[llvm] fec503d - [SLP][NFC]Add safe createExtractVector and use instead Builder.CreateExtractVector

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2025-01-17T11:46:46-08:00
New Revision: fec503d1a3f48e600d0a8e108757dedba909f40c

URL: https://github.com/llvm/llvm-project/commit/fec503d1a3f48e600d0a8e108757dedba909f40c
DIFF: https://github.com/llvm/llvm-project/commit/fec503d1a3f48e600d0a8e108757dedba909f40c.diff

LOG: [SLP][NFC]Add safe createExtractVector and use instead Builder.CreateExtractVector

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index b0b8f8249d657b..0bf01a8c680bfd 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -4995,6 +4995,23 @@ static Value *createInsertVector(
   return Vec;
 }
 
+/// Correctly creates extract_subvector, checking that the index is multiple of
+/// the subvectors length. Otherwise, generates shuffle using \p Generator or
+/// using default shuffle.
+static Value *createExtractVector(IRBuilderBase &Builder, Value *Vec,
+                                  unsigned SubVecVF, unsigned Index) {
+  if (Index % SubVecVF == 0) {
+    VectorType *SubVecTy =
+        getWidenedType(Vec->getType()->getScalarType(), SubVecVF);
+    return Builder.CreateExtractVector(SubVecTy, Vec, Builder.getInt64(Index));
+  }
+  // Create shuffle, extract_subvector requires that index is multiple of
+  // the subvector length.
+  SmallVector<int> Mask(SubVecVF, PoisonMaskElem);
+  std::iota(Mask.begin(), Mask.end(), Index);
+  return Builder.CreateShuffleVector(Vec, Mask);
+}
+
 BoUpSLP::LoadsState
 BoUpSLP::canVectorizeLoads(ArrayRef<Value *> VL, const Value *VL0,
                            SmallVectorImpl<unsigned> &Order,
@@ -16550,10 +16567,8 @@ BoUpSLP::vectorizeTree(const ExtraValueToDebugLocsMap &ExternallyUsedValues,
             // When REVEC is enabled, we need to extract a vector.
             // Note: The element size of Scalar may be 
diff erent from the
             // element size of Vec.
-            Ex = Builder.CreateExtractVector(
-                FixedVectorType::get(Vec->getType()->getScalarType(),
-                                     VecTyNumElements),
-                Vec, Builder.getInt64(ExternalUse.Lane * VecTyNumElements));
+            Ex = createExtractVector(Builder, Vec, VecTyNumElements,
+                                     ExternalUse.Lane * VecTyNumElements);
           } else {
             Ex = Builder.CreateExtractElement(Vec, Lane);
           }