InstCombineSelect.cpp revision e87ca454ba39e57a34acab42e4391045d4c8c6cf
11c22c80d71d7031fa1d4acb4d22dd91beb5487e6Chris Lattner//===- InstCombineSelect.cpp ----------------------------------------------===// 2c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 3c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// The LLVM Compiler Infrastructure 4c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 5c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// This file is distributed under the University of Illinois Open Source 6c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// License. See LICENSE.TXT for details. 7c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 8c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner//===----------------------------------------------------------------------===// 9c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 101c22c80d71d7031fa1d4acb4d22dd91beb5487e6Chris Lattner// This file implements the visitSelect function. 11c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 12c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner//===----------------------------------------------------------------------===// 13c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 14c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner#include "InstCombine.h" 15c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner#include "llvm/Support/PatternMatch.h" 16047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner#include "llvm/Analysis/InstructionSimplify.h" 17c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerusing namespace llvm; 18c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerusing namespace PatternMatch; 19c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 20c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// MatchSelectPattern - Pattern match integer [SU]MIN, [SU]MAX, and ABS idioms, 21c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// returning the kind and providing the out parameter results if we 22c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// successfully match. 23c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic SelectPatternFlavor 24c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerMatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) { 25c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *SI = dyn_cast<SelectInst>(V); 26c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI == 0) return SPF_UNKNOWN; 278d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 28c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition()); 29c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI == 0) return SPF_UNKNOWN; 308d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 31c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner LHS = ICI->getOperand(0); 32c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner RHS = ICI->getOperand(1); 338d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 348d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // (icmp X, Y) ? X : Y 35c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI->getTrueValue() == ICI->getOperand(0) && 36c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI->getFalseValue() == ICI->getOperand(1)) { 37c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (ICI->getPredicate()) { 38c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: return SPF_UNKNOWN; // Equality. 39c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 40c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGE: return SPF_UMAX; 41c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: 42c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGE: return SPF_SMAX; 43c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 44c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULE: return SPF_UMIN; 45c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: 46c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLE: return SPF_SMIN; 47c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 48c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 498d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 508d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // (icmp X, Y) ? Y : X 51c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI->getTrueValue() == ICI->getOperand(1) && 52c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI->getFalseValue() == ICI->getOperand(0)) { 53c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (ICI->getPredicate()) { 54c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: return SPF_UNKNOWN; // Equality. 55c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 56c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGE: return SPF_UMIN; 57c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: 58c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGE: return SPF_SMIN; 59c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 60c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULE: return SPF_UMAX; 61c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: 62c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLE: return SPF_SMAX; 63c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 64c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 658d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 66c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: (X > 4) ? X : 5 --> (X >= 5) ? X : 5 --> MAX(X, 5) 678d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 68c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return SPF_UNKNOWN; 69c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 70c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 71c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 72c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableOperands - We want to turn code that looks like this: 73c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = or %A, %B 74c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = select %cond, %C, %A 75c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// into: 76c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = select %cond, %B, 0 77c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = or %A, %C 78c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 79c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Assuming that the specified instruction is an operand to the select, return 80c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// a bitmask indicating which operands of this instruction are foldable if they 81c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// equal the other incoming value of the select. 82c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 83c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic unsigned GetSelectFoldableOperands(Instruction *I) { 84c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 85c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 86c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 87c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 88c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 89c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 90c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 3; // Can fold through either operand. 91c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: // Can only fold on the amount subtracted. 92c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: // Can only fold on the shift amount. 93c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 94c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 95c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 1; 96c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: 97c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // Cannot fold 98c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 99c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 100c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 101c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableConstant - For the same transformation as the previous 102c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// function, return the identity constant that goes into the select. 103c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic Constant *GetSelectFoldableConstant(Instruction *I) { 104c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 105c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: llvm_unreachable("This cannot happen!"); 106c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 107c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: 108c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 109c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 110c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: 111c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 112c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 113c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getNullValue(I->getType()); 114c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 115c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getAllOnesValue(I->getType()); 116c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 117c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ConstantInt::get(I->getType(), 1); 118c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 119c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 120c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 121c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectOpOp - Here we have (select c, TI, FI), and we know that TI and FI 122c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// have the same opcode and only one use each. Try to simplify this. 123c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectOpOp(SelectInst &SI, Instruction *TI, 124c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *FI) { 125c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getNumOperands() == 1) { 126c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If this is a non-volatile load or a cast from the same type, 127c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // merge. 