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" 16747032522f9f3b2d9bae71aa303c1a0fd953eee9Eli Friedman#include "llvm/Analysis/ConstantFolding.h" 17047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner#include "llvm/Analysis/InstructionSimplify.h" 18c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerusing namespace llvm; 19c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerusing namespace PatternMatch; 20c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 21c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// MatchSelectPattern - Pattern match integer [SU]MIN, [SU]MAX, and ABS idioms, 22c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// returning the kind and providing the out parameter results if we 23c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// successfully match. 24c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic SelectPatternFlavor 25c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerMatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) { 26c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *SI = dyn_cast<SelectInst>(V); 27c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI == 0) return SPF_UNKNOWN; 288d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 29c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition()); 30c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI == 0) return SPF_UNKNOWN; 318d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 32c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner LHS = ICI->getOperand(0); 33c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner RHS = ICI->getOperand(1); 348d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 358d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // (icmp X, Y) ? X : Y 36c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI->getTrueValue() == ICI->getOperand(0) && 37c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI->getFalseValue() == ICI->getOperand(1)) { 38c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (ICI->getPredicate()) { 39c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: return SPF_UNKNOWN; // Equality. 40c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 41c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGE: return SPF_UMAX; 42c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: 43c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGE: return SPF_SMAX; 44c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 45c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULE: return SPF_UMIN; 46c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: 47c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLE: return SPF_SMIN; 48c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 49c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 508d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 518d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // (icmp X, Y) ? Y : X 52c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI->getTrueValue() == ICI->getOperand(1) && 53c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI->getFalseValue() == ICI->getOperand(0)) { 54c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (ICI->getPredicate()) { 55c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: return SPF_UNKNOWN; // Equality. 56c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 57c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGE: return SPF_UMIN; 58c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: 59c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGE: return SPF_SMIN; 60c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 61c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULE: return SPF_UMAX; 62c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: 63c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLE: return SPF_SMAX; 64c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 65c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 668d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 67c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: (X > 4) ? X : 5 --> (X >= 5) ? X : 5 --> MAX(X, 5) 688d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 69c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return SPF_UNKNOWN; 70c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 71c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 72c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 73c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableOperands - We want to turn code that looks like this: 74c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = or %A, %B 75c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = select %cond, %C, %A 76c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// into: 77c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = select %cond, %B, 0 78c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = or %A, %C 79c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 80c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Assuming that the specified instruction is an operand to the select, return 81c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// a bitmask indicating which operands of this instruction are foldable if they 82c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// equal the other incoming value of the select. 83c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 84c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic unsigned GetSelectFoldableOperands(Instruction *I) { 85c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 86c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 87c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 88c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 89c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 90c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 91c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 3; // Can fold through either operand. 92c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: // Can only fold on the amount subtracted. 93c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: // Can only fold on the shift amount. 94c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 95c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 96c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 1; 97c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: 98c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // Cannot fold 99c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 100c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 101c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 102c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableConstant - For the same transformation as the previous 103c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// function, return the identity constant that goes into the select. 104c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic Constant *GetSelectFoldableConstant(Instruction *I) { 105c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 106c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: llvm_unreachable("This cannot happen!"); 107c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 108c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: 109c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 110c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 111c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: 112c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 113c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 114c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getNullValue(I->getType()); 115c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 116c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getAllOnesValue(I->getType()); 117c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 118c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ConstantInt::get(I->getType(), 1); 119c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 120c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 121c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 122c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectOpOp - Here we have (select c, TI, FI), and we know that TI and FI 123c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// have the same opcode and only one use each. Try to simplify this. 124c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectOpOp(SelectInst &SI, Instruction *TI, 125c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *FI) { 126c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getNumOperands() == 1) { 127c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If this is a non-volatile load or a cast from the same type, 128c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // merge. 