Chris Lattner | 9f3c25a | 2009-11-09 22:57:59 +0000 | [diff] [blame] | 1 | //===- InstructionSimplify.cpp - Fold instruction operands ----------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file implements routines for folding instructions into simpler forms |
| 11 | // that do not require creating new instructions. For example, this does |
| 12 | // constant folding, and can handle identities like (X&0)->0. |
| 13 | // |
| 14 | //===----------------------------------------------------------------------===// |
| 15 | |
| 16 | #include "llvm/Analysis/InstructionSimplify.h" |
| 17 | #include "llvm/Analysis/ConstantFolding.h" |
| 18 | #include "llvm/Instructions.h" |
| 19 | using namespace llvm; |
| 20 | |
| 21 | |
| 22 | /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can |
| 23 | /// fold the result. If not, this returns null. |
| 24 | Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, |
| 25 | const TargetData *TD) { |
| 26 | if (Constant *CLHS = dyn_cast<Constant>(LHS)) |
| 27 | if (Constant *CRHS = dyn_cast<Constant>(RHS)) { |
| 28 | Constant *COps[] = {CLHS, CRHS}; |
| 29 | return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, 2, TD); |
| 30 | } |
| 31 | return 0; |
| 32 | } |
| 33 | |
| 34 | |
| 35 | /// SimplifyCompare - Given operands for a CmpInst, see if we can |
| 36 | /// fold the result. |
| 37 | Value *llvm::SimplifyCompare(unsigned Predicate, Value *LHS, Value *RHS, |
| 38 | const TargetData *TD) { |
| 39 | CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate; |
| 40 | |
| 41 | if (Constant *CLHS = dyn_cast<Constant>(LHS)) |
Chris Lattner | 8f73dea | 2009-11-09 23:06:58 +0000 | [diff] [blame^] | 42 | if (Constant *CRHS = dyn_cast<Constant>(RHS)) |
| 43 | return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, TD); |
Chris Lattner | 9f3c25a | 2009-11-09 22:57:59 +0000 | [diff] [blame] | 44 | |
| 45 | // If this is an integer compare and the LHS and RHS are the same, fold it. |
| 46 | if (LHS == RHS) |
| 47 | if (isa<IntegerType>(LHS->getType()) || isa<PointerType>(LHS->getType())) { |
| 48 | if (ICmpInst::isTrueWhenEqual(Pred)) |
| 49 | return ConstantInt::getTrue(LHS->getContext()); |
| 50 | else |
| 51 | return ConstantInt::getFalse(LHS->getContext()); |
| 52 | } |
| 53 | return 0; |
| 54 | } |
| 55 | |