fixup! Add and use VectorType::getWithSizeAndScalar.

Author: topperc

clang/lib/CodeGen/CGCall.cpp

@@ -1377,14 +1377,8 @@ static llvm::Value *CreateCoercedLoad(Address Src, llvm::Type *Ty,
         auto *PoisonVec = llvm::PoisonValue::get(ScalableDstTy);
         llvm::Value *Result = CGF.Builder.CreateInsertVector(
             ScalableDstTy, PoisonVec, Load, uint64_t(0), "cast.scalable");
-        ScalableDstTy = cast<llvm::ScalableVectorType>(Ty);
-        if (ScalableDstTy->getElementType()->isIntegerTy(1) &&
-            !ScalableDstTy->getElementCount().isKnownMultipleOf(8) &&
-            FixedSrcTy->getElementType()->isIntegerTy(8))
-          ScalableDstTy = llvm::ScalableVectorType::get(
-              ScalableDstTy->getElementType(),
-              llvm::alignTo<8>(
-                  ScalableDstTy->getElementCount().getKnownMinValue()));
+        ScalableDstTy = cast<llvm::ScalableVectorType>(
+            llvm::VectorType::getWithSizeAndScalar(ScalableDstTy, Ty));
         if (Result->getType() != ScalableDstTy)
           Result = CGF.Builder.CreateBitCast(Result, ScalableDstTy);
         if (Result->getType() != Ty)

clang/lib/CodeGen/CGExprScalar.cpp

@@ -2502,14 +2502,8 @@ Value *ScalarExprEmitter::VisitCastExpr(CastExpr *CE) {
           llvm::Value *PoisonVec = llvm::PoisonValue::get(ScalableDstTy);
           llvm::Value *Result = Builder.CreateInsertVector(
               ScalableDstTy, PoisonVec, Src, uint64_t(0), "cast.scalable");
-          ScalableDstTy = cast<llvm::ScalableVectorType>(DstTy);
-          if (ScalableDstTy->getElementType()->isIntegerTy(1) &&
-              !ScalableDstTy->getElementCount().isKnownMultipleOf(8) &&
-              FixedSrcTy->getElementType()->isIntegerTy(8))
-            ScalableDstTy = llvm::ScalableVectorType::get(
-                ScalableDstTy->getElementType(),
-                llvm::alignTo<8>(
-                    ScalableDstTy->getElementCount().getKnownMinValue()));
+          ScalableDstTy = cast<llvm::ScalableVectorType>(
+              llvm::VectorType::getWithSizeAndScalar(ScalableDstTy, DstTy));
           if (Result->getType() != ScalableDstTy)
             Result = Builder.CreateBitCast(Result, ScalableDstTy);
           if (Result->getType() != DstTy)

llvm/include/llvm/IR/DerivedTypes.h

@@ -554,6 +554,23 @@ class VectorType : public Type {
     return VectorType::get(VTy->getElementType(), EltCnt * 2);
   }
 
+  /// This static method attempts to construct a VectorType with the same
+  /// size-in-bits as SizeTy but with an element type that matches the scalar
+  /// type of EltTy. The VectorType is returned on success, nullptr otherwise.
+  static VectorType *getWithSizeAndScalar(VectorType *SizeTy, Type *EltTy) {
+    if (SizeTy->getScalarType() == EltTy->getScalarType())
+      return SizeTy;
+
+    unsigned EltSize = EltTy->getScalarSizeInBits();
+    if (!SizeTy->getPrimitiveSizeInBits().isKnownMultipleOf(EltSize))
+      return nullptr;
+
+    ElementCount EC = SizeTy->getElementCount()
+                          .multiplyCoefficientBy(SizeTy->getScalarSizeInBits())
+                          .divideCoefficientBy(EltSize);
+    return VectorType::get(EltTy->getScalarType(), EC);
+  }
+
   /// Return true if the specified type is valid as a element type.
   static bool isValidElementType(Type *ElemTy);