InstCombineSelect.cpp revision 8d088bd1e4543e48f6e085885ab3a944fb3f2c93
11c22c80d71d7031fa1d4acb4d22dd91beb5487e6Chris Lattner//===- InstCombineSelect.cpp ----------------------------------------------===// 2c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 3c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// The LLVM Compiler Infrastructure 4c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 5c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// This file is distributed under the University of Illinois Open Source 6c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// License. See LICENSE.TXT for details. 7c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 8c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner//===----------------------------------------------------------------------===// 9c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 101c22c80d71d7031fa1d4acb4d22dd91beb5487e6Chris Lattner// This file implements the visitSelect function. 11c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner// 12c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner//===----------------------------------------------------------------------===// 13c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 14c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner#include "InstCombine.h" 15c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner#include "llvm/Support/PatternMatch.h" 16047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner#include "llvm/Analysis/InstructionSimplify.h" 17c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerusing namespace llvm; 18c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerusing namespace PatternMatch; 19c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 20c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// MatchSelectPattern - Pattern match integer [SU]MIN, [SU]MAX, and ABS idioms, 21c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// returning the kind and providing the out parameter results if we 22c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// successfully match. 23c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic SelectPatternFlavor 24c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerMatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) { 25c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *SI = dyn_cast<SelectInst>(V); 26c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI == 0) return SPF_UNKNOWN; 278d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 28c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI = dyn_cast<ICmpInst>(SI->getCondition()); 29c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI == 0) return SPF_UNKNOWN; 308d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 31c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner LHS = ICI->getOperand(0); 32c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner RHS = ICI->getOperand(1); 338d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 348d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // (icmp X, Y) ? X : Y 35c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI->getTrueValue() == ICI->getOperand(0) && 36c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI->getFalseValue() == ICI->getOperand(1)) { 37c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (ICI->getPredicate()) { 38c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: return SPF_UNKNOWN; // Equality. 39c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 40c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGE: return SPF_UMAX; 41c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: 42c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGE: return SPF_SMAX; 43c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 44c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULE: return SPF_UMIN; 45c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: 46c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLE: return SPF_SMIN; 47c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 48c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 498d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 508d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // (icmp X, Y) ? Y : X 51c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI->getTrueValue() == ICI->getOperand(1) && 52c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI->getFalseValue() == ICI->getOperand(0)) { 53c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (ICI->getPredicate()) { 54c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: return SPF_UNKNOWN; // Equality. 55c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 56c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGE: return SPF_UMIN; 57c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: 58c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGE: return SPF_SMIN; 59c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 60c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULE: return SPF_UMAX; 61c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: 62c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLE: return SPF_SMAX; 63c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 64c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 658d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 66c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: (X > 4) ? X : 5 --> (X >= 5) ? X : 5 --> MAX(X, 5) 678d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 68c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return SPF_UNKNOWN; 69c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 70c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 71c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 72c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableOperands - We want to turn code that looks like this: 73c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = or %A, %B 74c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = select %cond, %C, %A 75c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// into: 76c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %C = select %cond, %B, 0 77c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// %D = or %A, %C 78c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 79c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Assuming that the specified instruction is an operand to the select, return 80c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// a bitmask indicating which operands of this instruction are foldable if they 81c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// equal the other incoming value of the select. 82c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 83c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic unsigned GetSelectFoldableOperands(Instruction *I) { 84c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 85c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 86c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 87c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 88c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 89c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 90c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 3; // Can fold through either operand. 91c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: // Can only fold on the amount subtracted. 92c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: // Can only fold on the shift amount. 93c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 94c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 95c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 1; 96c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: 97c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // Cannot fold 98c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 99c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 100c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 101c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// GetSelectFoldableConstant - For the same transformation as the previous 102c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// function, return the identity constant that goes into the select. 103c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic Constant *GetSelectFoldableConstant(Instruction *I) { 104c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (I->getOpcode()) { 105c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: llvm_unreachable("This cannot happen!"); 106c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Add: 107c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Sub: 108c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Or: 109c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Xor: 110c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Shl: 111c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::LShr: 112c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::AShr: 113c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getNullValue(I->getType()); 114c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::And: 115c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Constant::getAllOnesValue(I->getType()); 116c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case Instruction::Mul: 117c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ConstantInt::get(I->getType(), 1); 118c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 119c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 120c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 121c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectOpOp - Here we have (select c, TI, FI), and we know that TI and FI 122c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// have the same opcode and only one use each. Try to simplify this. 123c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectOpOp(SelectInst &SI, Instruction *TI, 124c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *FI) { 125c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getNumOperands() == 1) { 126c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If this is a non-volatile load or a cast from the same type, 127c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // merge. 128c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->isCast()) { 129c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0)->getType() != FI->getOperand(0)->getType()) 130c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 131c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 132c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; // unknown unary op. 133c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 134c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 135c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Fold this by inserting a select from the input values. 136c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *NewSI = SelectInst::Create(SI.getCondition(), TI->getOperand(0), 137c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOperand(0), SI.getName()+".v"); 138c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSI, SI); 1398d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser return CastInst::Create(Instruction::CastOps(TI->getOpcode()), NewSI, 140c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getType()); 141c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 142c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 143c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Only handle binary operators here. 144c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<BinaryOperator>(TI)) 145c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 146c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 147c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Figure out if the operations have any operands in common. 