ConstantFold.cpp File Reference

#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/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"

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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 *	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.

Function Documentation

areGlobalsPotentiallyEqual()

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

static

Definition at line 963 of file ConstantFold.cpp.

References llvm::CmpInst::BAD_ICMP_PREDICATE, llvm::dyn_cast(), llvm::CmpInst::ICMP_NE, and llvm::isa().

Referenced by evaluateICmpRelation().

evaluateICmpRelation()

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 993 of file ConstantFold.cpp.

References areGlobalsPotentiallyEqual(), assert(), llvm::CmpInst::BAD_ICMP_PREDICATE, llvm::cast(), llvm::dyn_cast(), evaluateICmpRelation(), llvm::User::getOperand(), llvm::CmpInst::getSwappedPredicate(), llvm::Value::getType(), llvm::GEPOperator::hasAllZeroIndices(), llvm::CmpInst::ICMP_EQ, llvm::CmpInst::ICMP_NE, llvm::CmpInst::ICMP_UGT, llvm::isa(), llvm::GEPOperator::isInBounds(), llvm::Type::isPointerTy(), and llvm::NullPointerIsDefined().

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

FoldBitCast()

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

static

Definition at line 69 of file ConstantFold.cpp.

References llvm::dyn_cast(), FP, llvm::ConstantVector::get(), llvm::Constant::getAllOnesValue(), llvm::ConstantExpr::getBitCast(), llvm::Type::getFltSemantics(), llvm::Type::getScalarSizeInBits(), llvm::Type::getScalarType(), llvm::isa(), llvm::Type::isFPOrFPVectorTy(), llvm::Type::isIntOrIntVectorTy(), and llvm::Type::isPPC_FP128Ty().

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

foldConstantCastPair()

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

opc	opcode of the second cast constant expression
Op	the first cast constant expression
DstTy	destination type of the first cast

Definition at line 44 of file ConstantFold.cpp.

References assert(), llvm::Type::getContext(), llvm::Type::getInt64Ty(), llvm::Instruction::isCast(), llvm::CastInst::isEliminableCastPair(), and llvm::Type::isFirstClassType().

Referenced by llvm::ConstantFoldCastInstruction().

foldMaybeUndesirableCast()

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

static

Definition at line 124 of file ConstantFold.cpp.

References llvm::ConstantFoldCastInstruction(), llvm::ConstantExpr::getCast(), and llvm::ConstantExpr::isDesirableCastOp().

Referenced by llvm::ConstantFoldCastInstruction().