InstCombineSelect.cpp revision db125cfaf57cc83e7dd7453de2d509bc8efd0e5e
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. 136976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman Value *NewSI = Builder->CreateSelect(SI.getCondition(), TI->getOperand(0), 137976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman FI->getOperand(0), SI.getName()+".v"); 1388d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI, 139c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getType()); 140c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 141c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 142c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Only handle binary operators here. 143c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<BinaryOperator>(TI)) 144c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 145c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 146c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Figure out if the operations have any operands in common. 147c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *MatchOp, *OtherOpT, *OtherOpF; 148c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool MatchIsOpZero; 149c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0) == FI->getOperand(0)) { 150c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 151c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 152c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 153c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 154c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(1)) { 155c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 156c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 157c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 158c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = false; 159c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (!TI->isCommutative()) { 160c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 161c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(0) == FI->getOperand(1)) { 162c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 163c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 164c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 165c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 166c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(0)) { 167c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 168c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 169c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 170c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 171c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 172c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 173c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 174c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 175c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If we reach here, they do have operations in common. 176976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman Value *NewSI = Builder->CreateSelect(SI.getCondition(), OtherOpT, 177976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman OtherOpF, SI.getName()+".v"); 178c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 179c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TI)) { 180c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (MatchIsOpZero) 181c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), MatchOp, NewSI); 182c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else 183c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp); 184c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 185c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Shouldn't get here"); 186c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 187c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 188c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 189c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool isSelect01(Constant *C1, Constant *C2) { 190c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C1I = dyn_cast<ConstantInt>(C1); 191c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C1I) 192c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 193c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C2I = dyn_cast<ConstantInt>(C2); 194c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C2I) 195c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 1964ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer if (!C1I->isZero() && !C2I->isZero()) // One side must be zero. 1974ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer return false; 1984ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer return C1I->isOne() || C1I->isAllOnesValue() || 1994ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer C2I->isOne() || C2I->isAllOnesValue(); 200c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 201c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 202c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectIntoOp - Try fold the select into one of the operands to 203c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// facilitate further optimization. 204c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal, 205c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal) { 206c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See the comment above GetSelectFoldableOperands for a description of the 207c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // transformation we are doing here. 208c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) { 209c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TVI->hasOneUse() && TVI->getNumOperands() == 2 && 210c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(FalseVal)) { 211c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(TVI)) { 212c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 213c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && FalseVal == TVI->getOperand(0)) { 214c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 215675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) { 216c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 217c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 218c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 219c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 220c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(TVI); 221c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = TVI->getOperand(2-OpToFold); 222c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 2234ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer // between 0, 1 and -1. 224c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 225976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman Value *NewSel = Builder->CreateSelect(SI.getCondition(), OOp, C); 226c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(TVI); 2272bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BinaryOperator *TVI_BO = cast<BinaryOperator>(TVI); 228675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *BO = BinaryOperator::Create(TVI_BO->getOpcode(), 229675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky FalseVal, NewSel); 2302bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<PossiblyExactOperator>(BO)) 2312bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setIsExact(TVI_BO->isExact()); 2322bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<OverflowingBinaryOperator>(BO)) { 2332bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoUnsignedWrap(TVI_BO->hasNoUnsignedWrap()); 2342bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoSignedWrap(TVI_BO->hasNoSignedWrap()); 2352bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky } 2362bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky return BO; 237c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 238c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 239c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 240c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 241c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 242c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 243c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) { 244c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FVI->hasOneUse() && FVI->getNumOperands() == 2 && 245c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(TrueVal)) { 246c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(FVI)) { 247c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 248c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && TrueVal == FVI->getOperand(0)) { 249c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 250675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) { 251c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 252c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 253c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 254c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 255c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(FVI); 256c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = FVI->getOperand(2-OpToFold); 257c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 2584ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer // between 0, 1 and -1. 