#include "llvm/IR/ConstantFold.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/Support/ErrorHandling.h"

Functions
static unsigned	foldConstantCastPair (unsigned opc, ConstantExpr Op, Type DstTy)
	This function determines which opcode to use to fold two constant cast expressions together.

static Constant *	FoldBitCast (Constant V, Type DestTy)

static Constant *	ExtractConstantBytes (Constant *C, unsigned ByteStart, unsigned ByteSize)
	V is an integer constant which only has a subset of its bytes used.

static Constant *	foldMaybeUndesirableCast (unsigned opc, Constant V, Type DestTy)

static ICmpInst::Predicate	areGlobalsPotentiallyEqual (const GlobalValue GV1, const GlobalValue GV2)

static ICmpInst::Predicate	evaluateICmpRelation (Constant V1, Constant V2)
	This function determines if there is anything we can decide about the two constants provided.

template<typename IndexTy >
static bool	isInBoundsIndices (ArrayRef< IndexTy > Idxs)
	Test whether the given sequence of normalized indices is "inbounds".

static bool	isIndexInRangeOfArrayType (uint64_t NumElements, const ConstantInt *CI)
	Test whether a given ConstantInt is in-range for a SequentialType.

static Constant *	foldGEPOfGEP (GEPOperator GEP, Type PointeeTy, bool InBounds, ArrayRef< Value * > Idxs)

Function Documentation

◆ areGlobalsPotentiallyEqual()

static ICmpInst::Predicate areGlobalsPotentiallyEqual	(	const GlobalValue *	GV1,
		const GlobalValue *	GV2
	)

static

Definition at line 1069 of file ConstantFold.cpp.

References llvm::Type::isEmptyTy(), and llvm::Type::isSized().

Referenced by evaluateICmpRelation().

◆ evaluateICmpRelation()

static ICmpInst::Predicate evaluateICmpRelation	(	Constant *	V1,
		Constant *	V2
	)

static

This function determines if there is anything we can decide about the two constants provided.

This doesn't need to handle simple things like integer comparisons, but should instead handle ConstantExprs and GlobalValues. If we can determine that the two constants have a particular relation to each other, we should return the corresponding ICmp predicate, otherwise return ICmpInst::BAD_ICMP_PREDICATE.

Definition at line 1099 of file ConstantFold.cpp.

References areGlobalsPotentiallyEqual(), assert(), evaluateICmpRelation(), llvm::User::getOperand(), llvm::Value::getType(), llvm::GEPOperator::hasAllZeroIndices(), llvm::GEPOperator::isInBounds(), llvm::Type::isPointerTy(), and llvm::NullPointerIsDefined().

Referenced by llvm::ConstantFoldCompareInstruction(), and evaluateICmpRelation().

◆ ExtractConstantBytes()

static Constant * ExtractConstantBytes	(	Constant *	C,
		unsigned	ByteStart,
		unsigned	ByteSize
	)

static

V is an integer constant which only has a subset of its bytes used.

The bytes used are indicated by ByteStart (which is the first byte used, counting from the least significant byte) and ByteSize, which is the number of bytes used.

This function analyzes the specified constant to see if the specified byte range can be returned as a simplified constant. If so, the constant is returned, otherwise null is returned.

Definition at line 132 of file ConstantFold.cpp.

References assert(), llvm::CallingConv::C, ExtractConstantBytes(), llvm::IntegerType::get(), llvm::Constant::getNullValue(), llvm::ConstantInt::getValue(), llvm::APInt::getZExtValue(), llvm::APInt::lshrInPlace(), llvm::APInt::uge(), and llvm::APInt::ule().

Referenced by llvm::ConstantFoldCastInstruction(), and ExtractConstantBytes().

◆ FoldBitCast()

static Constant * FoldBitCast	(	Constant *	V,
		Type *	DestTy
	)

static

Definition at line 70 of file ConstantFold.cpp.

References FP, llvm::ConstantVector::get(), llvm::Constant::getAllOnesValue(), llvm::ConstantExpr::getBitCast(), llvm::Type::getContext(), llvm::Type::getFltSemantics(), llvm::Type::isFloatingPointTy(), llvm::Type::isIntegerTy(), and llvm::Type::isPPC_FP128Ty().

Referenced by llvm::ConstantFoldCastInstruction(), and llvm::ConstantFoldCastOperand().

◆ foldConstantCastPair()

static unsigned foldConstantCastPair	(	unsigned	opc,
		ConstantExpr *	Op,
		Type *	DstTy
	)

static

This function determines which opcode to use to fold two constant cast expressions together.

It uses CastInst::isEliminableCastPair to determine the opcode. Consequently its just a wrapper around that function. Determine if it is valid to fold a cast of a cast

Parameters