[NFC][VectorCombine] Extract computeAlignmentAfterScalarization() helper function

diff --git a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
index c184c8a..affe4e8 100644 (file)
--- a/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
+++ b/llvm/lib/Transforms/Vectorize/VectorCombine.cpp
@@ -788,6 +788,19 @@ static bool canScalarizeAccess(FixedVectorType *VecTy, Value *Idx,
   return ValidIndices.contains(IdxRange);
 }
 
+/// The memory operation on a vector of \p ScalarType had alignment of
+/// \p VectorAlignment. Compute the maximal, but conservatively correct,
+/// alignment that will be valid for the memory operation on a single scalar
+/// element of the same type with index \p Idx.
+static Align computeAlignmentAfterScalarization(Align VectorAlignment,
+                                                Type *ScalarType, Value *Idx,
+                                                const DataLayout &DL) {
+  if (auto *C = dyn_cast<ConstantInt>(Idx))
+    return commonAlignment(VectorAlignment,
+                           C->getZExtValue() * DL.getTypeStoreSize(ScalarType));
+  return commonAlignment(VectorAlignment, DL.getTypeStoreSize(ScalarType));
+}
+
 // Combine patterns like:
 //   %0 = load <4 x i32>, <4 x i32>* %a
 //   %1 = insertelement <4 x i32> %0, i32 %b, i32 1
@@ -831,15 +844,10 @@ bool VectorCombine::foldSingleElementStore(Instruction &I) {
     Builder.Insert(GEP);
     StoreInst *NSI = Builder.CreateStore(NewElement, GEP);
     NSI->copyMetadata(*SI);
-    Align NewAlignment = std::max(SI->getAlign(), Load->getAlign());
-    if (auto *C = dyn_cast<ConstantInt>(Idx))
-      NewAlignment = commonAlignment(
-          NewAlignment,
-          C->getZExtValue() * DL.getTypeStoreSize(NewElement->getType()));
-    else
-      NewAlignment = commonAlignment(
-          NewAlignment, DL.getTypeStoreSize(NewElement->getType()));
-    NSI->setAlignment(NewAlignment);
+    Align ScalarOpAlignment = computeAlignmentAfterScalarization(
+        std::max(SI->getAlign(), Load->getAlign()), NewElement->getType(), Idx,
+        DL);
+    NSI->setAlignment(ScalarOpAlignment);
     replaceValue(I, *NSI);
     // Need erasing the store manually.
     I.eraseFromParent();