llvm-6502/include/llvm/Analysis/ConstantFolding.h
Chris Lattner 8f73deaa87 fix ConstantFoldCompareInstOperands to take the LHS/RHS as
individual operands instead of taking a temporary array


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86619 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-09 23:06:58 +00:00

82 lines
3.5 KiB
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//===-- ConstantFolding.h - Fold instructions into constants --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares routines for folding instructions into constants.
//
// Also, to supplement the basic VMCore ConstantExpr simplifications,
// this file declares some additional folding routines that can make use of
// TargetData information. These functions cannot go in VMCore due to library
// dependency issues.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_CONSTANTFOLDING_H
#define LLVM_ANALYSIS_CONSTANTFOLDING_H
namespace llvm {
class Constant;
class ConstantExpr;
class Instruction;
class TargetData;
class Function;
class Type;
/// 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, 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,
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,
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 *LHS, Constant *RHS,
const TargetData *TD = 0);
/// ConstantFoldLoadFromConstPtr - Return the value that a load from C would
/// produce if it is constant and determinable. If this is not determinable,
/// return null.
Constant *ConstantFoldLoadFromConstPtr(Constant *C, 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);
/// 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