[Types] Define a getWithNewBitWidth for Types and make use of it

This is designed to change the bitwidth of a type without altering the number
of vector lanes. Also useful in D68651. Otherwise an NFC.

Differential Revision: https://reviews.llvm.org/D69139

llvm-svn: 375417

llvm/include/llvm/CodeGen/BasicTTIImpl.h

@@ -1149,9 +1149,7 @@ public:
                                                     OpPropsBW);
       // For non-rotates (X != Y) we must add shift-by-zero handling costs.
       if (X != Y) {
-        Type *CondTy = Type::getInt1Ty(RetTy->getContext());
-        if (RetVF > 1)
-          CondTy = VectorType::get(CondTy, RetVF);
+        Type *CondTy = RetTy->getWithNewBitWidth(1);
         Cost += ConcreteTTI->getCmpSelInstrCost(BinaryOperator::ICmp, RetTy,
                                                 CondTy, nullptr);
         Cost += ConcreteTTI->getCmpSelInstrCost(BinaryOperator::Select, RetTy,
@@ -1169,7 +1167,6 @@ public:
   unsigned getIntrinsicInstrCost(
       Intrinsic::ID IID, Type *RetTy, ArrayRef<Type *> Tys, FastMathFlags FMF,
       unsigned ScalarizationCostPassed = std::numeric_limits<unsigned>::max()) {
-    unsigned RetVF = (RetTy->isVectorTy() ? RetTy->getVectorNumElements() : 1);
     auto *ConcreteTTI = static_cast<T *>(this);
 
     SmallVector<unsigned, 2> ISDs;
@@ -1326,9 +1323,7 @@ public:
           /*IsUnsigned=*/false);
     case Intrinsic::sadd_sat:
     case Intrinsic::ssub_sat: {
-      Type *CondTy = Type::getInt1Ty(RetTy->getContext());
-      if (RetVF > 1)
-        CondTy = VectorType::get(CondTy, RetVF);
+      Type *CondTy = RetTy->getWithNewBitWidth(1);
 
       Type *OpTy = StructType::create({RetTy, CondTy});
       Intrinsic::ID OverflowOp = IID == Intrinsic::sadd_sat
@@ -1348,9 +1343,7 @@ public:
     }
     case Intrinsic::uadd_sat:
     case Intrinsic::usub_sat: {
-      Type *CondTy = Type::getInt1Ty(RetTy->getContext());
-      if (RetVF > 1)
-        CondTy = VectorType::get(CondTy, RetVF);
+      Type *CondTy = RetTy->getWithNewBitWidth(1);
 
       Type *OpTy = StructType::create({RetTy, CondTy});
       Intrinsic::ID OverflowOp = IID == Intrinsic::uadd_sat
@@ -1367,9 +1360,7 @@ public:
     case Intrinsic::smul_fix:
     case Intrinsic::umul_fix: {
       unsigned ExtSize = RetTy->getScalarSizeInBits() * 2;
-      Type *ExtTy = Type::getIntNTy(RetTy->getContext(), ExtSize);
-      if (RetVF > 1)
-        ExtTy = VectorType::get(ExtTy, RetVF);
+      Type *ExtTy = RetTy->getWithNewBitWidth(ExtSize);
 
       unsigned ExtOp =
           IID == Intrinsic::smul_fix ? Instruction::SExt : Instruction::ZExt;
@@ -1433,9 +1424,7 @@ public:
       Type *MulTy = RetTy->getContainedType(0);
       Type *OverflowTy = RetTy->getContainedType(1);
       unsigned ExtSize = MulTy->getScalarSizeInBits() * 2;
-      Type *ExtTy = Type::getIntNTy(RetTy->getContext(), ExtSize);
-      if (MulTy->isVectorTy())
-        ExtTy = VectorType::get(ExtTy, MulTy->getVectorNumElements() );
+      Type *ExtTy = MulTy->getWithNewBitWidth(ExtSize);
 
       unsigned ExtOp =
           IID == Intrinsic::smul_fix ? Instruction::SExt : Instruction::ZExt;

llvm/include/llvm/IR/DerivedTypes.h

@@ -571,6 +571,10 @@ bool Type::getVectorIsScalable() const {
   return cast<VectorType>(this)->isScalable();
 }
 
+ElementCount Type::getVectorElementCount() const {
+  return cast<VectorType>(this)->getElementCount();
+}
+
 /// Class to represent pointers.
 class PointerType : public Type {
   explicit PointerType(Type *ElType, unsigned AddrSpace);
@@ -618,6 +622,16 @@ Type *Type::getExtendedType() const {
   return cast<IntegerType>(this)->getExtendedType();
 }
 
+Type *Type::getWithNewBitWidth(unsigned NewBitWidth) const {
+  assert(
+      isIntOrIntVectorTy() &&
+      "Original type expected to be a vector of integers or a scalar integer.");
+  Type *NewType = getIntNTy(getContext(), NewBitWidth);
+  if (isVectorTy())
+    NewType = VectorType::get(NewType, getVectorElementCount());
+  return NewType;
+}
+
 unsigned Type::getPointerAddressSpace() const {
   return cast<PointerType>(getScalarType())->getAddressSpace();
 }

llvm/include/llvm/IR/Type.h

@@ -372,6 +372,7 @@ public:
 
   inline bool getVectorIsScalable() const;
   inline unsigned getVectorNumElements() const;
+  inline ElementCount getVectorElementCount() const;
   Type *getVectorElementType() const {
     assert(getTypeID() == VectorTyID);
     return ContainedTys[0];
@@ -382,6 +383,10 @@ public:
     return ContainedTys[0];
   }
 
+  /// Given an integer or vector type, change the lane bitwidth to NewBitwidth,
+  /// whilst keeping the old number of lanes.
+  inline Type *getWithNewBitWidth(unsigned NewBitWidth) const;
+
   /// 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;