259c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 260976e7e1cc8282a965cf20ab54a7dce9165d87ea9Eli Friedman Value *NewSel = Builder->CreateSelect(SI.getCondition(), C, OOp); 261c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(FVI); 262675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *FVI_BO = cast<BinaryOperator>(FVI); 263675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky BinaryOperator *BO = BinaryOperator::Create(FVI_BO->getOpcode(), 264675619ca38adf7d5b019e009add88bcac699bf88Nick Lewycky TrueVal, NewSel); 2652bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<PossiblyExactOperator>(BO)) 2662bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setIsExact(FVI_BO->isExact()); 2672bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky if (isa<OverflowingBinaryOperator>(BO)) { 2682bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoUnsignedWrap(FVI_BO->hasNoUnsignedWrap()); 2692bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky BO->setHasNoSignedWrap(FVI_BO->hasNoSignedWrap()); 2702bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky } 2712bf026e3754b167077c62da5698e19b16a3063b1Nick Lewycky return BO; 272c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 273c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 274c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 275c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 276c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 277c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 278c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 279c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 280c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 28117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer/// SimplifyWithOpReplaced - See if V simplifies when its operand Op is 28217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer/// replaced with RepOp. 28317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramerstatic Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp, 28417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer const TargetData *TD) { 28517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // Trivial replacement. 28617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (V == Op) 28717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return RepOp; 28817c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 28917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer Instruction *I = dyn_cast<Instruction>(V); 29017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (!I) 29117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return 0; 29217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 29317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // If this is a binary operator, try to simplify it with the replaced op. 29417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (BinaryOperator *B = dyn_cast<BinaryOperator>(I)) { 29517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (B->getOperand(0) == Op) 29617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), TD); 29717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (B->getOperand(1) == Op) 29817c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, TD); 29917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer } 30017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 3012c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer // Same for CmpInsts. 3022c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer if (CmpInst *C = dyn_cast<CmpInst>(I)) { 3032c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer if (C->getOperand(0) == Op) 3042c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), TD); 3052c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer if (C->getOperand(1) == Op) 3062c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, TD); 3072c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer } 3082c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer 3092c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer // TODO: We could hand off more cases to instsimplify here. 3102c5cc6887412597518ca4a585625b0af1ea71622Benjamin Kramer 31117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // If all operands are constant after substituting Op for RepOp then we can 31217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // constant fold the instruction. 31317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) { 31417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // Build a list of all constant operands. 31517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer SmallVector<Constant*, 8> ConstOps; 31617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { 31717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (I->getOperand(i) == Op) 31817c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer ConstOps.push_back(CRepOp); 31917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i))) 32017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer ConstOps.push_back(COp); 32117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer else 32217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer break; 32317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer } 32417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 32517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // All operands were constants, fold it. 32617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (ConstOps.size() == I->getNumOperands()) 32717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return ConstantFoldInstOperands(I->getOpcode(), I->getType(), 32817c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer ConstOps.data(), ConstOps.size(), TD); 32917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer } 33017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 33117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer return 0; 33217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer} 33317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 334c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// visitSelectInstWithICmp - Visit a SelectInst that has an 335c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// ICmpInst as its first operand. 