128c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->isCast()) { 129c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0)->getType() != FI->getOperand(0)->getType()) 130c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 131c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 132c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // unknown unary op. 133c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 134c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 135c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Fold this by inserting a select from the input values. 136c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *NewSI = SelectInst::Create(SI.getCondition(), TI->getOperand(0), 137c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOperand(0), SI.getName()+".v"); 138c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSI, SI); 1398d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI, 140c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getType()); 141c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 142c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 143c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Only handle binary operators here. 144c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<BinaryOperator>(TI)) 145c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 146c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 147c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Figure out if the operations have any operands in common. 148c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *MatchOp, *OtherOpT, *OtherOpF; 149c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool MatchIsOpZero; 150c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0) == FI->getOperand(0)) { 151c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 152c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 153c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 154c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 155c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(1)) { 156c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 157c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 158c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 159c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = false; 160c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (!TI->isCommutative()) { 161c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 162c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(0) == FI->getOperand(1)) { 163c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 164c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 165c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 166c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 167c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(0)) { 168c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 169c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 170c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 171c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 172c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 173c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 174c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 175c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 176c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If we reach here, they do have operations in common. 177c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *NewSI = SelectInst::Create(SI.getCondition(), OtherOpT, 178c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF, SI.getName()+".v"); 179c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSI, SI); 180c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 181c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TI)) { 182c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (MatchIsOpZero) 183c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), MatchOp, NewSI); 184c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else 185c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp); 186c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 187c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Shouldn't get here"); 188c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 189c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 190c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 191c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool isSelect01(Constant *C1, Constant *C2) { 192c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C1I = dyn_cast<ConstantInt>(C1); 193c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C1I) 194c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 195c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C2I = dyn_cast<ConstantInt>(C2); 196c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C2I) 197c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 1984ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer if (!C1I->isZero() && !C2I->isZero()) // One side must be zero. 1994ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer return false; 2004ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer return C1I->isOne() || C1I->isAllOnesValue() || 2014ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer C2I->isOne() || C2I->isAllOnesValue(); 202c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 203c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 204c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectIntoOp - Try fold the select into one of the operands to 205c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// facilitate further optimization. 206c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal, 207c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal) { 208c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See the comment above GetSelectFoldableOperands for a description of the 209c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // transformation we are doing here. 210c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) { 211c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TVI->hasOneUse() && TVI->getNumOperands() == 2 && 212c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(FalseVal)) { 213c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(TVI)) { 214c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 215c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && FalseVal == TVI->getOperand(0)) { 216c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 217675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) { 218c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 219c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 220c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 221c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 222c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(TVI); 223c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = TVI->getOperand(2-OpToFold); 224c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 2254ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer // between 0, 1 and -1. 226c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 227c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = SelectInst::Create(SI.getCondition(), OOp, C); 228c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSel, SI); 229c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(TVI); 2302bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BinaryOperator *TVI_BO = cast<BinaryOperator>(TVI); 231675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *BO = BinaryOperator::Create(TVI_BO->getOpcode(), 232675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky FalseVal, NewSel); 2332bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<PossiblyExactOperator>(BO)) 2342bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setIsExact(TVI_BO->isExact()); 2352bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<OverflowingBinaryOperator>(BO)) { 2362bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoUnsignedWrap(TVI_BO->hasNoUnsignedWrap()); 2372bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoSignedWrap(TVI_BO->hasNoSignedWrap()); 2382bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky } 2392bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky return BO; 240c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 241c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 242c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 243c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 244c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 245c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 246c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) { 247c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FVI->hasOneUse() && FVI->getNumOperands() == 2 && 248c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(TrueVal)) { 249c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(FVI)) { 250c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 251c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && TrueVal == FVI->getOperand(0)) { 252c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 253675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) { 254c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 255c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 256c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 257c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 258c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(FVI); 259c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = FVI->getOperand(2-OpToFold); 260c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 2614ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer // between 0, 1 and -1. 