llvm-6502/include/llvm/Analysis/ConstantFolding.h

79 lines
3.3 KiB
C
Raw Normal View History

//===-- ConstantFolding.h - Analyze constant folding possibilities --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This family of functions determines the possibility of performing constant
// folding.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_CONSTANTFOLDING_H
#define LLVM_ANALYSIS_CONSTANTFOLDING_H
namespace llvm {
class Constant;
class ConstantExpr;
class Instruction;
class TargetData;
class Function;
class Type;
class LLVMContext;
/// ConstantFoldInstruction - Attempt to constant fold the specified
/// instruction. If successful, the constant result is returned, if not, null
/// is returned. Note that this function can only fail when attempting to fold
/// instructions like loads and stores, which have no constant expression form.
///
Constant *ConstantFoldInstruction(Instruction *I, LLVMContext &Context,
const TargetData *TD = 0);
/// ConstantFoldConstantExpression - Attempt to fold the constant expression
/// using the specified TargetData. If successful, the constant result is
/// result is returned, if not, null is returned.
Constant *ConstantFoldConstantExpression(ConstantExpr *CE, LLVMContext &Context,
const TargetData *TD = 0);
/// ConstantFoldInstOperands - Attempt to constant fold an instruction with the
/// specified operands. If successful, the constant result is returned, if not,
/// null is returned. Note that this function can fail when attempting to
/// fold instructions like loads and stores, which have no constant expression
/// form.
///
Constant *ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
Constant*const * Ops, unsigned NumOps,
LLVMContext &Context,
const TargetData *TD = 0);
/// ConstantFoldCompareInstOperands - Attempt to constant fold a compare
/// instruction (icmp/fcmp) with the specified operands. If it fails, it
/// returns a constant expression of the specified operands.
///
Constant *ConstantFoldCompareInstOperands(unsigned Predicate,
Constant*const * Ops, unsigned NumOps,
LLVMContext &Context,
const TargetData *TD = 0);
/// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a
/// getelementptr constantexpr, return the constant value being addressed by the
/// constant expression, or null if something is funny and we can't decide.
Constant *ConstantFoldLoadThroughGEPConstantExpr(Constant *C, ConstantExpr *CE,
LLVMContext &Context);
/// canConstantFoldCallTo - Return true if its even possible to fold a call to
/// the specified function.
bool canConstantFoldCallTo(const Function *F);
/// ConstantFoldCall - Attempt to constant fold a call to the specified function
/// with the specified arguments, returning null if unsuccessful.
Constant *
ConstantFoldCall(Function *F, Constant* const* Operands, unsigned NumOperands);
}
#endif