336c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 337c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI, 338c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI) { 339c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool Changed = false; 340c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst::Predicate Pred = ICI->getPredicate(); 341c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpLHS = ICI->getOperand(0); 342c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpRHS = ICI->getOperand(1); 343c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 344c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 345c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 346c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Check cases where the comparison is with a constant that 347aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // can be adjusted to fit the min/max idiom. We may move or edit ICI 348aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // here, so make sure the select is the only user. 349c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI->hasOneUse()) 350c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(CmpRHS)) { 35146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X < MIN ? T : F --> F 35246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if ((Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_ULT) 35346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser && CI->isMinValue(Pred == ICmpInst::ICMP_SLT)) 35446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser return ReplaceInstUsesWith(SI, FalseVal); 35546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X > MAX ? T : F --> F 35646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else if ((Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_UGT) 35746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser && CI->isMaxValue(Pred == ICmpInst::ICMP_SGT)) 35846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser return ReplaceInstUsesWith(SI, FalseVal); 359c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (Pred) { 360c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: break; 361c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 36246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser case ICmpInst::ICMP_SLT: 363c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 364c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: { 365b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel // These transformations only work for selects over integers. 366db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner IntegerType *SelectTy = dyn_cast<IntegerType>(SI.getType()); 367b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel if (!SelectTy) 368b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel break; 369b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel 37046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Constant *AdjustedRHS; 37146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_SGT) 37246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() + 1); 37346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else // (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_SLT) 37446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = ConstantInt::get(CI->getContext(), CI->getValue() - 1); 37546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 376c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > C ? X : C+1 --> X < C+1 ? C+1 : X 37746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X < C ? X : C-1 --> X > C-1 ? C-1 : X 378c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 37946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) 38046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ; // Nothing to do here. Values match without any sign/zero extension. 38146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 38246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // Types do not match. Instead of calculating this with mixed types 38346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // promote all to the larger type. This enables scalar evolution to 38446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // analyze this expression. 38546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser else if (CmpRHS->getType()->getScalarSizeInBits() 386b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel < SelectTy->getBitWidth()) { 387b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel Constant *sextRHS = ConstantExpr::getSExt(AdjustedRHS, SelectTy); 38846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 38946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X 39046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X 39146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x >u c ? X : C+1 --> X = sext x; X <u C+1 ? C+1 : X 39246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = sext x; x <u c ? X : C-1 --> X = sext x; X >u C-1 ? C-1 : X 39346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (match(TrueVal, m_SExt(m_Specific(CmpLHS))) && 39446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser sextRHS == FalseVal) { 39546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = TrueVal; 39646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = sextRHS; 39746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (match(FalseVal, m_SExt(m_Specific(CmpLHS))) && 39846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser sextRHS == TrueVal) { 39946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = FalseVal; 40046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = sextRHS; 40146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (ICI->isUnsigned()) { 402b686eb9186ebefe54b4d33846eb07e1ab0beb234Frits van Bommel Constant *zextRHS = ConstantExpr::getZExt(AdjustedRHS, SelectTy); 40346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X 40446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X 40546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // zext + signed compare cannot be changed: 40646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser // 0xff <s 0x00, but 0x00ff >s 0x0000 40746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser if (match(TrueVal, m_ZExt(m_Specific(CmpLHS))) && 40846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser zextRHS == FalseVal) { 40946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = TrueVal; 41046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = zextRHS; 41146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else if (match(FalseVal, m_ZExt(m_Specific(CmpLHS))) && 41246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser zextRHS == TrueVal) { 41346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpLHS = FalseVal; 41446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser AdjustedRHS = zextRHS; 41546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 41646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 41746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 41846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 41946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser } else 42046431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser break; 42146431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser 42246431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Pred = ICmpInst::getSwappedPredicate(Pred); 42346431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser CmpRHS = AdjustedRHS; 42446431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser std::swap(FalseVal, TrueVal); 42546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setPredicate(Pred); 42646431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setOperand(0, CmpLHS); 42746431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser ICI->setOperand(1, CmpRHS); 42846431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser SI.setOperand(1, TrueVal); 42946431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser SI.setOperand(2, FalseVal); 430aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser 431aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // Move ICI instruction right before the select instruction. Otherwise 432aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser // the sext/zext value may be defined after the ICI instruction uses it. 433aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser ICI->moveBefore(&SI); 434aa2be8435693dfe73dac64de3e2b6b3f19df1eacTobias Grosser 43546431d7a931ecc54d563a7674977a9a566b1d4fbTobias Grosser Changed = true; 436c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 437c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 438c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 439c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 440c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 4411db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // Transform (X >s -1) ? C1 : C2 --> ((X >>s 31) & (C2 - C1)) + C1 4421db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // and (X <s 0) ? C2 : C1 --> ((X >>s 31) & (C2 - C1)) + C1 