262c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 263c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = SelectInst::Create(SI.getCondition(), C, OOp); 264c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSel, SI); 265c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(FVI); 266675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *FVI_BO = cast<BinaryOperator>(FVI); 267675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *BO = BinaryOperator::Create(FVI_BO->getOpcode(), 268675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky TrueVal, NewSel); 2692bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<PossiblyExactOperator>(BO)) 2702bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setIsExact(FVI_BO->isExact()); 2712bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<OverflowingBinaryOperator>(BO)) { 2722bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoUnsignedWrap(FVI_BO->hasNoUnsignedWrap()); 2732bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoSignedWrap(FVI_BO->hasNoSignedWrap()); 2742bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky } 2752bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky return BO; 276c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 277c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 278c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 279c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 280c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 281c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 282c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 283c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 284c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 285c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// visitSelectInstWithICmp - Visit a SelectInst that has an 286c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// ICmpInst as its first operand. 287c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 288c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI, 289c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI) { 290c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool Changed = false; 291c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst::Predicate Pred = ICI->getPredicate(); 292c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpLHS = ICI->getOperand(0); 293c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpRHS = ICI->getOperand(1); 294c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 295c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 296c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 297c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Check cases where the comparison is with a constant that 298aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // can be adjusted to fit the min/max idiom. We may move or edit ICI 299aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // here, so make sure the select is the only user. 300c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI->hasOneUse()) 301c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(CmpRHS)) { 30246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X < MIN ? T : F --> F 30346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if ((Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_ULT) 30446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser && CI->isMinValue(Pred == ICmpInst::ICMP_SLT)) 30546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser return ReplaceInstUsesWith(SI, FalseVal); 30646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X > MAX ? T : F --> F 30746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else if ((Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_UGT) 30846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser && CI->isMaxValue(Pred == ICmpInst::ICMP_SGT)) 30946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser return ReplaceInstUsesWith(SI, FalseVal); 310c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (Pred) { 311c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: break; 312c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 31346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser case ICmpInst::ICMP_SLT: 314c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 315c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: { 316b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel // These transformations only work for selects over integers. 317b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel const IntegerType *SelectTy = dyn_cast<IntegerType>(SI.getType()); 318b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel if (!SelectTy) 319b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel break; 320b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel 32146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Constant *AdjustedRHS; 32246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_SGT) 32346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() + 1); 32446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else // (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_SLT) 32546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() - 1); 32646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 327c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > C ? X : C+1 --> X < C+1 ? C+1 : X 32846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X < C ? X : C-1 --> X > C-1 ? C-1 : X 329c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 33046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) 33146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ; // Nothing to do here. Values match without any sign/zero extension. 33246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 33346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // Types do not match. Instead of calculating this with mixed types 33446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // promote all to the larger type. This enables scalar evolution to 33546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // analyze this expression. 33646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else if (CmpRHS->getType()->getScalarSizeInBits() 337b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel < SelectTy->getBitWidth()) { 338b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel Constant *sextRHS = ConstantExpr::getSExt(AdjustedRHS, SelectTy); 33946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 34046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X 34146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X 34246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x >u c ? X : C+1 --> X = sext x; X <u C+1 ? C+1 : X 34346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x <u c ? X : C-1 --> X = sext x; X >u C-1 ? C-1 : X 34446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (match(TrueVal, m_SExt(m_Specific(CmpLHS))) && 34546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser sextRHS == FalseVal) { 34646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = TrueVal; 34746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = sextRHS; 34846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (match(FalseVal, m_SExt(m_Specific(CmpLHS))) && 34946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser sextRHS == TrueVal) { 35046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = FalseVal; 35146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = sextRHS; 35246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (ICI->isUnsigned()) { 353b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel Constant *zextRHS = ConstantExpr::getZExt(AdjustedRHS, SelectTy); 35446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X 35546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X 35646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // zext + signed compare cannot be changed: 35746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // 0xff <s 0x00, but 0x00ff >s 0x0000 35846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (match(TrueVal, m_ZExt(m_Specific(CmpLHS))) && 