129c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->isCast()) { 130c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0)->getType() != FI->getOperand(0)->getType()) 131c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 1322f6622c7bf10b07ab1370b3696d334bd91d7091dNadav Rotem // The select condition may be a vector. We may only change the operand 1332f6622c7bf10b07ab1370b3696d334bd91d7091dNadav Rotem // type if the vector width remains the same (and matches the condition). 1342f6622c7bf10b07ab1370b3696d334bd91d7091dNadav Rotem Type *CondTy = SI.getCondition()->getType(); 1352f6622c7bf10b07ab1370b3696d334bd91d7091dNadav Rotem if (CondTy->isVectorTy() && CondTy->getVectorNumElements() != 1362f6622c7bf10b07ab1370b3696d334bd91d7091dNadav Rotem FI->getOperand(0)->getType()->getVectorNumElements()) 1372f6622c7bf10b07ab1370b3696d334bd91d7091dNadav Rotem return 0; 138c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 139c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // unknown unary op. 140c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 141c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 142c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Fold this by inserting a select from the input values. 143976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman Value *NewSI = Builder->CreateSelect(SI.getCondition(), TI->getOperand(0), 144976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman FI->getOperand(0), SI.getName()+".v"); 1458d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI, 146c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getType()); 147c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 148c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 149c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Only handle binary operators here. 150c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<BinaryOperator>(TI)) 151c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 152c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 153c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Figure out if the operations have any operands in common. 154c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *MatchOp, *OtherOpT, *OtherOpF; 155c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool MatchIsOpZero; 156c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0) == FI->getOperand(0)) { 157c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 158c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 159c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 160c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 161c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(1)) { 162c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 163c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 164c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 165c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = false; 166c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (!TI->isCommutative()) { 167c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 168c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(0) == FI->getOperand(1)) { 169c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 170c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 171c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 172c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 173c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(0)) { 174c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 175c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 176c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 177c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 178c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 179c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 180c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 181c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 182c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If we reach here, they do have operations in common. 183976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman Value *NewSI = Builder->CreateSelect(SI.getCondition(), OtherOpT, 184976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman OtherOpF, SI.getName()+".v"); 185c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 186c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TI)) { 187c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (MatchIsOpZero) 188c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), MatchOp, NewSI); 189c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else 190c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp); 191c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 192c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Shouldn't get here"); 193c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 194c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 195c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool isSelect01(Constant *C1, Constant *C2) { 196c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C1I = dyn_cast<ConstantInt>(C1); 197c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C1I) 198c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 199c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C2I = dyn_cast<ConstantInt>(C2); 200c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C2I) 201c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 2024ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer if (!C1I->isZero() && !C2I->isZero()) // One side must be zero. 2034ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer return false; 2044ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer return C1I->isOne() || C1I->isAllOnesValue() || 2054ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer C2I->isOne() || C2I->isAllOnesValue(); 206c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 207c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 208c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectIntoOp - Try fold the select into one of the operands to 209c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// facilitate further optimization. 210c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal, 211c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal) { 212c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See the comment above GetSelectFoldableOperands for a description of the 213c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // transformation we are doing here. 214c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) { 215c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TVI->hasOneUse() && TVI->getNumOperands() == 2 && 216c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(FalseVal)) { 217c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(TVI)) { 218c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 219c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && FalseVal == TVI->getOperand(0)) { 220c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 221675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) { 222c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 223c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 224c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 225c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 226c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(TVI); 227c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = TVI->getOperand(2-OpToFold); 228c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 2294ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer // between 0, 1 and -1. 230c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 231976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman Value *NewSel = Builder->CreateSelect(SI.getCondition(), OOp, C); 232c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(TVI); 2332bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BinaryOperator *TVI_BO = cast<BinaryOperator>(TVI); 234675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *BO = BinaryOperator::Create(TVI_BO->getOpcode(), 235675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky FalseVal, NewSel); 2362bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<PossiblyExactOperator>(BO)) 2372bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setIsExact(TVI_BO->isExact()); 2382bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<OverflowingBinaryOperator>(BO)) { 2392bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoUnsignedWrap(TVI_BO->hasNoUnsignedWrap()); 2402bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoSignedWrap(TVI_BO->hasNoSignedWrap()); 2412bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky } 2422bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky return BO; 243c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 244c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 245c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 246c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 247c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 248c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 249c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) { 250c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FVI->hasOneUse() && FVI->getNumOperands() == 2 && 251c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(TrueVal)) { 252c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(FVI)) { 253c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 254c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && TrueVal == FVI->getOperand(0)) { 255c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 256675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) { 257c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 258c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 259c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 260c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 261c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(FVI); 262c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = FVI->getOperand(2-OpToFold); 263c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 2644ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer // between 0, 1 and -1. 