InstCombineSelect.cpp revision abb992d6a3d2dc05d3f3c62a367ea8977a7dd070
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" 16c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerusing namespace llvm; 17c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerusing namespace PatternMatch; 18c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 19c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// MatchSelectPattern - Pattern match integer [SU]MIN, [SU]MAX, and ABS idioms, 20c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// returning the kind and providing the out parameter results if we 21c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// successfully match. 22c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic SelectPatternFlavor 23c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerMatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) { 24c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *SI = dyn_cast<SelectInst>(V); 25c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI == 0) return SPF_UNKNOWN; 26c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 27c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition()); 28c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI == 0) return SPF_UNKNOWN; 29c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 30c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner LHS = ICI->getOperand(0); 31c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner RHS = ICI->getOperand(1); 32c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 33c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // (icmp X, Y) ? X : Y 34c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI->getTrueValue() == ICI->getOperand(0) && 35c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI->getFalseValue() == ICI->getOperand(1)) { 36c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (ICI->getPredicate()) { 37c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: return SPF_UNKNOWN; // Equality. 38c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 39c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGE: return SPF_UMAX; 40c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: 41c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGE: return SPF_SMAX; 42c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 43c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULE: return SPF_UMIN; 44c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: 45c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLE: return SPF_SMIN; 46c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 47c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 48c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 49c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // (icmp X, Y) ? Y : X 50c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI->getTrueValue() == ICI->getOperand(1) && 51c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI->getFalseValue() == ICI->getOperand(0)) { 52c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (ICI->getPredicate()) { 53c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: return SPF_UNKNOWN; // Equality. 54c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 55c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGE: return SPF_UMIN; 56c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: 57c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGE: return SPF_SMIN; 58c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 59c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULE: return SPF_UMAX; 60c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: 61c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLE: return SPF_SMAX; 62c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 63c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 64c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 65c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: (X > 4) ? X : 5 --> (X >= 5) ? X : 5 --> MAX(X, 5) 66c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 67c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return SPF_UNKNOWN; 68c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 69c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 70c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 71c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableOperands - We want to turn code that looks like this: 72c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = or %A, %B 73c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = select %cond, %C, %A 74c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// into: 75c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = select %cond, %B, 0 76c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = or %A, %C 77c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 78c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Assuming that the specified instruction is an operand to the select, return 79c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// a bitmask indicating which operands of this instruction are foldable if they 80c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// equal the other incoming value of the select. 81c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 82c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic unsigned GetSelectFoldableOperands(Instruction *I) { 83c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 84c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 85c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 86c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 87c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 88c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 89c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 3; // Can fold through either operand. 90c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: // Can only fold on the amount subtracted. 91c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: // Can only fold on the shift amount. 92c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 93c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 94c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 1; 95c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: 96c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // Cannot fold 97c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 98c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 99c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 100c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableConstant - For the same transformation as the previous 101c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// function, return the identity constant that goes into the select. 102c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic Constant *GetSelectFoldableConstant(Instruction *I) { 103c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 104c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: llvm_unreachable("This cannot happen!"); 105c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 106c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: 107c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 108c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 109c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: 110c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 111c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 112c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getNullValue(I->getType()); 113c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 114c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getAllOnesValue(I->getType()); 115c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 116c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ConstantInt::get(I->getType(), 1); 117c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 118c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 119c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 120c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectOpOp - Here we have (select c, TI, FI), and we know that TI and FI 121c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// have the same opcode and only one use each. Try to simplify this. 122c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectOpOp(SelectInst &SI, Instruction *TI, 123c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *FI) { 124c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getNumOperands() == 1) { 125c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If this is a non-volatile load or a cast from the same type, 126c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // merge. 127c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->isCast()) { 128c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0)->getType() != FI->getOperand(0)->getType()) 129c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 130c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 131c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // unknown unary op. 132c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 133c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 134c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Fold this by inserting a select from the input values. 