35946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser zextRHS == FalseVal) { 36046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = TrueVal; 36146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = zextRHS; 36246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (match(FalseVal, m_ZExt(m_Specific(CmpLHS))) && 36346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser zextRHS == TrueVal) { 36446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = FalseVal; 36546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = zextRHS; 36646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 36746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 36846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 36946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 37046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 37146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 37246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 37346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Pred = ICmpInst::getSwappedPredicate(Pred); 37446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpRHS = AdjustedRHS; 37546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser std::swap(FalseVal, TrueVal); 37646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setPredicate(Pred); 37746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setOperand(0, CmpLHS); 37846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setOperand(1, CmpRHS); 37946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser SI.setOperand(1, TrueVal); 38046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser SI.setOperand(2, FalseVal); 381aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser 382aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // Move ICI instruction right before the select instruction. Otherwise 383aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // the sext/zext value may be defined after the ICI instruction uses it. 384aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser ICI->moveBefore(&SI); 385aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser 38646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Changed = true; 387c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 388c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 389c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 390c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 391c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 3921db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // Transform (X >s -1) ? C1 : C2 --> ((X >>s 31) & (C2 - C1)) + C1 3931db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // and (X <s 0) ? C2 : C1 --> ((X >>s 31) & (C2 - C1)) + C1 3941db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // FIXME: Type and constness constraints could be lifted, but we have to 3951db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // watch code size carefully. We should consider xor instead of 3961db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // sub/add when we decide to do that. 3971db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (const IntegerType *Ty = dyn_cast<IntegerType>(CmpLHS->getType())) { 3981db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (TrueVal->getType() == Ty) { 3991db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (ConstantInt *Cmp = dyn_cast<ConstantInt>(CmpRHS)) { 4001db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer ConstantInt *C1 = NULL, *C2 = NULL; 4011db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (Pred == ICmpInst::ICMP_SGT && Cmp->isAllOnesValue()) { 4021db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C1 = dyn_cast<ConstantInt>(TrueVal); 4031db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C2 = dyn_cast<ConstantInt>(FalseVal); 4041db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } else if (Pred == ICmpInst::ICMP_SLT && Cmp->isNullValue()) { 4051db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C1 = dyn_cast<ConstantInt>(FalseVal); 4061db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C2 = dyn_cast<ConstantInt>(TrueVal); 4071db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4081db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (C1 && C2) { 4091db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // This shift results in either -1 or 0. 4101db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer Value *AShr = Builder->CreateAShr(CmpLHS, Ty->getBitWidth()-1); 4111db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 4121db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // Check if we can express the operation with a single or. 4131db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (C2->isAllOnesValue()) 4141db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer return ReplaceInstUsesWith(SI, Builder->CreateOr(AShr, C1)); 4151db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 4161db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer Value *And = Builder->CreateAnd(AShr, C2->getValue()-C1->getValue()); 4171db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer return ReplaceInstUsesWith(SI, Builder->CreateAdd(And, C1)); 4181db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4191db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4201db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4211db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4221db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 423c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CmpLHS == TrueVal && CmpRHS == FalseVal) { 424c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 425c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_EQ) 426c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 427c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? X : Y -> X 428c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_NE) 429c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 430c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner /// NOTE: if we wanted to, this is where to detect integer MIN/MAX 431c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 432c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (CmpLHS == FalseVal && CmpRHS == TrueVal) { 433c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 434c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_EQ) 435c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 436c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? Y : X -> Y 437c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_NE) 438c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 439c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner /// NOTE: if we wanted to, this is where to detect integer MIN/MAX 440c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 44198cd75027c3db009ffb64aebf613382299858c32Nick Lewycky 44298cd75027c3db009ffb64aebf613382299858c32Nick Lewycky if (isa<Constant>(CmpRHS)) { 44398cd75027c3db009ffb64aebf613382299858c32Nick Lewycky if (CmpLHS == TrueVal && Pred == ICmpInst::ICMP_EQ) { 44498cd75027c3db009ffb64aebf613382299858c32Nick Lewycky // Transform (X == C) ? X : Y -> (X == C) ? C : Y 44598cd75027c3db009ffb64aebf613382299858c32Nick Lewycky SI.setOperand(1, CmpRHS); 44698cd75027c3db009ffb64aebf613382299858c32Nick Lewycky Changed = true; 44798cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } else if (CmpLHS == FalseVal && Pred == ICmpInst::ICMP_NE) { 44898cd75027c3db009ffb64aebf613382299858c32Nick Lewycky // Transform (X != C) ? Y : X -> (X != C) ? Y : C 44998cd75027c3db009ffb64aebf613382299858c32Nick Lewycky SI.setOperand(2, CmpRHS); 45098cd75027c3db009ffb64aebf613382299858c32Nick Lewycky Changed = true; 45198cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } 45298cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } 45398cd75027c3db009ffb64aebf613382299858c32Nick Lewycky 454c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Changed ? &SI : 0; 455c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 456c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 457c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 458c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a 459c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// PHI node (but the two may be in different blocks). See if the true/false 460c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// values (V) are live in all of the predecessor blocks of the PHI. For 461c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// example, cases like this cannot be mapped: 462c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 463c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// X = phi [ C1, BB1], [C2, BB2] 464c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Y = add 465c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Z = select X, Y, 0 466c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 467c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// because Y is not live in BB1/BB2. 468c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 469c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool CanSelectOperandBeMappingIntoPredBlock(const Value *V, 470c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const SelectInst &SI) { 471c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If the value is a non-instruction value like a constant or argument, it 472c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can always be mapped. 