265c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 266976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman Value *NewSel = Builder->CreateSelect(SI.getCondition(), C, OOp); 267c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(FVI); 268675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *FVI_BO = cast<BinaryOperator>(FVI); 269675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *BO = BinaryOperator::Create(FVI_BO->getOpcode(), 270675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky TrueVal, NewSel); 2712bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<PossiblyExactOperator>(BO)) 2722bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setIsExact(FVI_BO->isExact()); 2732bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<OverflowingBinaryOperator>(BO)) { 2742bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoUnsignedWrap(FVI_BO->hasNoUnsignedWrap()); 2752bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoSignedWrap(FVI_BO->hasNoSignedWrap()); 2762bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky } 2772bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky return BO; 278c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 279c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 280c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 281c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 282c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 283c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 284c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 285c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 286c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 28717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer/// SimplifyWithOpReplaced - See if V simplifies when its operand Op is 28817c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer/// replaced with RepOp. 28917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramerstatic Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp, 290aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier const TargetData *TD, 291aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier const TargetLibraryInfo *TLI) { 29217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // Trivial replacement. 29317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (V == Op) 29417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return RepOp; 29517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 29617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer Instruction *I = dyn_cast<Instruction>(V); 29717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (!I) 29817c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return 0; 29917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 30017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // If this is a binary operator, try to simplify it with the replaced op. 30117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (BinaryOperator *B = dyn_cast<BinaryOperator>(I)) { 30217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (B->getOperand(0) == Op) 303aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), TD, TLI); 30417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (B->getOperand(1) == Op) 305aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, TD, TLI); 30617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer } 30717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 3082c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer // Same for CmpInsts. 3092c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer if (CmpInst *C = dyn_cast<CmpInst>(I)) { 3102c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer if (C->getOperand(0) == Op) 311aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), TD, 312aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier TLI); 3132c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer if (C->getOperand(1) == Op) 314aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, TD, 315aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier TLI); 3162c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer } 3172c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer 3182c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer // TODO: We could hand off more cases to instsimplify here. 3192c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer 32017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // If all operands are constant after substituting Op for RepOp then we can 32117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // constant fold the instruction. 32217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) { 32317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // Build a list of all constant operands. 32417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer SmallVector<Constant*, 8> ConstOps; 32517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { 32617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (I->getOperand(i) == Op) 32717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer ConstOps.push_back(CRepOp); 32817c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i))) 32917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer ConstOps.push_back(COp); 33017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer else 33117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer break; 33217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer } 33317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 33417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // All operands were constants, fold it. 335267236ade35200fec4bea0985d7523dacfdb457dNick Lewycky if (ConstOps.size() == I->getNumOperands()) { 336267236ade35200fec4bea0985d7523dacfdb457dNick Lewycky if (LoadInst *LI = dyn_cast<LoadInst>(I)) 337267236ade35200fec4bea0985d7523dacfdb457dNick Lewycky if (!LI->isVolatile()) 338267236ade35200fec4bea0985d7523dacfdb457dNick Lewycky return ConstantFoldLoadFromConstPtr(ConstOps[0], TD); 339267236ade35200fec4bea0985d7523dacfdb457dNick Lewycky 34017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return ConstantFoldInstOperands(I->getOpcode(), I->getType(), 341aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier ConstOps, TD, TLI); 342267236ade35200fec4bea0985d7523dacfdb457dNick Lewycky } 34317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer } 34417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 34517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return 0; 34617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer} 34717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 348c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// visitSelectInstWithICmp - Visit a SelectInst that has an 349c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// ICmpInst as its first operand. 