llvm-6502/include/llvm/Analysis/InstructionSimplify.h
Duncan Sands d261dc650a Previously SimplifyInstruction could report that an instruction
simplified to itself (this can only happen in unreachable blocks).
Change it to return null instead.  Hopefully this will fix some
buildbot failures.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119490 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-17 08:35:29 +00:00

95 lines
4.1 KiB
C++

//===-- InstructionSimplify.h - Fold instructions into simpler forms ------===//
//
// 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 simpler forms that
// do not require creating new instructions. For example, this does constant
// folding, and can handle identities like (X&0)->0.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
#define LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
namespace llvm {
class DominatorTree;
class Instruction;
class Value;
class TargetData;
/// SimplifyAddInst - Given operands for an Add, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
const TargetData *TD = 0, const DominatorTree *DT = 0);
/// SimplifyAndInst - Given operands for an And, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyAndInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifyOrInst - Given operands for an Or, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyOrInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
/// the result. If not, this returns null.
Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyGEPInst(Value * const *Ops, unsigned NumOps,
const TargetData *TD = 0, const DominatorTree *DT = 0);
//=== Helper functions for higher up the class hierarchy.
/// SimplifyCmpInst - Given operands for a CmpInst, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
const TargetData *TD = 0, const DominatorTree *DT = 0);
/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
const TargetData *TD = 0, const DominatorTree *DT = 0);
/// SimplifyInstruction - See if we can compute a simplified version of this
/// instruction. If not, this returns null.
Value *SimplifyInstruction(Instruction *I, const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// ReplaceAndSimplifyAllUses - Perform From->replaceAllUsesWith(To) and then
/// delete the From instruction. In addition to a basic RAUW, this does a
/// recursive simplification of the updated instructions. This catches
/// things where one simplification exposes other opportunities. This only
/// simplifies and deletes scalar operations, it does not change the CFG.
///
void ReplaceAndSimplifyAllUses(Instruction *From, Value *To,
const TargetData *TD = 0,
const DominatorTree *DT = 0);
} // end namespace llvm
#endif