llvm-6502/include/llvm/Analysis/InstructionSimplify.h
Chris Lattner 81a0dc9115 Teach instsimplify some tricks about exact/nuw/nsw shifts.
improve interfaces to instsimplify to take this info.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125196 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 17:15:04 +00:00

144 lines
6.6 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. This does constant folding
// ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
// returning a constant ("and i32 %x, 0" -> "0") or an already existing value
// ("and i32 %x, %x" -> "%x"). If the simplification is also an instruction
// then it dominates the original instruction.
//
//===----------------------------------------------------------------------===//
#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);
/// SimplifySubInst - Given operands for a Sub, see if we can
/// fold the result. If not, this returns null.
Value *SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
const TargetData *TD = 0, const DominatorTree *DT = 0);
/// SimplifyMulInst - Given operands for a Mul, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyMulInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifySDivInst - Given operands for an SDiv, see if we can
/// fold the result. If not, this returns null.
Value *SimplifySDivInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifyUDivInst - Given operands for a UDiv, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyUDivInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifyFDivInst - Given operands for an FDiv, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyFDivInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
const DominatorTree *DT = 0);
/// SimplifyShlInst - Given operands for a Shl, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
const TargetData *TD = 0, const DominatorTree *DT = 0);
/// SimplifyLShrInst - Given operands for a LShr, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
const TargetData *TD = 0, const DominatorTree *DT=0);
/// SimplifyAShrInst - Given operands for a AShr, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
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);
/// SimplifyXorInst - Given operands for a Xor, see if we can
/// fold the result. If not, this returns null.
Value *SimplifyXorInst(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