135c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *NewSI = SelectInst::Create(SI.getCondition(), TI->getOperand(0), 136c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOperand(0), SI.getName()+".v"); 137c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSI, SI); 138c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 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. 176c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *NewSI = SelectInst::Create(SI.getCondition(), OtherOpT, 177c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF, SI.getName()+".v"); 178c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSI, SI); 179c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 180c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TI)) { 181c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (MatchIsOpZero) 182c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), MatchOp, NewSI); 183c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else 184c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp); 185c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 186c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Shouldn't get here"); 187c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 188c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 189c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 190c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool isSelect01(Constant *C1, Constant *C2) { 191c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C1I = dyn_cast<ConstantInt>(C1); 192c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C1I) 193c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 194c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C2I = dyn_cast<ConstantInt>(C2); 195c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C2I) 196c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 197c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return (C1I->isZero() || C1I->isOne()) && (C2I->isZero() || C2I->isOne()); 198c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 199c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 200c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectIntoOp - Try fold the select into one of the operands to 201c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// facilitate further optimization. 202c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal, 203c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal) { 204c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See the comment above GetSelectFoldableOperands for a description of the 205c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // transformation we are doing here. 206c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) { 207c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TVI->hasOneUse() && TVI->getNumOperands() == 2 && 208c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(FalseVal)) { 209c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(TVI)) { 210c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 211c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && FalseVal == TVI->getOperand(0)) { 212c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 213c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) { 214c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 215c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 216c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 217c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 218c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(TVI); 219c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = TVI->getOperand(2-OpToFold); 220c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 221c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // between 0 and 1. 222c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 223c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = SelectInst::Create(SI.getCondition(), OOp, C); 224c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSel, SI); 225c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(TVI); 226c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TVI)) 227c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), FalseVal, NewSel); 228c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Unknown instruction!!"); 229c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 230c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 231c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 232c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 233c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 234c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 235c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) { 236c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FVI->hasOneUse() && FVI->getNumOperands() == 2 && 237c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(TrueVal)) { 238c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(FVI)) { 239c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 240c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && TrueVal == FVI->getOperand(0)) { 241c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 242c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) { 243c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 244c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 245c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 246c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 247c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(FVI); 248c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = FVI->getOperand(2-OpToFold); 249c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 250c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // between 0 and 1. 251c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 252c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = SelectInst::Create(SI.getCondition(), C, OOp); 253c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSel, SI); 254c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(FVI); 255c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(FVI)) 256c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), TrueVal, NewSel); 257c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Unknown instruction!!"); 258c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 259c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 260c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 261c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 262c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 263c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 264c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 265c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 266c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 267c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// visitSelectInstWithICmp - Visit a SelectInst that has an 268c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// ICmpInst as its first operand. 269c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 270c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI, 271c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI) { 272c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool Changed = false; 273c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst::Predicate Pred = ICI->getPredicate(); 274c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpLHS = ICI->getOperand(0); 275c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpRHS = ICI->getOperand(1); 276c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 277c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 278c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 279c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Check cases where the comparison is with a constant that 280c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can be adjusted to fit the min/max idiom. We may edit ICI in 281c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // place here, so make sure the select is the only user. 282c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI->hasOneUse()) 283c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(CmpRHS)) { 284c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (Pred) { 285c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: break; 286c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 287c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: { 288c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X < MIN ? T : F --> F 289c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CI->isMinValue(Pred == ICmpInst::ICMP_SLT)) 290c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 291c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X < C ? X : C-1 --> X > C-1 ? C-1 : X 292c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *AdjustedRHS = 293c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt::get(CI->getContext(), CI->getValue()-1); 294c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 295c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) { 296c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Pred = ICmpInst::getSwappedPredicate(Pred); 297c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CmpRHS = AdjustedRHS; 