473c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const Instruction *I = dyn_cast<Instruction>(V); 474c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (I == 0) return true; 4758d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 476c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If V is a PHI node defined in the same block as the condition PHI, we can 477c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // map the arguments. 478c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const PHINode *CondPHI = cast<PHINode>(SI.getCondition()); 4798d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 480c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (const PHINode *VP = dyn_cast<PHINode>(I)) 481c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (VP->getParent() == CondPHI->getParent()) 482c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 4838d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 484c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise, if the PHI and select are defined in the same block and if V is 485c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // defined in a different block, then we can transform it. 486c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI.getParent() == CondPHI->getParent() && 487c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner I->getParent() != CondPHI->getParent()) 488c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 4898d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 490c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise we have a 'hard' case and we can't tell without doing more 491c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // detailed dominator based analysis, punt. 492c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 493c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 494c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 495c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSPFofSPF - We have an SPF (e.g. a min or max) of an SPF of the form: 4968d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser/// SPF2(SPF1(A, B), C) 497c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSPFofSPF(Instruction *Inner, 498c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF1, 499c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *A, Value *B, 500c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction &Outer, 501c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF2, Value *C) { 502c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C == A || C == B) { 503c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(A, B), B) -> MAX(A, B) 504c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 505c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SPF1 == SPF2) 506c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, Inner); 5078d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 508c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 509c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 510c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) || 511c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) || 512c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) || 513c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN)) 514c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, C); 515c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 5168d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 517c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: MIN(MIN(A, 23), 97) 518c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 519c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 520c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 521c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 52220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// foldSelectICmpAnd - If one of the constants is zero (we know they can't 52320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// both be) and we have an icmp instruction with zero, and we have an 'and' 52420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// with the non-constant value and a power of two we can turn the select 52520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// into a shift on the result of the 'and'. 52620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramerstatic Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal, 52720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *FalseVal, 52820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer InstCombiner::BuilderTy *Builder) { 52920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition()); 53020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!IC || !IC->isEquality()) 53120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 53220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 5336b4972518cff5b0f76ec63fc8b93b74ae64c3f3dBenjamin Kramer if (!match(IC->getOperand(1), m_Zero())) 5346b4972518cff5b0f76ec63fc8b93b74ae64c3f3dBenjamin Kramer return 0; 53520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 53620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *AndRHS; 53720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer Value *LHS = IC->getOperand(0); 53820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (LHS->getType() != SI.getType() || 53920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer !match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS)))) 54020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 54120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 5422f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // If both select arms are non-zero see if we have a select of the form 5432f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic 5442f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // for 'x ? 2^n : 0' and fix the thing up at the end. 5452f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer ConstantInt *Offset = 0; 5462f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if (!TrueVal->isZero() && !FalseVal->isZero()) { 5472f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if ((TrueVal->getValue() - FalseVal->getValue()).isPowerOf2()) 5482f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer Offset = FalseVal; 5492f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer else if ((FalseVal->getValue() - TrueVal->getValue()).isPowerOf2()) 5502f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer Offset = TrueVal; 5512f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer else 5522f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer return 0; 5532f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer 5542f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // Adjust TrueVal and FalseVal to the offset. 5552f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer TrueVal = ConstantInt::get(Builder->getContext(), 5562f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer TrueVal->getValue() - Offset->getValue()); 5572f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer FalseVal = ConstantInt::get(Builder->getContext(), 5582f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer FalseVal->getValue() - Offset->getValue()); 5592f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer } 56020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 56120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Make sure the mask in the 'and' and one of the select arms is a power of 2. 56220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!AndRHS->getValue().isPowerOf2() || 56320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer (!TrueVal->getValue().isPowerOf2() && 56420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer !FalseVal->getValue().isPowerOf2())) 56520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 56620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 56720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Determine which shift is needed to transform result of the 'and' into the 56820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // desired result. 56920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *ValC = !TrueVal->isZero() ? TrueVal : FalseVal; 57020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer unsigned ValZeros = ValC->getValue().logBase2(); 57120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer unsigned AndZeros = AndRHS->getValue().logBase2(); 57220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 57320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer Value *V = LHS; 57420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ValZeros > AndZeros) 57520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateShl(V, ValZeros - AndZeros); 57620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer else if (ValZeros < AndZeros) 57720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateLShr(V, AndZeros - ValZeros); 57820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 57920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Okay, now we know that everything is set up, we just don't know whether we 58020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // have a icmp_ne or icmp_eq and whether the true or false val is the zero. 58120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer bool ShouldNotVal = !TrueVal->isZero(); 58220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE; 58320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ShouldNotVal) 58420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateXor(V, ValC); 5852f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer 5862f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // Apply an offset if needed. 