4431db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // FIXME: Type and constness constraints could be lifted, but we have to 4441db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // watch code size carefully. We should consider xor instead of 4451db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // sub/add when we decide to do that. 446db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattner if (IntegerType *Ty = dyn_cast<IntegerType>(CmpLHS->getType())) { 4471db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (TrueVal->getType() == Ty) { 4481db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (ConstantInt *Cmp = dyn_cast<ConstantInt>(CmpRHS)) { 4491db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer ConstantInt *C1 = NULL, *C2 = NULL; 4501db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (Pred == ICmpInst::ICMP_SGT && Cmp->isAllOnesValue()) { 4511db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C1 = dyn_cast<ConstantInt>(TrueVal); 4521db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C2 = dyn_cast<ConstantInt>(FalseVal); 4531db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } else if (Pred == ICmpInst::ICMP_SLT && Cmp->isNullValue()) { 4541db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C1 = dyn_cast<ConstantInt>(FalseVal); 4551db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C2 = dyn_cast<ConstantInt>(TrueVal); 4561db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4571db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (C1 && C2) { 4581db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // This shift results in either -1 or 0. 4591db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer Value *AShr = Builder->CreateAShr(CmpLHS, Ty->getBitWidth()-1); 4601db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 4611db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // Check if we can express the operation with a single or. 4621db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (C2->isAllOnesValue()) 4631db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer return ReplaceInstUsesWith(SI, Builder->CreateOr(AShr, C1)); 4641db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 4651db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer Value *And = Builder->CreateAnd(AShr, C2->getValue()-C1->getValue()); 4661db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer return ReplaceInstUsesWith(SI, Builder->CreateAdd(And, C1)); 4671db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4681db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4691db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4701db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 4711db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 47217c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // If we have an equality comparison then we know the value in one of the 47317c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // arms of the select. See if substituting this value into the arm and 47417c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // simplifying the result yields the same value as the other arm. 47517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (Pred == ICmpInst::ICMP_EQ) { 47617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, TD) == TrueVal || 47717c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, TD) == TrueVal) 478c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 47917c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer } else if (Pred == ICmpInst::ICMP_NE) { 48017c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, TD) == FalseVal || 48117c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, TD) == FalseVal) 482c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 483c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 48498cd75027c3db009ffb64aebf613382299858c32Nick Lewycky 48517c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer // NOTE: if we wanted to, this is where to detect integer MIN/MAX 48617c1bb5d55907cf007d100e4f3c5df4699099b9eBenjamin Kramer 48798cd75027c3db009ffb64aebf613382299858c32Nick Lewycky if (isa<Constant>(CmpRHS)) { 48898cd75027c3db009ffb64aebf613382299858c32Nick Lewycky if (CmpLHS == TrueVal && Pred == ICmpInst::ICMP_EQ) { 48998cd75027c3db009ffb64aebf613382299858c32Nick Lewycky // Transform (X == C) ? X : Y -> (X == C) ? C : Y 49098cd75027c3db009ffb64aebf613382299858c32Nick Lewycky SI.setOperand(1, CmpRHS); 49198cd75027c3db009ffb64aebf613382299858c32Nick Lewycky Changed = true; 49298cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } else if (CmpLHS == FalseVal && Pred == ICmpInst::ICMP_NE) { 49398cd75027c3db009ffb64aebf613382299858c32Nick Lewycky // Transform (X != C) ? Y : X -> (X != C) ? Y : C 49498cd75027c3db009ffb64aebf613382299858c32Nick Lewycky SI.setOperand(2, CmpRHS); 49598cd75027c3db009ffb64aebf613382299858c32Nick Lewycky Changed = true; 49698cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } 49798cd75027c3db009ffb64aebf613382299858c32Nick Lewycky } 49898cd75027c3db009ffb64aebf613382299858c32Nick Lewycky 499c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Changed ? &SI : 0; 500c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 501c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 502c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 503c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a 504c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// PHI node (but the two may be in different blocks). See if the true/false 505c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// values (V) are live in all of the predecessor blocks of the PHI. For 506c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// example, cases like this cannot be mapped: 507c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 508c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// X = phi [ C1, BB1], [C2, BB2] 509c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Y = add 510c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Z = select X, Y, 0 511c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 512c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// because Y is not live in BB1/BB2. 513c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 514c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool CanSelectOperandBeMappingIntoPredBlock(const Value *V, 515c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const SelectInst &SI) { 516c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If the value is a non-instruction value like a constant or argument, it 517c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can always be mapped. 518c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const Instruction *I = dyn_cast<Instruction>(V); 519c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (I == 0) return true; 5208d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 521c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If V is a PHI node defined in the same block as the condition PHI, we can 522c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // map the arguments. 