[IR] Add getExtendedType() to IntegerType and Type (dispatching to IntegerType or VectorType)

llvm-svn: 372638

include/llvm/IR/DerivedTypes.h

@@ -62,6 +62,11 @@ public:
   /// Get or create an IntegerType instance.
   static IntegerType *get(LLVMContext &C, unsigned NumBits);
 
+  /// Returns type twice as wide the input type.
+  IntegerType *getExtendedType() const {
+    return Type::getIntNTy(getContext(), 2 * getScalarSizeInBits());
+  }
+
   /// Get the number of bits in this IntegerType
   unsigned getBitWidth() const { return getSubclassData(); }
 
@@ -470,9 +475,9 @@ public:
   /// This static method is like getInteger except that the element types are
   /// twice as wide as the elements in the input type.
   static VectorType *getExtendedElementVectorType(VectorType *VTy) {
-    unsigned EltBits = VTy->getElementType()->getPrimitiveSizeInBits();
-    Type *EltTy = IntegerType::get(VTy->getContext(), EltBits * 2);
-    return VectorType::get(EltTy, VTy->getElementCount());
+    assert(VTy->isIntOrIntVectorTy() && "VTy expected to be a vector of ints.");
+    auto *EltTy = cast<IntegerType>(VTy->getElementType());
+    return VectorType::get(EltTy->getExtendedType(), VTy->getElementCount());
   }
 
   // This static method gets a VectorType with the same number of elements as
@@ -603,6 +608,16 @@ public:
   }
 };
 
+Type *Type::getExtendedType() const {
+  assert(
+      isIntOrIntVectorTy() &&
+      "Original type expected to be a vector of integers or a scalar integer.");
+  if (auto *VTy = dyn_cast<VectorType>(this))
+    return VectorType::getExtendedElementVectorType(
+        const_cast<VectorType *>(VTy));
+  return cast<IntegerType>(this)->getExtendedType();
+}
+
 unsigned Type::getPointerAddressSpace() const {
   return cast<PointerType>(getScalarType())->getAddressSpace();
 }

include/llvm/IR/Type.h

@@ -378,6 +378,10 @@ public:
     return ContainedTys[0];
   }
 
+  /// Given scalar/vector integer type, returns a type with elements twice as
+  /// wide as in the original type. For vectors, preserves element count.
+  inline Type *getExtendedType() const;
+
   /// Get the address space of this pointer or pointer vector type.
   inline unsigned getPointerAddressSpace() const;
 

lib/Transforms/InstCombine/InstCombineShifts.cpp

@@ -173,11 +173,7 @@ dropRedundantMaskingOfLeftShiftInput(BinaryOperator *OuterShift,
         return nullptr; // Else we can't perform the fold.
       // The mask must be computed in a type twice as wide to ensure
       // that no bits are lost if the sum-of-shifts is wider than the base type.
-      Type *ExtendedScalarTy = Type::getIntNTy(Ty->getContext(), 2 * BitWidth);
-      Type *ExtendedTy =
-          Ty->isVectorTy()
-              ? VectorType::get(ExtendedScalarTy, Ty->getVectorNumElements())
-              : ExtendedScalarTy;
+      Type *ExtendedTy = Ty->getExtendedType();
       auto *ExtendedSumOfShAmts =
           ConstantExpr::getZExt(SumOfShAmts, ExtendedTy);
       // And compute the mask as usual: ~(-1 << (SumOfShAmts))
@@ -213,11 +209,7 @@ dropRedundantMaskingOfLeftShiftInput(BinaryOperator *OuterShift,
       unsigned BitWidth = Ty->getScalarSizeInBits();
       // The mask must be computed in a type twice as wide to ensure
       // that no bits are lost if the sum-of-shifts is wider than the base type.
-      Type *ExtendedScalarTy = Type::getIntNTy(Ty->getContext(), 2 * BitWidth);
-      Type *ExtendedTy =
-          Ty->isVectorTy()
-              ? VectorType::get(ExtendedScalarTy, Ty->getVectorNumElements())
-              : ExtendedScalarTy;
+      Type *ExtendedTy = Ty->getExtendedType();
       auto *ExtendedNumHighBitsToClear = ConstantExpr::getZExt(
           ConstantExpr::getAdd(
               ConstantExpr::getNeg(ShAmtsDiff),