpilogue)
@@ -8612,10 +8610,11 @@ EpilogueVectorizerEpilogueLoop::emitMinimumVectorEpilogueIterCountCheck(
   auto P = Cost->requiresScalarEpilogue(EPI.EpilogueVF) ?
       ICmpInst::ICMP_ULE : ICmpInst::ICMP_ULT;
 
-  Value *CheckMinIters = Builder.CreateICmp(
-      P, Count,
-      getRuntimeVF(Builder, Count->getType(), EPI.EpilogueVF * EPI.EpilogueUF),
-      "min.epilog.iters.check");
+  Value *CheckMinIters =
+      Builder.CreateICmp(P, Count,
+                         createStepForVF(Builder, Count->getType(),
+                                         EPI.EpilogueVF, EPI.EpilogueUF),
+                         "min.epilog.iters.check");
 
   ReplaceInstWithInst(
       Insert->getTerminator(),