523c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const PHINode *CondPHI = cast<PHINode>(SI.getCondition()); 5248d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 525c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (const PHINode *VP = dyn_cast<PHINode>(I)) 526c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (VP->getParent() == CondPHI->getParent()) 527c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 5288d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 529c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise, if the PHI and select are defined in the same block and if V is 530c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // defined in a different block, then we can transform it. 531c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI.getParent() == CondPHI->getParent() && 532c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner I->getParent() != CondPHI->getParent()) 533c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 5348d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 535c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise we have a 'hard' case and we can't tell without doing more 536c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // detailed dominator based analysis, punt. 537c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 538c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 539c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 540c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSPFofSPF - We have an SPF (e.g. a min or max) of an SPF of the form: 5418d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser/// SPF2(SPF1(A, B), C) 542c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSPFofSPF(Instruction *Inner, 543c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF1, 544c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *A, Value *B, 545c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction &Outer, 546c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF2, Value *C) { 547c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C == A || C == B) { 548c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(A, B), B) -> MAX(A, B) 549c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 550c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SPF1 == SPF2) 551c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, Inner); 5528d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 553c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 554c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 555c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) || 556c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) || 557c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) || 558c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN)) 559c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, C); 560c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 5618d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 562c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: MIN(MIN(A, 23), 97) 563c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 564c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 565c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 566c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 56720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// foldSelectICmpAnd - If one of the constants is zero (we know they can't 56820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// both be) and we have an icmp instruction with zero, and we have an 'and' 56920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// with the non-constant value and a power of two we can turn the select 57020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// into a shift on the result of the 'and'. 57120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramerstatic Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal, 57220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *FalseVal, 57320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer InstCombiner::BuilderTy *Builder) { 57420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition()); 57520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!IC || !IC->isEquality()) 57620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 57720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 5786b4972518cff5b0f76ec63fc8b93b74ae64c3f3dBenjamin Kramer if (!match(IC->getOperand(1), m_Zero())) 5796b4972518cff5b0f76ec63fc8b93b74ae64c3f3dBenjamin Kramer return 0; 58020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 58120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *AndRHS; 58220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer Value *LHS = IC->getOperand(0); 58320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (LHS->getType() != SI.getType() || 58420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer !match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS)))) 58520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 58620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 5872f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // If both select arms are non-zero see if we have a select of the form 5882f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic 5892f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // for 'x ? 2^n : 0' and fix the thing up at the end. 5902f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer ConstantInt *Offset = 0; 5912f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if (!TrueVal->isZero() && !FalseVal->isZero()) { 5922f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if ((TrueVal->getValue() - FalseVal->getValue()).isPowerOf2()) 5932f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer Offset = FalseVal; 5942f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer else if ((FalseVal->getValue() - TrueVal->getValue()).isPowerOf2()) 5952f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer Offset = TrueVal; 5962f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer else 5972f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer return 0; 5982f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer 5992f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // Adjust TrueVal and FalseVal to the offset. 6002f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer TrueVal = ConstantInt::get(Builder->getContext(), 6012f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer TrueVal->getValue() - Offset->getValue()); 6022f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer FalseVal = ConstantInt::get(Builder->getContext(), 6032f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer FalseVal->getValue() - Offset->getValue()); 6042f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer } 60520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 60620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Make sure the mask in the 'and' and one of the select arms is a power of 2. 60720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!AndRHS->getValue().isPowerOf2() || 60820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer (!TrueVal->getValue().isPowerOf2() && 60920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer !FalseVal->getValue().isPowerOf2())) 61020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 61120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 61220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Determine which shift is needed to transform result of the 'and' into the 61320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // desired result. 61420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *ValC = !TrueVal->isZero() ? TrueVal : FalseVal; 61520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer unsigned ValZeros = ValC->getValue().logBase2(); 61620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer unsigned AndZeros = AndRHS->getValue().logBase2(); 61720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 61820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer Value *V = LHS; 61920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ValZeros > AndZeros) 62020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateShl(V, ValZeros - AndZeros); 62120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer else if (ValZeros < AndZeros) 62220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateLShr(V, AndZeros - ValZeros); 62320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 62420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Okay, now we know that everything is set up, we just don't know whether we 62520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // have a icmp_ne or icmp_eq and whether the true or false val is the zero. 62620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer bool ShouldNotVal = !TrueVal->isZero(); 62720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE; 62820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ShouldNotVal) 62920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateXor(V, ValC); 6302f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer 6312f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // Apply an offset if needed. 