350c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 351c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI, 352c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI) { 353c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool Changed = false; 354c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst::Predicate Pred = ICI->getPredicate(); 355c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpLHS = ICI->getOperand(0); 356c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpRHS = ICI->getOperand(1); 357c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 358c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 359c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 360c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Check cases where the comparison is with a constant that 361aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // can be adjusted to fit the min/max idiom. We may move or edit ICI 362aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // here, so make sure the select is the only user. 363c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI->hasOneUse()) 364c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(CmpRHS)) { 36546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X < MIN ? T : F --> F 36646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if ((Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_ULT) 36746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser && CI->isMinValue(Pred == ICmpInst::ICMP_SLT)) 36846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser return ReplaceInstUsesWith(SI, FalseVal); 36946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X > MAX ? T : F --> F 37046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else if ((Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_UGT) 37146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser && CI->isMaxValue(Pred == ICmpInst::ICMP_SGT)) 37246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser return ReplaceInstUsesWith(SI, FalseVal); 373c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (Pred) { 374c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: break; 375c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 37646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser case ICmpInst::ICMP_SLT: 377c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 378c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: { 379b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel // These transformations only work for selects over integers. 380db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner IntegerType *SelectTy = dyn_cast<IntegerType>(SI.getType()); 381b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel if (!SelectTy) 382b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel break; 383b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel 38446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Constant *AdjustedRHS; 38546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_SGT) 38646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() + 1); 38746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else // (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_SLT) 38846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() - 1); 38946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 390c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > C ? X : C+1 --> X < C+1 ? C+1 : X 39146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X < C ? X : C-1 --> X > C-1 ? C-1 : X 392c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 39346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) 39446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ; // Nothing to do here. Values match without any sign/zero extension. 39546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 39646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // Types do not match. Instead of calculating this with mixed types 39746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // promote all to the larger type. This enables scalar evolution to 39846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // analyze this expression. 39946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else if (CmpRHS->getType()->getScalarSizeInBits() 400b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel < SelectTy->getBitWidth()) { 401b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel Constant *sextRHS = ConstantExpr::getSExt(AdjustedRHS, SelectTy); 40246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 40346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X 40446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X 40546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x >u c ? X : C+1 --> X = sext x; X <u C+1 ? C+1 : X 40646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x <u c ? X : C-1 --> X = sext x; X >u C-1 ? C-1 : X 40746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (match(TrueVal, m_SExt(m_Specific(CmpLHS))) && 40846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser sextRHS == FalseVal) { 40946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = TrueVal; 41046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = sextRHS; 41146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (match(FalseVal, m_SExt(m_Specific(CmpLHS))) && 41246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser sextRHS == TrueVal) { 41346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = FalseVal; 41446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = sextRHS; 41546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (ICI->isUnsigned()) { 416b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel Constant *zextRHS = ConstantExpr::getZExt(AdjustedRHS, SelectTy); 41746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X 41846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X 41946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // zext + signed compare cannot be changed: 42046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // 0xff <s 0x00, but 0x00ff >s 0x0000 42146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (match(TrueVal, m_ZExt(m_Specific(CmpLHS))) && 42246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser zextRHS == FalseVal) { 42346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = TrueVal; 42446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = zextRHS; 42546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (match(FalseVal, m_ZExt(m_Specific(CmpLHS))) && 42646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser zextRHS == TrueVal) { 42746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = FalseVal; 42846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = zextRHS; 42946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 43046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 43146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 43246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 43346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 43446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 43546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 43646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Pred = ICmpInst::getSwappedPredicate(Pred); 43746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpRHS = AdjustedRHS; 43846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser std::swap(FalseVal, TrueVal); 43946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setPredicate(Pred); 44046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setOperand(0, CmpLHS); 44146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setOperand(1, CmpRHS); 44246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser SI.setOperand(1, TrueVal); 44346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser SI.setOperand(2, FalseVal); 444aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser 445aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // Move ICI instruction right before the select instruction. Otherwise 446aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // the sext/zext value may be defined after the ICI instruction uses it. 447aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser ICI->moveBefore(&SI); 448aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser 44946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Changed = true; 450c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 451c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 452c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 453c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 454c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 4551db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // Transform (X >s -1) ? C1 : C2 --> ((X >>s 31) & (C2 - C1)) + C1 4561db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // and (X <s 0) ? C2 : C1 --> ((X >>s 31) & (C2 - C1)) + C1 4571db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // FIXME: Type and constness constraints could be lifted, but we have to 4581db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // watch code size carefully. We should consider xor instead of 4591db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // sub/add when we decide to do that. 460db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner if (IntegerType *Ty = dyn_cast<IntegerType>(CmpLHS->getType())) { 4611db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (TrueVal->getType() == Ty) { 4621db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (ConstantInt *Cmp = dyn_cast<ConstantInt>(CmpRHS)) { 4631db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer ConstantInt *C1 = NULL, *C2 = NULL; 4641db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (Pred == ICmpInst::ICMP_SGT && Cmp->isAllOnesValue()) { 4651db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C1 = dyn_cast<ConstantInt>(TrueVal); 4661db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C2 = dyn_cast<ConstantInt>(FalseVal); 4671db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } else if (Pred == ICmpInst::ICMP_SLT && Cmp->isNullValue()) { 4681db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C1 = dyn_cast<ConstantInt>(FalseVal); 4691db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C2 = dyn_cast<ConstantInt>(TrueVal); 4701db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4711db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (C1 && C2) { 4721db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // This shift results in either -1 or 0. 