298c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(FalseVal, TrueVal); 299c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setPredicate(Pred); 300c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setOperand(1, CmpRHS); 301c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, TrueVal); 302c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, FalseVal); 303c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Changed = true; 304c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 305c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 306c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 307c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 308c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: { 309c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > MAX ? T : F --> F 310c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CI->isMaxValue(Pred == ICmpInst::ICMP_SGT)) 311c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 312c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > C ? X : C+1 --> X < C+1 ? C+1 : X 313c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *AdjustedRHS = 314c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt::get(CI->getContext(), CI->getValue()+1); 315c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 316c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) { 317c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Pred = ICmpInst::getSwappedPredicate(Pred); 318c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CmpRHS = AdjustedRHS; 319c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(FalseVal, TrueVal); 320c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setPredicate(Pred); 321c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setOperand(1, CmpRHS); 322c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, TrueVal); 323c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, FalseVal); 324c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Changed = true; 325c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 326c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 327c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 328c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 329c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 330c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 331c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CmpLHS == TrueVal && CmpRHS == FalseVal) { 332c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 333c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_EQ) 334c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 335c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? X : Y -> X 336c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_NE) 337c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 338c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner /// NOTE: if we wanted to, this is where to detect integer MIN/MAX 339c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 340c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (CmpLHS == FalseVal && CmpRHS == TrueVal) { 341c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 342c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_EQ) 343c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 344c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? Y : X -> Y 345c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_NE) 346c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 347c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner /// NOTE: if we wanted to, this is where to detect integer MIN/MAX 348c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 349c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Changed ? &SI : 0; 350c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 351c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 352c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 353c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a 354c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// PHI node (but the two may be in different blocks). See if the true/false 355c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// values (V) are live in all of the predecessor blocks of the PHI. For 356c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// example, cases like this cannot be mapped: 357c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 358c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// X = phi [ C1, BB1], [C2, BB2] 359c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Y = add 360c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Z = select X, Y, 0 361c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 362c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// because Y is not live in BB1/BB2. 363c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 364c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool CanSelectOperandBeMappingIntoPredBlock(const Value *V, 365c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const SelectInst &SI) { 366c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If the value is a non-instruction value like a constant or argument, it 367c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can always be mapped. 368c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const Instruction *I = dyn_cast<Instruction>(V); 369c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (I == 0) return true; 370c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 371c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If V is a PHI node defined in the same block as the condition PHI, we can 372c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // map the arguments. 373c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const PHINode *CondPHI = cast<PHINode>(SI.getCondition()); 374c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 375c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (const PHINode *VP = dyn_cast<PHINode>(I)) 376c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (VP->getParent() == CondPHI->getParent()) 377c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 378c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 379c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise, if the PHI and select are defined in the same block and if V is 380c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // defined in a different block, then we can transform it. 381c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI.getParent() == CondPHI->getParent() && 382c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner I->getParent() != CondPHI->getParent()) 383c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 384c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 385c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise we have a 'hard' case and we can't tell without doing more 386c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // detailed dominator based analysis, punt. 387c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 388c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 389c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 390c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSPFofSPF - We have an SPF (e.g. a min or max) of an SPF of the form: 391c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// SPF2(SPF1(A, B), C) 392c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSPFofSPF(Instruction *Inner, 393c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF1, 394c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *A, Value *B, 395c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction &Outer, 396c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF2, Value *C) { 397c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C == A || C == B) { 398c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(A, B), B) -> MAX(A, B) 399c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 400c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SPF1 == SPF2) 401c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, Inner); 402c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 403c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 404c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 405c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) || 406c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) || 407c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) || 408c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN)) 409c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, C); 410c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 411c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 412c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: MIN(MIN(A, 23), 97) 413c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 414c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 415c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 416c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 417c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 418c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 419c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInst(SelectInst &SI) { 420c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CondVal = SI.getCondition(); 421c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 422c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 423c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 424c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select true, X, Y -> X 425c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select false, X, Y -> Y 426c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(CondVal)) 427c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, C->getZExtValue() ? TrueVal : FalseVal); 428c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 429c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, X, X -> X 430c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TrueVal == FalseVal) 431c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 432c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 433c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (isa<UndefValue>(TrueVal)) // select C, undef, X -> X 434c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 435c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X 436c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 437c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (isa<UndefValue>(CondVal)) { // select undef, X, Y -> X or Y 438c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (isa<Constant>(TrueVal)) 439c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 440c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else 441c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 442c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 443c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 44411acaa374cdcebb161bf0de5f244265d78a749c1Benjamin Kramer if (SI.getType()->isInteger(1)) { 445c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(TrueVal)) { 446c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue()) { 447c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, true, C --> A = or B, C 448c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 449c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 450c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, false, C --> A = and !B, C 451c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NotCond = 452c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, 453c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner "not."+CondVal->getName()), SI); 454c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(NotCond, FalseVal); 455c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 456c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) { 457c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue() == false) { 458c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, C, false --> A = and B, C 459c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 460c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 461c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, C, true --> A = or !B, C 462c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NotCond = 463c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, 464c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner "not."+CondVal->getName()), SI); 465c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(NotCond, TrueVal); 466c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 467c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 468c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 469c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, b, a -> a&b 470c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, a, b -> a|b 471c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CondVal == TrueVal) 472c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 473c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else if (CondVal == FalseVal) 474c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 475c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 476c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 477c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Selecting between two integer constants? 478c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal)) 479c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) { 480c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, 1, 0 -> zext C to int 481abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->getValue() == 1) 482abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(CondVal, SI.getType()); 483abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 484abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, -1, 0 -> sext C to int 485abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->isAllOnesValue()) 486abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(CondVal, SI.getType()); 487abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 488abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, 1 -> zext !C to int 489abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->getValue() == 1) { 490abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 491abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(NotCond, SI.getType()); 492c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 493c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 494abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, -1 -> sext !C to int 495abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->isAllOnesValue()) { 496abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 497abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(NotCond, SI.getType()); 498abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner } 499abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 500c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition())) { 501c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If one of the constants is zero (we know they can't both be) and we 502c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // have an icmp instruction with zero, and we have an 'and' with the 503c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // non-constant value, eliminate this whole mess. This corresponds to 504c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // cases like this: ((X & 27) ? 27 : 0) 505c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TrueValC->isZero() || FalseValC->isZero()) 506c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (IC->isEquality() && isa<ConstantInt>(IC->getOperand(1)) && 507c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner cast<Constant>(IC->getOperand(1))->isNullValue()) 508c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *ICA = dyn_cast<Instruction>(IC->getOperand(0))) 509c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICA->getOpcode() == Instruction::And && 510c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner isa<ConstantInt>(ICA->getOperand(1)) && 511c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (ICA->getOperand(1) == TrueValC || 512c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICA->getOperand(1) == FalseValC) && 513c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner cast<ConstantInt>(ICA->getOperand(1))->getValue().isPowerOf2()) { 514c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Okay, now we know that everything is set up, we just don't 515c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // know whether we have a icmp_ne or icmp_eq and whether the 516c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // true or false val is the zero. 517c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool ShouldNotVal = !TrueValC->isZero(); 518c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE; 519c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *V = ICA; 520c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ShouldNotVal) 521abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner V = Builder->CreateXor(V, ICA->getOperand(1)); 522c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, V); 523c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 524c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 525c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 526c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 527c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 528c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) { 529c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) { 530c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 531c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 532c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // This is not safe in general for floating point: 533c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 534c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 535c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 536c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 537c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 538c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 539c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 540c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 541c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 542c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? X : Y -> X 543c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_ONE) 544c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 545c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 546c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 547c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){ 548c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 549c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 550c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // This is not safe in general for floating point: 551c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 552c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 553c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 554c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 555c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 556c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 557c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 558c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 559c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 560c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? Y : X -> Y 561c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_ONE) 562c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 563c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 564c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 565c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect ABS 566c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 567c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 568c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 569c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal)) 570c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *Result = visitSelectInstWithICmp(SI, ICI)) 571c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Result; 572c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 573c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TI = dyn_cast<Instruction>(TrueVal)) 574c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FI = dyn_cast<Instruction>(FalseVal)) 575c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->hasOneUse() && FI->hasOneUse()) { 576c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *AddOp = 0, *SubOp = 0; 577c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 578c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z)) 579c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOpcode() == FI->getOpcode()) 580c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *IV = FoldSelectOpOp(SI, TI, FI)) 581c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return IV; 582c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 583c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y))). This is 584c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // even legal for FP. 585c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((TI->getOpcode() == Instruction::Sub && 586c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::Add) || 587c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (TI->getOpcode() == Instruction::FSub && 588c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::FAdd)) { 589c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = FI; SubOp = TI; 590c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((FI->getOpcode() == Instruction::Sub && 591c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::Add) || 592c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (FI->getOpcode() == Instruction::FSub && 593c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::FAdd)) { 594c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = TI; SubOp = FI; 595c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 596c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 597c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp) { 598c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OtherAddOp = 0; 599c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SubOp->getOperand(0) == AddOp->getOperand(0)) { 600c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(1); 601c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) { 602c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(0); 603c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 604c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 605c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OtherAddOp) { 606c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // So at this point we know we have (Y -> OtherAddOp): 607c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, (add X, Y), (sub X, Z) 608c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NegVal; // Compute -Z 609c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Constant *C = dyn_cast<Constant>(SubOp->getOperand(1))) { 610c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NegVal = ConstantExpr::getNeg(C); 611c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 612c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NegVal = InsertNewInstBefore( 613c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner BinaryOperator::CreateNeg(SubOp->getOperand(1), 614c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner "tmp"), SI); 615c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 616c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 617c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewTrueOp = OtherAddOp; 618c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewFalseOp = NegVal; 619c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp != TI) 620c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(NewTrueOp, NewFalseOp); 621c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = 622c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst::Create(CondVal, NewTrueOp, 623c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewFalseOp, SI.getName() + ".p"); 624c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 625c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel = InsertNewInstBefore(NewSel, SI); 626c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel); 627c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 628c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 629c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 630c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 631c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into one of our operands. 632c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI.getType()->isInteger()) { 633c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FoldI = FoldSelectIntoOp(SI, TrueVal, FalseVal)) 634c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return FoldI; 635c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 636c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(a, b), a) -> MAX(a, b) 637c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 638c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 639c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 640c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *LHS, *RHS, *LHS2, *RHS2; 641c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF = MatchSelectPattern(&SI, LHS, RHS)) { 642c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(LHS, LHS2, RHS2)) 643c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2, 644c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, RHS)) 645c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 646c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(RHS, LHS2, RHS2)) 647c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2, 648c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, LHS)) 649c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 650c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 651c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 652c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO. 653c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(-X) -> ABS(X) 654c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(ABS(X)) -> ABS(X) 655c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 656c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 657c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into a phi node if the condition is a select. 658c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (isa<PHINode>(SI.getCondition())) 659c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // The true/false values have to be live in the PHI predecessor's blocks. 660c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CanSelectOperandBeMappingIntoPredBlock(TrueVal, SI) && 661c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CanSelectOperandBeMappingIntoPredBlock(FalseVal, SI)) 662c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *NV = FoldOpIntoPhi(SI)) 663c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return NV; 664c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 665c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator::isNot(CondVal)) { 666c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(0, BinaryOperator::getNotArgument(CondVal)); 667c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, FalseVal); 668c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, TrueVal); 669c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return &SI; 670c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 671c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 672c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 673c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 674