5872f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if (Offset) 5882f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer V = Builder->CreateAdd(V, Offset); 58920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return V; 59020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer} 591c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 592c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInst(SelectInst &SI) { 593c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CondVal = SI.getCondition(); 594c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 595c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 596c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 597047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal, TD)) 598047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return ReplaceInstUsesWith(SI, V); 599c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 600b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy(1)) { 601c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(TrueVal)) { 602c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue()) { 603c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, true, C --> A = or B, C 604c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 605c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 606047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, false, C --> A = and !B, C 607e87ca454ba39e57a34acab42e4391045d4c8c6cfEli Friedman Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 608047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateAnd(NotCond, FalseVal); 609c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) { 610c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue() == false) { 611c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, C, false --> A = and B, C 612c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 613c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 614047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, C, true --> A = or !B, C 615e87ca454ba39e57a34acab42e4391045d4c8c6cfEli Friedman Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 616047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateOr(NotCond, TrueVal); 617c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 6188d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 619c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, b, a -> a&b 620c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, a, b -> a|b 621c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CondVal == TrueVal) 622c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 623c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else if (CondVal == FalseVal) 624c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 625c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 626c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 627c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Selecting between two integer constants? 628c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal)) 629c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) { 630c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, 1, 0 -> zext C to int 631abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->getValue() == 1) 632abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(CondVal, SI.getType()); 633abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 634abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, -1, 0 -> sext C to int 635abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->isAllOnesValue()) 636abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(CondVal, SI.getType()); 6378d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 638abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, 1 -> zext !C to int 639abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->getValue() == 1) { 640abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 641abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(NotCond, SI.getType()); 642c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 643c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 644abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, -1 -> sext !C to int 645abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->isAllOnesValue()) { 646abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 647abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(NotCond, SI.getType()); 648abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner } 64920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 65020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (Value *V = foldSelectICmpAnd(SI, TrueValC, FalseValC, Builder)) 65120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return ReplaceInstUsesWith(SI, V); 652c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 653c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 654c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 655c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) { 656c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) { 657c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 658c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 6598d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 660c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 661c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 662c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 663c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 664c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 665c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 666c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 667c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 668c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 66921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? X : Y -> X 67021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 6718d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 67221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 67321dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 67421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 67521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 67621dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 67721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 67821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 679c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 68021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 681c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 682c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 683c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){ 684c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 685c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 6868d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 687c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 688c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 689c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 690c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 691c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 692c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 693c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 694c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 695c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 69621dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? Y : X -> Y 69721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 6988d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 69921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 70021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 70121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 70221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 70321dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 70421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 70521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 70621dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman return ReplaceInstUsesWith(SI, TrueVal); 70721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 708c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 709c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 710c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect ABS 711c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 712c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 713c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 714c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal)) 715c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *Result = visitSelectInstWithICmp(SI, ICI)) 716c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Result; 717c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 