[PATCH] D93677: [LV] Use ScalarEvolution::getURemExpr to reduce duplication.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: SjoerdMeijer, gilr.
Herald added a subscriber: hiraditya.
fhahn requested review of this revision.
Herald added a project: LLVM.

ScalarEvolution should be able to handle both constant and variable trip
counts using getURemExpr, so we do not have to handle them separately.

This is a small simplification of a56280094e08 <https://reviews.llvm.org/rGa56280094e08792516b035390a946ea337a27b97>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D93677

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
@@ -5506,20 +5506,15 @@
          "MaxVF must be a power of 2");
   unsigned MaxVFtimesIC =
       UserIC ? MaxVF.getFixedValue() * UserIC : MaxVF.getFixedValue();
-  if (TC > 0 && TC % MaxVFtimesIC == 0) {
-    // Accept MaxVF if we do not have a tail.
-    LLVM_DEBUG(dbgs() << "LV: No tail will remain for any chosen VF.\n");
-    return MaxVF;
-  }
-
   // Avoid tail folding if the trip count is known to be a multiple of any VF we
   // chose.
   ScalarEvolution *SE = PSE.getSE();
   const SCEV *BackedgeTakenCount = PSE.getBackedgeTakenCount();
   const SCEV *ExitCount = SE->getAddExpr(
       BackedgeTakenCount, SE->getOne(BackedgeTakenCount->getType()));
-  unsigned TCisMultipleOf = 1 << SE->GetMinTrailingZeros(ExitCount);
-  if (TCisMultipleOf % MaxVFtimesIC == 0) {
+  const SCEV *Rem = SE->getURemExpr(
+      ExitCount, SE->getConstant(BackedgeTakenCount->getType(), MaxVFtimesIC));
+  if (Rem->isZero()) {
     // Accept MaxVF if we do not have a tail.
     LLVM_DEBUG(dbgs() << "LV: No tail will remain for any chosen VF.\n");
     return MaxVF;


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