4731db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer Value *AShr = Builder->CreateAShr(CmpLHS, Ty->getBitWidth()-1); 4741db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 4751db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // Check if we can express the operation with a single or. 4761db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (C2->isAllOnesValue()) 4771db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer return ReplaceInstUsesWith(SI, Builder->CreateOr(AShr, C1)); 4781db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 4791db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer Value *And = Builder->CreateAnd(AShr, C2->getValue()-C1->getValue()); 4801db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer return ReplaceInstUsesWith(SI, Builder->CreateAdd(And, C1)); 4811db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4821db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4831db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4841db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4851db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 48617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // If we have an equality comparison then we know the value in one of the 48717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // arms of the select. See if substituting this value into the arm and 48817c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // simplifying the result yields the same value as the other arm. 48917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (Pred == ICmpInst::ICMP_EQ) { 490aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD, TLI) == TrueVal || 491aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD, TLI) == TrueVal) 492c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 493aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD, TLI) == FalseVal || 494aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD, TLI) == FalseVal) 49511357d4f40b2b4101ca39c79574171e058866227Nick Lewycky return ReplaceInstUsesWith(SI, FalseVal); 49617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer } else if (Pred == ICmpInst::ICMP_NE) { 497aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD, TLI) == FalseVal || 498aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD, TLI) == FalseVal) 499c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 500aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD, TLI) == TrueVal || 501aab8e28d5e470711d80276bbf717408c3ab966fdChad Rosier SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD, TLI) == TrueVal) 50211357d4f40b2b4101ca39c79574171e058866227Nick Lewycky return ReplaceInstUsesWith(SI, TrueVal); 503c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 50498cd75027c3db009ffb64aebf613382299858c32Nick Lewycky 50517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // NOTE: if we wanted to, this is where to detect integer MIN/MAX 50617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 50737fa1c81ac49dc744899d05a8eb7f038cd1502cdBenjamin Kramer if (CmpRHS != CmpLHS && isa<Constant>(CmpRHS)) { 50898cd75027c3db009ffb64aebf613382299858c32Nick Lewycky if (CmpLHS == TrueVal && Pred == ICmpInst::ICMP_EQ) { 50998cd75027c3db009ffb64aebf613382299858c32Nick Lewycky // Transform (X == C) ? X : Y -> (X == C) ? C : Y 51098cd75027c3db009ffb64aebf613382299858c32Nick Lewycky SI.setOperand(1, CmpRHS); 51198cd75027c3db009ffb64aebf613382299858c32Nick Lewycky Changed = true; 51298cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } else if (CmpLHS == FalseVal && Pred == ICmpInst::ICMP_NE) { 51398cd75027c3db009ffb64aebf613382299858c32Nick Lewycky // Transform (X != C) ? Y : X -> (X != C) ? Y : C 51498cd75027c3db009ffb64aebf613382299858c32Nick Lewycky SI.setOperand(2, CmpRHS); 51598cd75027c3db009ffb64aebf613382299858c32Nick Lewycky Changed = true; 51698cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } 51798cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } 51898cd75027c3db009ffb64aebf613382299858c32Nick Lewycky 519c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Changed ? &SI : 0; 520c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 521c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 522c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 523c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a 524c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// PHI node (but the two may be in different blocks). See if the true/false 525c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// values (V) are live in all of the predecessor blocks of the PHI. For 526c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// example, cases like this cannot be mapped: 527c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 528c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// X = phi [ C1, BB1], [C2, BB2] 529c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Y = add 530c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Z = select X, Y, 0 531c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 532c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// because Y is not live in BB1/BB2. 533c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 534c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool CanSelectOperandBeMappingIntoPredBlock(const Value *V, 535c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const SelectInst &SI) { 536c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If the value is a non-instruction value like a constant or argument, it 537c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can always be mapped. 538c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const Instruction *I = dyn_cast<Instruction>(V); 539c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (I == 0) return true; 5408d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 541c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If V is a PHI node defined in the same block as the condition PHI, we can 542c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // map the arguments. 543c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const PHINode *CondPHI = cast<PHINode>(SI.getCondition()); 5448d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 545c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (const PHINode *VP = dyn_cast<PHINode>(I)) 546c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (VP->getParent() == CondPHI->getParent()) 547c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 5488d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 549c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise, if the PHI and select are defined in the same block and if V is 550c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // defined in a different block, then we can transform it. 551c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI.getParent() == CondPHI->getParent() && 552c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner I->getParent() != CondPHI->getParent()) 553c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 5548d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 555c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise we have a 'hard' case and we can't tell without doing more 556c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // detailed dominator based analysis, punt. 557c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 558c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 559c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 560c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSPFofSPF - We have an SPF (e.g. a min or max) of an SPF of the form: 5618d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser/// SPF2(SPF1(A, B), C) 562c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSPFofSPF(Instruction *Inner, 563c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF1, 564c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *A, Value *B, 565c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction &Outer, 566c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF2, Value *C) { 567c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C == A || C == B) { 568c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(A, B), B) -> MAX(A, B) 569c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 570c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SPF1 == SPF2) 571c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, Inner); 5728d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 573c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 574c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 575c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) || 576c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) || 577c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) || 578c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN)) 579c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, C); 580c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 5818d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 582c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: MIN(MIN(A, 23), 97) 583c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 584c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 585c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 586c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 58720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// foldSelectICmpAnd - If one of the constants is zero (we know they can't 58820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// both be) and we have an icmp instruction with zero, and we have an 'and' 58920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// with the non-constant value and a power of two we can turn the select 59020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// into a shift on the result of the 'and'. 59120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramerstatic Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal, 59220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *FalseVal, 59320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer InstCombiner::BuilderTy *Builder) { 59420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition()); 59520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!IC || !IC->isEquality()) 59620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 59720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 5986b4972518cff5b0f76ec63fc8b93b74ae64c3f3dBenjamin Kramer if (!match(IC->getOperand(1), m_Zero())) 5996b4972518cff5b0f76ec63fc8b93b74ae64c3f3dBenjamin Kramer return 0; 60020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 60120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *AndRHS; 60220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer Value *LHS = IC->getOperand(0); 60320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (LHS->getType() != SI.getType() || 60420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer !match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS)))) 60520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 60620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 6072f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // If both select arms are non-zero see if we have a select of the form 6082f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic 6092f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // for 'x ? 2^n : 0' and fix the thing up at the end. 6102f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer ConstantInt *Offset = 0; 6112f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if (!TrueVal->isZero() && !FalseVal->isZero()) { 6122f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if ((TrueVal->getValue() - FalseVal->getValue()).isPowerOf2()) 6132f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer Offset = FalseVal; 6142f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer else if ((FalseVal->getValue() - TrueVal->getValue()).isPowerOf2()) 6152f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer Offset = TrueVal; 6162f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer else 6172f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer return 0; 6182f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer 6192f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // Adjust TrueVal and FalseVal to the offset. 6202f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer TrueVal = ConstantInt::get(Builder->getContext(), 6212f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer TrueVal->getValue() - Offset->getValue()); 6222f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer FalseVal = ConstantInt::get(Builder->getContext(), 6232f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer FalseVal->getValue() - Offset->getValue()); 6242f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer } 62520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 62620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Make sure the mask in the 'and' and one of the select arms is a power of 2. 62720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!AndRHS->getValue().isPowerOf2() || 62820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer (!TrueVal->getValue().isPowerOf2() && 62920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer !FalseVal->getValue().isPowerOf2())) 63020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 63120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 63220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Determine which shift is needed to transform result of the 'and' into the 63320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // desired result. 63420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *ValC = !TrueVal->isZero() ? TrueVal : FalseVal; 63520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer unsigned ValZeros = ValC->getValue().logBase2(); 63620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer unsigned AndZeros = AndRHS->getValue().logBase2(); 63720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 63820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer Value *V = LHS; 63920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ValZeros > AndZeros) 64020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateShl(V, ValZeros - AndZeros); 64120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer else if (ValZeros < AndZeros) 64220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateLShr(V, AndZeros - ValZeros); 64320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 64420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Okay, now we know that everything is set up, we just don't know whether we 64520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // have a icmp_ne or icmp_eq and whether the true or false val is the zero. 64620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer bool ShouldNotVal = !TrueVal->isZero(); 64720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE; 64820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ShouldNotVal) 64920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateXor(V, ValC); 6502f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer 6512f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // Apply an offset if needed. 6522f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if (Offset) 6532f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer V = Builder->CreateAdd(V, Offset); 65420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return V; 65520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer} 656c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 657c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInst(SelectInst &SI) { 658c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CondVal = SI.getCondition(); 659c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 660c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 661c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 662047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal, TD)) 663047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return ReplaceInstUsesWith(SI, V); 664c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 665b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy(1)) { 666c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(TrueVal)) { 667c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue()) { 668c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, true, C --> A = or B, C 669c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 670c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 671047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, false, C --> A = and !B, C 672e87ca454ba39e57a34acab42e4391045d4c8c6cfEli Friedman Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 673047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateAnd(NotCond, FalseVal); 674c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) { 675c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue() == false) { 676c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, C, false --> A = and B, C 677c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 678c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 679047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, C, true --> A = or !B, C 680e87ca454ba39e57a34acab42e4391045d4c8c6cfEli Friedman Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 681047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateOr(NotCond, TrueVal); 682c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 6838d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 684c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, b, a -> a&b 685c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, a, b -> a|b 686c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CondVal == TrueVal) 687c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 688c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else if (CondVal == FalseVal) 689c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 6904e5a1ab10b62b7ca842afd0e99ac982153f217fbPete Cooper 6914e5a1ab10b62b7ca842afd0e99ac982153f217fbPete Cooper // select a, ~a, b -> (~a)&b 6924e5a1ab10b62b7ca842afd0e99ac982153f217fbPete Cooper // select a, b, ~a -> (~a)|b 6934e5a1ab10b62b7ca842afd0e99ac982153f217fbPete Cooper if (match(TrueVal, m_Not(m_Specific(CondVal)))) 6944e5a1ab10b62b7ca842afd0e99ac982153f217fbPete Cooper return BinaryOperator::CreateAnd(TrueVal, FalseVal); 6954e5a1ab10b62b7ca842afd0e99ac982153f217fbPete Cooper else if (match(FalseVal, m_Not(m_Specific(CondVal)))) 6964e5a1ab10b62b7ca842afd0e99ac982153f217fbPete Cooper return BinaryOperator::CreateOr(TrueVal, FalseVal); 697c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 698c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 699c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Selecting between two integer constants? 700c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal)) 701c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) { 702c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, 1, 0 -> zext C to int 703abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->getValue() == 1) 704abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(CondVal, SI.getType()); 705abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 706abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, -1, 0 -> sext C to int 707abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->isAllOnesValue()) 708abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(CondVal, SI.getType()); 7098d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 710abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, 1 -> zext !C to int 711abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->getValue() == 1) { 712abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 713abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(NotCond, SI.getType()); 714c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 715c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 716abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, -1 -> sext !C to int 717abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->isAllOnesValue()) { 718abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 719abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(NotCond, SI.getType()); 720abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner } 72120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 72220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (Value *V = foldSelectICmpAnd(SI, TrueValC, FalseValC, Builder)) 72320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return ReplaceInstUsesWith(SI, V); 724c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 725c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 726c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 727c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) { 728c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) { 729c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 730c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 7318d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 732c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 733c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 734c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 735c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 736c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 737c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 738c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 739c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 740c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 74121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? X : Y -> X 74221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 7438d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 74421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 74521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 74621dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 74721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 74821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 74921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 75021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 751c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 75221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 753c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 754c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 755c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){ 756c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 757c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 7588d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 759c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 760c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 761c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 762c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 763c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 764c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 765c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 766c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 767c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 76821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? Y : X -> Y 76921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 7708d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 77121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 77221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 77321dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 77421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 77521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 77621dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 77721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 77821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman return ReplaceInstUsesWith(SI, TrueVal); 77921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 780c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 781c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 782c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect ABS 783c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 784c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 785c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 786c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal)) 787c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *Result = visitSelectInstWithICmp(SI, ICI)) 788c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Result; 789c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 790c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TI = dyn_cast<Instruction>(TrueVal)) 791c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FI = dyn_cast<Instruction>(FalseVal)) 792c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->hasOneUse() && FI->hasOneUse()) { 793c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *AddOp = 0, *SubOp = 0; 794c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 795c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z)) 796c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOpcode() == FI->getOpcode()) 797c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *IV = FoldSelectOpOp(SI, TI, FI)) 798c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return IV; 799c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 800c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y))). This is 801c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // even legal for FP. 802c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((TI->getOpcode() == Instruction::Sub && 803c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::Add) || 