718c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TI = dyn_cast<Instruction>(TrueVal)) 719c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FI = dyn_cast<Instruction>(FalseVal)) 720c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->hasOneUse() && FI->hasOneUse()) { 721c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *AddOp = 0, *SubOp = 0; 722c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 723c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z)) 724c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOpcode() == FI->getOpcode()) 725c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *IV = FoldSelectOpOp(SI, TI, FI)) 726c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return IV; 727c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 728c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y))). This is 729c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // even legal for FP. 730c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((TI->getOpcode() == Instruction::Sub && 731c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::Add) || 732c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (TI->getOpcode() == Instruction::FSub && 733c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::FAdd)) { 734c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = FI; SubOp = TI; 735c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((FI->getOpcode() == Instruction::Sub && 736c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::Add) || 737c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (FI->getOpcode() == Instruction::FSub && 738c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::FAdd)) { 739c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = TI; SubOp = FI; 740c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 741c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 742c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp) { 743c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OtherAddOp = 0; 744c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SubOp->getOperand(0) == AddOp->getOperand(0)) { 745c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(1); 746c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) { 747c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(0); 748c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 749c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 750c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OtherAddOp) { 751c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // So at this point we know we have (Y -> OtherAddOp): 752c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, (add X, Y), (sub X, Z) 753c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NegVal; // Compute -Z 754c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Constant *C = dyn_cast<Constant>(SubOp->getOperand(1))) { 755c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NegVal = ConstantExpr::getNeg(C); 756f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen } else if (SI.getType()->isFloatingPointTy()) { 757f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen NegVal = InsertNewInstBefore( 758f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen BinaryOperator::CreateFNeg(SubOp->getOperand(1), 759f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen "tmp"), SI); 760c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 761c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NegVal = InsertNewInstBefore( 762c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner BinaryOperator::CreateNeg(SubOp->getOperand(1), 763c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner "tmp"), SI); 764c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 765c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 766c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewTrueOp = OtherAddOp; 767c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewFalseOp = NegVal; 768c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp != TI) 769c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(NewTrueOp, NewFalseOp); 770c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = 771c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst::Create(CondVal, NewTrueOp, 772c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewFalseOp, SI.getName() + ".p"); 773c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 774c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel = InsertNewInstBefore(NewSel, SI); 775f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen if (SI.getType()->isFloatingPointTy()) 776f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen return BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel); 777f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen else 778f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel); 779c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 780c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 781c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 782c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 783c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into one of our operands. 784b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy()) { 785c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FoldI = FoldSelectIntoOp(SI, TrueVal, FalseVal)) 786c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return FoldI; 7878d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 788c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(a, b), a) -> MAX(a, b) 789c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 790c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 791c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 792c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *LHS, *RHS, *LHS2, *RHS2; 793c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF = MatchSelectPattern(&SI, LHS, RHS)) { 794c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(LHS, LHS2, RHS2)) 795c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2, 796c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, RHS)) 797c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 798c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(RHS, LHS2, RHS2)) 799c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2, 800c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, LHS)) 801c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 802c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 803c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 804c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO. 805c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(-X) -> ABS(X) 806c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(ABS(X)) -> ABS(X) 807c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 808c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 809c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into a phi node if the condition is a select. 8108d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser if (isa<PHINode>(SI.getCondition())) 811c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // The true/false values have to be live in the PHI predecessor's blocks. 812c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CanSelectOperandBeMappingIntoPredBlock(TrueVal, SI) && 813c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CanSelectOperandBeMappingIntoPredBlock(FalseVal, SI)) 814c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *NV = FoldOpIntoPhi(SI)) 815c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return NV; 816c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 817df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (SelectInst *TrueSI = dyn_cast<SelectInst>(TrueVal)) { 818df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (TrueSI->getCondition() == CondVal) { 819df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky SI.setOperand(1, TrueSI->getTrueValue()); 820df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky return &SI; 821df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 822df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 823df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (SelectInst *FalseSI = dyn_cast<SelectInst>(FalseVal)) { 824df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (FalseSI->getCondition() == CondVal) { 825df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky SI.setOperand(2, FalseSI->getFalseValue()); 826df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky return &SI; 827df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 828df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 829df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky 830c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator::isNot(CondVal)) { 831c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(0, BinaryOperator::getNotArgument(CondVal)); 832c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, FalseVal); 833c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, TrueVal); 834c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return &SI; 835c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 836c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 837c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 838c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 839