6322f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if (Offset) 6332f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer V = Builder->CreateAdd(V, Offset); 63420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return V; 63520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer} 636c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 637c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInst(SelectInst &SI) { 638c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CondVal = SI.getCondition(); 639c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 640c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 641c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 642047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal, TD)) 643047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return ReplaceInstUsesWith(SI, V); 644c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 645b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy(1)) { 646c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(TrueVal)) { 647c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue()) { 648c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, true, C --> A = or B, C 649c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 650c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 651047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, false, C --> A = and !B, C 652e87ca454ba39e57a34acab42e4391045d4c8c6cfEli Friedman Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 653047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateAnd(NotCond, FalseVal); 654c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) { 655c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue() == false) { 656c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, C, false --> A = and B, C 657c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 658c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 659047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, C, true --> A = or !B, C 660e87ca454ba39e57a34acab42e4391045d4c8c6cfEli Friedman Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 661047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateOr(NotCond, TrueVal); 662c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 6638d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 664c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, b, a -> a&b 665c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, a, b -> a|b 666c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CondVal == TrueVal) 667c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 668c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else if (CondVal == FalseVal) 669c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 670c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 671c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 672c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Selecting between two integer constants? 673c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal)) 674c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) { 675c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, 1, 0 -> zext C to int 676abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->getValue() == 1) 677abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(CondVal, SI.getType()); 678abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 679abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, -1, 0 -> sext C to int 680abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->isAllOnesValue()) 681abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(CondVal, SI.getType()); 6828d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 683abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, 1 -> zext !C to int 684abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->getValue() == 1) { 685abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 686abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(NotCond, SI.getType()); 687c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 688c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 689abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, -1 -> sext !C to int 690abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->isAllOnesValue()) { 691abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 692abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(NotCond, SI.getType()); 693abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner } 69420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 69520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (Value *V = foldSelectICmpAnd(SI, TrueValC, FalseValC, Builder)) 69620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return ReplaceInstUsesWith(SI, V); 697c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 698c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 699c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 700c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) { 701c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) { 702c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 703c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 7048d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 705c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 706c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 707c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 708c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 709c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 710c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 711c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 712c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 713c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 71421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? X : Y -> X 71521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 7168d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 71721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 71821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 71921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 72021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 72121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 72221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 72321dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 724c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 72521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 726c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 727c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 728c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){ 729c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 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) ? Y : X -> Y 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())) 75121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman return ReplaceInstUsesWith(SI, TrueVal); 75221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 753c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 754c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 755c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect ABS 756c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 757c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 758c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 759c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal)) 760c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *Result = visitSelectInstWithICmp(SI, ICI)) 761c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Result; 762c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 763c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TI = dyn_cast<Instruction>(TrueVal)) 764c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FI = dyn_cast<Instruction>(FalseVal)) 765c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->hasOneUse() && FI->hasOneUse()) { 766c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *AddOp = 0, *SubOp = 0; 767c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 768c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z)) 769c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOpcode() == FI->getOpcode()) 