Split the logic behind CastInst::isNoopCast into a separate static function,

as is done with most other cast opcode predicates.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105008 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-05-28 21:41:37 +00:00
parent c6e02e4056
commit 2c048ea538
2 changed files with 21 additions and 5 deletions

View File

@ -625,6 +625,14 @@ public:
/// platform. Generally, the result of TargetData::getIntPtrType() should be
/// passed in. If that's not available, use Type::Int64Ty, which will make
/// the isNoopCast call conservative.
/// @brief Determine if the described cast is a no-op cast.
static bool isNoopCast(
Instruction::CastOps Opcode, ///< Opcode of cast
const Type *SrcTy, ///< SrcTy of cast
const Type *DstTy, ///< DstTy of cast
const Type *IntPtrTy ///< Integer type corresponding to Ptr types, or null
);
/// @brief Determine if this cast is a no-op cast.
bool isNoopCast(
const Type *IntPtrTy ///< Integer type corresponding to pointer

View File

@ -1911,9 +1911,12 @@ bool CastInst::isLosslessCast() const {
/// # bitcast i32* %x to i8*
/// # bitcast <2 x i32> %x to <4 x i16>
/// # ptrtoint i32* %x to i32 ; on 32-bit plaforms only
/// @brief Determine if a cast is a no-op.
bool CastInst::isNoopCast(const Type *IntPtrTy) const {
switch (getOpcode()) {
/// @brief Determine if the described cast is a no-op.
bool CastInst::isNoopCast(Instruction::CastOps Opcode,
const Type *SrcTy,
const Type *DestTy,
const Type *IntPtrTy) {
switch (Opcode) {
default:
assert(!"Invalid CastOp");
case Instruction::Trunc:
@ -1930,13 +1933,18 @@ bool CastInst::isNoopCast(const Type *IntPtrTy) const {
return true; // BitCast never modifies bits.
case Instruction::PtrToInt:
return IntPtrTy->getScalarSizeInBits() ==
getType()->getScalarSizeInBits();
DestTy->getScalarSizeInBits();
case Instruction::IntToPtr:
return IntPtrTy->getScalarSizeInBits() ==
getOperand(0)->getType()->getScalarSizeInBits();
SrcTy->getScalarSizeInBits();
}
}
/// @brief Determine if a cast is a no-op.
bool CastInst::isNoopCast(const Type *IntPtrTy) const {
return isNoopCast(getOpcode(), getOperand(0)->getType(), getType(), IntPtrTy);
}
/// This function determines if a pair of casts can be eliminated and what
/// opcode should be used in the elimination. This assumes that there are two
/// instructions like this: