InstCombineSelect.cpp revision 047542669a20505fc7c5f2d93caa5610aa3db2c5
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; 27c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 28c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition()); 29c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI == 0) return SPF_UNKNOWN; 30c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 31c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner LHS = ICI->getOperand(0); 32c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner RHS = ICI->getOperand(1); 33c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 34c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // (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 } 49c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 50c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // (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 } 65c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 66c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: (X > 4) ? X : 5 --> (X >= 5) ? X : 5 --> MAX(X, 5) 67c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 68c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return SPF_UNKNOWN; 69c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 70c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 71c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 72c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableOperands - We want to turn code that looks like this: 73c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = or %A, %B 74c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = select %cond, %C, %A 75c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// into: 76c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = select %cond, %B, 0 77c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = or %A, %C 78c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 79c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Assuming that the specified instruction is an operand to the select, return 80c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// a bitmask indicating which operands of this instruction are foldable if they 81c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// equal the other incoming value of the select. 82c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 83c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic unsigned GetSelectFoldableOperands(Instruction *I) { 84c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 85c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 86c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 87c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 88c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 89c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 90c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 3; // Can fold through either operand. 91c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: // Can only fold on the amount subtracted. 92c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: // Can only fold on the shift amount. 93c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 94c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 95c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 1; 96c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: 97c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // Cannot fold 98c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 99c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 100c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 101c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableConstant - For the same transformation as the previous 102c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// function, return the identity constant that goes into the select. 103c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic Constant *GetSelectFoldableConstant(Instruction *I) { 104c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 105c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: llvm_unreachable("This cannot happen!"); 106c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 107c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: 108c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 109c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 110c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: 111c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 112c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 113c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getNullValue(I->getType()); 114c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 115c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getAllOnesValue(I->getType()); 116c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 117c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ConstantInt::get(I->getType(), 1); 118c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 119c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 120c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 121c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectOpOp - Here we have (select c, TI, FI), and we know that TI and FI 122c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// have the same opcode and only one use each. Try to simplify this. 123c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectOpOp(SelectInst &SI, Instruction *TI, 124c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *FI) { 125c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getNumOperands() == 1) { 126c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If this is a non-volatile load or a cast from the same type, 127c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // merge. 128c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->isCast()) { 129c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0)->getType() != FI->getOperand(0)->getType()) 130c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 131c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 132c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // unknown unary op. 133c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 134c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 135c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Fold this by inserting a select from the input values. 136c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *NewSI = SelectInst::Create(SI.getCondition(), TI->getOperand(0), 137c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOperand(0), SI.getName()+".v"); 138c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSI, SI); 139c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI, 140c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getType()); 141c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 142c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 143c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Only handle binary operators here. 144c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<BinaryOperator>(TI)) 145c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 146c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 147c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Figure out if the operations have any operands in common. 148c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *MatchOp, *OtherOpT, *OtherOpF; 149c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool MatchIsOpZero; 150c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0) == FI->getOperand(0)) { 151c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 152c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 153c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 154c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 155c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(1)) { 156c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 157c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 158c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 159c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = false; 160c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (!TI->isCommutative()) { 161c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 162c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(0) == FI->getOperand(1)) { 163c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 164c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 165c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 166c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 167c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(0)) { 168c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 169c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 170c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 171c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 172c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 173c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 174c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 175c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 176c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If we reach here, they do have operations in common. 177c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *NewSI = SelectInst::Create(SI.getCondition(), OtherOpT, 178c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF, SI.getName()+".v"); 179c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSI, SI); 180c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 181c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TI)) { 182c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (MatchIsOpZero) 183c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), MatchOp, NewSI); 184c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else 185c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp); 186c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 187c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Shouldn't get here"); 188c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 189c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 190c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 191c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool isSelect01(Constant *C1, Constant *C2) { 192c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C1I = dyn_cast<ConstantInt>(C1); 193c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C1I) 194c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 195c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C2I = dyn_cast<ConstantInt>(C2); 196c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C2I) 197c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 198c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return (C1I->isZero() || C1I->isOne()) && (C2I->isZero() || C2I->isOne()); 199c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 200c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 201c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectIntoOp - Try fold the select into one of the operands to 202c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// facilitate further optimization. 203c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal, 204c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal) { 205c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See the comment above GetSelectFoldableOperands for a description of the 206c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // transformation we are doing here. 207c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) { 208c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TVI->hasOneUse() && TVI->getNumOperands() == 2 && 209c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(FalseVal)) { 210c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(TVI)) { 211c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 212c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && FalseVal == TVI->getOperand(0)) { 213c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 214c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) { 215c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 216c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 217c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 218c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 219c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(TVI); 220c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = TVI->getOperand(2-OpToFold); 221c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 222c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // between 0 and 1. 223c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 224c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = SelectInst::Create(SI.getCondition(), OOp, C); 225c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSel, SI); 226c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(TVI); 227c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TVI)) 228c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), FalseVal, NewSel); 229c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Unknown instruction!!"); 230c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 231c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 232c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 233c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 234c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 235c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 236c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) { 237c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FVI->hasOneUse() && FVI->getNumOperands() == 2 && 238c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(TrueVal)) { 239c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(FVI)) { 240c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 241c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && TrueVal == FVI->getOperand(0)) { 242c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 243c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) { 244c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 245c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 246c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 247c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 248c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(FVI); 249c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = FVI->getOperand(2-OpToFold); 250c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 251c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // between 0 and 1. 252c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 253c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = SelectInst::Create(SI.getCondition(), C, OOp); 254c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSel, SI); 255c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(FVI); 256c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(FVI)) 257c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), TrueVal, NewSel); 258c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Unknown instruction!!"); 259c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 260c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 261c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 262c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 263c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 264c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 265c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 266c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 267c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 268c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// visitSelectInstWithICmp - Visit a SelectInst that has an 269c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// ICmpInst as its first operand. 270c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 271c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI, 272c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI) { 273c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool Changed = false; 274c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst::Predicate Pred = ICI->getPredicate(); 275c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpLHS = ICI->getOperand(0); 276c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpRHS = ICI->getOperand(1); 277c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 278c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 279c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 280c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Check cases where the comparison is with a constant that 281c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can be adjusted to fit the min/max idiom. We may edit ICI in 282c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // place here, so make sure the select is the only user. 283c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI->hasOneUse()) 284c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(CmpRHS)) { 285c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (Pred) { 286c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: break; 287c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 288c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: { 289c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X < MIN ? T : F --> F 290c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CI->isMinValue(Pred == ICmpInst::ICMP_SLT)) 291c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 292c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X < C ? X : C-1 --> X > C-1 ? C-1 : X 293c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *AdjustedRHS = 294c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt::get(CI->getContext(), CI->getValue()-1); 295c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 296c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) { 297c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Pred = ICmpInst::getSwappedPredicate(Pred); 298c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CmpRHS = AdjustedRHS; 299c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(FalseVal, TrueVal); 300c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setPredicate(Pred); 301c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setOperand(1, CmpRHS); 302c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, TrueVal); 303c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, FalseVal); 304c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Changed = true; 305c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 306c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 307c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 308c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 309c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: { 310c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > MAX ? T : F --> F 311c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CI->isMaxValue(Pred == ICmpInst::ICMP_SGT)) 312c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 313c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > C ? X : C+1 --> X < C+1 ? C+1 : X 314c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *AdjustedRHS = 315c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt::get(CI->getContext(), CI->getValue()+1); 316c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 317c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) { 318c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Pred = ICmpInst::getSwappedPredicate(Pred); 319c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CmpRHS = AdjustedRHS; 320c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(FalseVal, TrueVal); 321c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setPredicate(Pred); 322c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setOperand(1, CmpRHS); 323c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, TrueVal); 324c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, FalseVal); 325c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Changed = true; 326c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 327c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 328c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 329c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 330c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 331c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 332c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CmpLHS == TrueVal && CmpRHS == FalseVal) { 333c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 334c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_EQ) 335c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 336c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? X : Y -> X 337c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_NE) 338c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 339c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner /// NOTE: if we wanted to, this is where to detect integer MIN/MAX 340c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 341c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (CmpLHS == FalseVal && CmpRHS == TrueVal) { 342c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 343c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_EQ) 344c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 345c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? Y : X -> Y 346c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_NE) 347c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 348c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner /// NOTE: if we wanted to, this is where to detect integer MIN/MAX 349c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 350c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Changed ? &SI : 0; 351c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 352c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 353c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 354c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a 355c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// PHI node (but the two may be in different blocks). See if the true/false 356c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// values (V) are live in all of the predecessor blocks of the PHI. For 357c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// example, cases like this cannot be mapped: 358c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 359c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// X = phi [ C1, BB1], [C2, BB2] 360c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Y = add 361c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Z = select X, Y, 0 362c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 363c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// because Y is not live in BB1/BB2. 364c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 365c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool CanSelectOperandBeMappingIntoPredBlock(const Value *V, 366c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const SelectInst &SI) { 367c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If the value is a non-instruction value like a constant or argument, it 368c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can always be mapped. 369c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const Instruction *I = dyn_cast<Instruction>(V); 370c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (I == 0) return true; 371c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 372c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If V is a PHI node defined in the same block as the condition PHI, we can 373c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // map the arguments. 374c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const PHINode *CondPHI = cast<PHINode>(SI.getCondition()); 375c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 376c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (const PHINode *VP = dyn_cast<PHINode>(I)) 377c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (VP->getParent() == CondPHI->getParent()) 378c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 379c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 380c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise, if the PHI and select are defined in the same block and if V is 381c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // defined in a different block, then we can transform it. 382c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI.getParent() == CondPHI->getParent() && 383c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner I->getParent() != CondPHI->getParent()) 384c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 385c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 386c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise we have a 'hard' case and we can't tell without doing more 387c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // detailed dominator based analysis, punt. 388c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 389c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 390c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 391c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSPFofSPF - We have an SPF (e.g. a min or max) of an SPF of the form: 392c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// SPF2(SPF1(A, B), C) 393c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSPFofSPF(Instruction *Inner, 394c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF1, 395c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *A, Value *B, 396c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction &Outer, 397c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF2, Value *C) { 398c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C == A || C == B) { 399c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(A, B), B) -> MAX(A, B) 400c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 401c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SPF1 == SPF2) 402c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, Inner); 403c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 404c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 405c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 406c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) || 407c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) || 408c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) || 409c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN)) 410c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, C); 411c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 412c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 413c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: MIN(MIN(A, 23), 97) 414c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 415c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 416c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 417c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 418c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 419c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 420c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInst(SelectInst &SI) { 421c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CondVal = SI.getCondition(); 422c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 423c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 424c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 425047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal, TD)) 426047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return ReplaceInstUsesWith(SI, V); 427c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 428b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy(1)) { 429c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(TrueVal)) { 430c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue()) { 431c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, true, C --> A = or B, C 432c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 433c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 434047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, false, C --> A = and !B, C 435047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner Value *NotCond = 436047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, 437047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner "not."+CondVal->getName()), SI); 438047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateAnd(NotCond, FalseVal); 439c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) { 440c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue() == false) { 441c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, C, false --> A = and B, C 442c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 443c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 444047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, C, true --> A = or !B, C 445047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner Value *NotCond = 446047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, 447047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner "not."+CondVal->getName()), SI); 448047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateOr(NotCond, TrueVal); 449c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 450c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 451c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, b, a -> a&b 452c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, a, b -> a|b 453c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CondVal == TrueVal) 454c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 455c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else if (CondVal == FalseVal) 456c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 457c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 458c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 459c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Selecting between two integer constants? 460c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal)) 461c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) { 462c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, 1, 0 -> zext C to int 463abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->getValue() == 1) 464abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(CondVal, SI.getType()); 465abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 466abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, -1, 0 -> sext C to int 467abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->isAllOnesValue()) 468abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(CondVal, SI.getType()); 469abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 470abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, 1 -> zext !C to int 471abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->getValue() == 1) { 472abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 473abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(NotCond, SI.getType()); 474c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 475c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 476abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, -1 -> sext !C to int 477abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->isAllOnesValue()) { 478abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 479abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(NotCond, SI.getType()); 480abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner } 481abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 482c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition())) { 483c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If one of the constants is zero (we know they can't both be) and we 484c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // have an icmp instruction with zero, and we have an 'and' with the 485c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // non-constant value, eliminate this whole mess. This corresponds to 486c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // cases like this: ((X & 27) ? 27 : 0) 487c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TrueValC->isZero() || FalseValC->isZero()) 488c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (IC->isEquality() && isa<ConstantInt>(IC->getOperand(1)) && 489c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner cast<Constant>(IC->getOperand(1))->isNullValue()) 490c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *ICA = dyn_cast<Instruction>(IC->getOperand(0))) 491c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICA->getOpcode() == Instruction::And && 492c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner isa<ConstantInt>(ICA->getOperand(1)) && 493c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (ICA->getOperand(1) == TrueValC || 494c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICA->getOperand(1) == FalseValC) && 495c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner cast<ConstantInt>(ICA->getOperand(1))->getValue().isPowerOf2()) { 496c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Okay, now we know that everything is set up, we just don't 497c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // know whether we have a icmp_ne or icmp_eq and whether the 498c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // true or false val is the zero. 499c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool ShouldNotVal = !TrueValC->isZero(); 500c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE; 501c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *V = ICA; 502c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ShouldNotVal) 503abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner V = Builder->CreateXor(V, ICA->getOperand(1)); 504c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, V); 505c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 506c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 507c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 508c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 509c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 510c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) { 511c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) { 512c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 513c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 514c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // This is not safe in general for floating point: 515c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 516c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 517c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 518c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 519c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 520c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 521c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 522c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 523c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 52421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? X : Y -> X 52521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 52621dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // This is not safe in general for floating point: 52721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 52821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 52921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 53021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 53121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 53221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 53321dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 534c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 53521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 536c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 537c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 538c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){ 539c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 540c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 541c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // This is not safe in general for floating point: 542c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 543c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 544c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 545c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 546c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 547c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 548c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 549c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 550c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 55121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? Y : X -> Y 55221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 55321dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // This is not safe in general for floating point: 55421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 55521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 55621dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 55721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 55821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 55921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 56021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 56121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman return ReplaceInstUsesWith(SI, TrueVal); 56221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 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. 632b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy()) { 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