770c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *IV = FoldSelectOpOp(SI, TI, FI)) 771c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return IV; 772c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 773c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y))). This is 774c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // even legal for FP. 775c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((TI->getOpcode() == Instruction::Sub && 776c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::Add) || 777c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (TI->getOpcode() == Instruction::FSub && 778c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::FAdd)) { 779c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = FI; SubOp = TI; 780c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((FI->getOpcode() == Instruction::Sub && 781c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::Add) || 782c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (FI->getOpcode() == Instruction::FSub && 783c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::FAdd)) { 784c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = TI; SubOp = FI; 785c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 786c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 787c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp) { 788c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OtherAddOp = 0; 789c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SubOp->getOperand(0) == AddOp->getOperand(0)) { 790c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(1); 791c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) { 792c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(0); 793c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 794c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 795c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OtherAddOp) { 796c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // So at this point we know we have (Y -> OtherAddOp): 797c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, (add X, Y), (sub X, Z) 798c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NegVal; // Compute -Z 79900805fae5b741a9732579050f60cedc7731f6256Eli Friedman if (SI.getType()->isFPOrFPVectorTy()) { 8001eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman NegVal = Builder->CreateFNeg(SubOp->getOperand(1)); 801c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 8021eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman NegVal = Builder->CreateNeg(SubOp->getOperand(1)); 803c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 804c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 805c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewTrueOp = OtherAddOp; 806c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewFalseOp = NegVal; 807c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp != TI) 808c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(NewTrueOp, NewFalseOp); 8091eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman Value *NewSel = 8101eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman Builder->CreateSelect(CondVal, NewTrueOp, 8111eca76a611859d17f8be2c37bab78ccfd95e1f46Eli Friedman NewFalseOp, SI.getName() + ".p"); 812c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 81300805fae5b741a9732579050f60cedc7731f6256Eli Friedman if (SI.getType()->isFPOrFPVectorTy()) 814f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen return BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel); 815f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen else 816f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel); 817c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 818c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 819c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 820c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 821c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into one of our operands. 822b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy()) { 823c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FoldI = FoldSelectIntoOp(SI, TrueVal, FalseVal)) 824c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return FoldI; 8258d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 826c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(a, b), a) -> MAX(a, b) 827c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 828c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 829c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 830c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *LHS, *RHS, *LHS2, *RHS2; 831c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF = MatchSelectPattern(&SI, LHS, RHS)) { 832c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(LHS, LHS2, RHS2)) 833c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2, 834c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, RHS)) 835c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 836c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(RHS, LHS2, RHS2)) 837c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2, 838c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, LHS)) 839c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 840c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 841c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 842c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO. 843c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(-X) -> ABS(X) 844c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(ABS(X)) -> ABS(X) 845c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 846c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 847c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into a phi node if the condition is a select. 8488d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser if (isa<PHINode>(SI.getCondition())) 849c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // The true/false values have to be live in the PHI predecessor's blocks. 850c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CanSelectOperandBeMappingIntoPredBlock(TrueVal, SI) && 851c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CanSelectOperandBeMappingIntoPredBlock(FalseVal, SI)) 852c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *NV = FoldOpIntoPhi(SI)) 853c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return NV; 854c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 855df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (SelectInst *TrueSI = dyn_cast<SelectInst>(TrueVal)) { 856df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (TrueSI->getCondition() == CondVal) { 857df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky SI.setOperand(1, TrueSI->getTrueValue()); 858df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky return &SI; 859df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 860df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 861df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (SelectInst *FalseSI = dyn_cast<SelectInst>(FalseVal)) { 862df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky if (FalseSI->getCondition() == CondVal) { 863df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky SI.setOperand(2, FalseSI->getFalseValue()); 864df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky return &SI; 865df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 866df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky } 867df3bfae1515c826804754616b989b18630fc4d93Nick Lewycky 868c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator::isNot(CondVal)) { 869c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(0, BinaryOperator::getNotArgument(CondVal)); 870c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, FalseVal); 871c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, TrueVal); 872c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return &SI; 873c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 874c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 875c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 876c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 877