LLVM 20.0.0git
Functions
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/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"

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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 ConstantFoldBitCast (Constant *V, Type *DestTy)
 
static ConstantfoldMaybeUndesirableCast (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()

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

Definition at line 986 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 1016 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().

◆ FoldBitCast()

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

◆ 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
opcopcode of the second cast constant expression
Opthe first cast constant expression
DstTydestination type of the first cast

Definition at line 45 of file ConstantFold.cpp.

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

Referenced by llvm::ConstantFoldCastInstruction().

◆ foldMaybeUndesirableCast()

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