804c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (TI->getOpcode() == Instruction::FSub && 805c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::FAdd)) { 806c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = FI; SubOp = TI; 807c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((FI->getOpcode() == Instruction::Sub && 808c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::Add) || 809c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (FI->getOpcode() == Instruction::FSub && 810c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::FAdd)) { 811c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = TI; SubOp = FI; 812c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 813c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 814c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp) { 815c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OtherAddOp = 0; 816c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SubOp->getOperand(0) == AddOp->getOperand(0)) { 817c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(1); 818c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) { 819c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(0); 820c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 821c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 822c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OtherAddOp) { 823c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // So at this point we know we have (Y -> OtherAddOp): 824c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, (add X, Y), (sub X, Z) 825c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NegVal; // Compute -Z 82600805fae5b741a9732579050f60cedc7731f6256Eli Friedman if (SI.getType()->isFPOrFPVectorTy()) { 8271eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman NegVal = Builder->CreateFNeg(SubOp->getOperand(1)); 828c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 8291eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman NegVal = Builder->CreateNeg(SubOp->getOperand(1)); 830c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 831c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 832c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewTrueOp = OtherAddOp; 833c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewFalseOp = NegVal; 834c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp != TI) 835c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(NewTrueOp, NewFalseOp); 8361eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman Value *NewSel = 8371eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman Builder->CreateSelect(CondVal, NewTrueOp, 8381eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman NewFalseOp, SI.getName() + ".p"); 839c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 84000805fae5b741a9732579050f60cedc7731f6256Eli Friedman if (SI.getType()->isFPOrFPVectorTy()) 841f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen return BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel); 842f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen else 843f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel); 844c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 845c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 846c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 847c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 848c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into one of our operands. 849b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy()) { 850c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FoldI = FoldSelectIntoOp(SI, TrueVal, FalseVal)) 851c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return FoldI; 8528d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 853c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(a, b), a) -> MAX(a, b) 854c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 855c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 856c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 857c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *LHS, *RHS, *LHS2, *RHS2; 858c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF = MatchSelectPattern(&SI, LHS, RHS)) { 859c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(LHS, LHS2, RHS2)) 860c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2, 861c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, RHS)) 862c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 863c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(RHS, LHS2, RHS2)) 864c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2, 865c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, LHS)) 866c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 867c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 868c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 869c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO. 870c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(-X) -> ABS(X) 871c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(ABS(X)) -> ABS(X) 872c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 873c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 874c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into a phi node if the condition is a select. 8758d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser if (isa<PHINode>(SI.getCondition())) 876c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // The true/false values have to be live in the PHI predecessor's blocks. 877c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CanSelectOperandBeMappingIntoPredBlock(TrueVal, SI) && 878c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CanSelectOperandBeMappingIntoPredBlock(FalseVal, SI)) 879c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *NV = FoldOpIntoPhi(SI)) 880c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return NV; 881c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 882df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (SelectInst *TrueSI = dyn_cast<SelectInst>(TrueVal)) { 883df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (TrueSI->getCondition() == CondVal) { 88475564e35147dd6e36b864946298b6a35417bb9e6Nuno Lopes if (SI.getTrueValue() == TrueSI->getTrueValue()) 88575564e35147dd6e36b864946298b6a35417bb9e6Nuno Lopes return 0; 886df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky SI.setOperand(1, TrueSI->getTrueValue()); 887df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky return &SI; 888df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 889df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 890df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (SelectInst *FalseSI = dyn_cast<SelectInst>(FalseVal)) { 891df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (FalseSI->getCondition() == CondVal) { 89275564e35147dd6e36b864946298b6a35417bb9e6Nuno Lopes if (SI.getFalseValue() == FalseSI->getFalseValue()) 89375564e35147dd6e36b864946298b6a35417bb9e6Nuno Lopes return 0; 894df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky SI.setOperand(2, FalseSI->getFalseValue()); 895df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky return &SI; 896df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 897df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 898df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky 899c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator::isNot(CondVal)) { 900c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(0, BinaryOperator::getNotArgument(CondVal)); 901c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, FalseVal); 902c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, TrueVal); 903c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return &SI; 904c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 905c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 9067971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper if (VectorType* VecTy = dyn_cast<VectorType>(SI.getType())) { 9077971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper unsigned VWidth = VecTy->getNumElements(); 9087971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper APInt UndefElts(VWidth, 0); 9097971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth)); 9107971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper if (Value *V = SimplifyDemandedVectorElts(&SI, AllOnesEltMask, UndefElts)) { 9117971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper if (V != &SI) 9127971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper return ReplaceInstUsesWith(SI, V); 9137971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper return &SI; 9147971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper } 9157971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper } 9167971de4178d3be9b31ac03c20e2b50c3e7f4641cPete Cooper 917c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 918c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 919