148c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *MatchOp, *OtherOpT, *OtherOpF; 149c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool MatchIsOpZero; 150c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOperand(0) == FI->getOperand(0)) { 151c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 152c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 153c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 154c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 155c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(1)) { 156c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 157c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 158c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 159c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = false; 160c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (!TI->isCommutative()) { 161c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 162c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(0) == FI->getOperand(1)) { 163c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(0); 164c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(1); 165c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(0); 166c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 167c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (TI->getOperand(1) == FI->getOperand(0)) { 168c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchOp = TI->getOperand(1); 169c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpT = TI->getOperand(0); 170c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF = FI->getOperand(1); 171c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner MatchIsOpZero = true; 172c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 173c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 174c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 175c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 176c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If we reach here, they do have operations in common. 177c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst *NewSI = SelectInst::Create(SI.getCondition(), OtherOpT, 178c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherOpF, SI.getName()+".v"); 179c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSI, SI); 180c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 181c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TI)) { 182c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (MatchIsOpZero) 183c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), MatchOp, NewSI); 184c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else 185c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp); 186c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 187c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Shouldn't get here"); 188c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 189c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 190c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 191c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool isSelect01(Constant *C1, Constant *C2) { 192c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C1I = dyn_cast<ConstantInt>(C1); 193c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C1I) 194c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 195c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt *C2I = dyn_cast<ConstantInt>(C2); 196c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!C2I) 197c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 1984ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer if (!C1I->isZero() && !C2I->isZero()) // One side must be zero. 1994ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer return false; 2004ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer return C1I->isOne() || C1I->isAllOnesValue() || 2014ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer C2I->isOne() || C2I->isAllOnesValue(); 202c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 203c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 204c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSelectIntoOp - Try fold the select into one of the operands to 205c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// facilitate further optimization. 206c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSelectIntoOp(SelectInst &SI, Value *TrueVal, 207c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal) { 208c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See the comment above GetSelectFoldableOperands for a description of the 209c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // transformation we are doing here. 210c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TVI = dyn_cast<Instruction>(TrueVal)) { 211c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TVI->hasOneUse() && TVI->getNumOperands() == 2 && 212c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(FalseVal)) { 213c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(TVI)) { 214c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 215c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && FalseVal == TVI->getOperand(0)) { 216c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 217c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((SFO & 2) && FalseVal == TVI->getOperand(1)) { 218c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 219c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 220c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 221c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 222c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(TVI); 223c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = TVI->getOperand(2-OpToFold); 224c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 2254ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer // between 0, 1 and -1. 226c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 227c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = SelectInst::Create(SI.getCondition(), OOp, C); 228c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSel, SI); 229c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(TVI); 230c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TVI)) 231c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), FalseVal, NewSel); 232c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Unknown instruction!!"); 233c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 234c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 235c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 236c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 237c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 238c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 239c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FVI = dyn_cast<Instruction>(FalseVal)) { 240c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FVI->hasOneUse() && FVI->getNumOperands() == 2 && 241c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !isa<Constant>(TrueVal)) { 242c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (unsigned SFO = GetSelectFoldableOperands(FVI)) { 243c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner unsigned OpToFold = 0; 244c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SFO & 1) && TrueVal == FVI->getOperand(0)) { 245c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 1; 246c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((SFO & 2) && TrueVal == FVI->getOperand(1)) { 247c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OpToFold = 2; 248c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 249c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 250c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OpToFold) { 251c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *C = GetSelectFoldableConstant(FVI); 252c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OOp = FVI->getOperand(2-OpToFold); 253c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Avoid creating select between 2 constants unless it's selecting 2544ac19470dc26decba85f5bf4dd7e6edb54d77152Benjamin Kramer // between 0, 1 and -1. 255c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (!isa<Constant>(OOp) || isSelect01(C, cast<Constant>(OOp))) { 256c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = SelectInst::Create(SI.getCondition(), C, OOp); 257c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner InsertNewInstBefore(NewSel, SI); 258c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel->takeName(FVI); 259c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator *BO = dyn_cast<BinaryOperator>(FVI)) 260c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::Create(BO->getOpcode(), TrueVal, NewSel); 261c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner llvm_unreachable("Unknown instruction!!"); 262c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 263c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 264c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 265c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 266c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 267c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 268c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 269c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 270c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 271c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// visitSelectInstWithICmp - Visit a SelectInst that has an 272c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// ICmpInst as its first operand. 273c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 274c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI, 275c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst *ICI) { 276c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner bool Changed = false; 277c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICmpInst::Predicate Pred = ICI->getPredicate(); 278c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpLHS = ICI->getOperand(0); 279c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CmpRHS = ICI->getOperand(1); 280c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 281c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 282c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 283c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Check cases where the comparison is with a constant that 284c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can be adjusted to fit the min/max idiom. We may edit ICI in 285c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // place here, so make sure the select is the only user. 286c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICI->hasOneUse()) 287c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(CmpRHS)) { 288c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner switch (Pred) { 289c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner default: break; 290c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_ULT: 291c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SLT: { 292c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X < MIN ? T : F --> F 293c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CI->isMinValue(Pred == ICmpInst::ICMP_SLT)) 294c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 295c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X < C ? X : C-1 --> X > C-1 ? C-1 : X 296c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *AdjustedRHS = 297c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt::get(CI->getContext(), CI->getValue()-1); 298c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 299c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) { 300c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Pred = ICmpInst::getSwappedPredicate(Pred); 301c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CmpRHS = AdjustedRHS; 302c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(FalseVal, TrueVal); 303c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setPredicate(Pred); 304c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setOperand(1, CmpRHS); 305c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, TrueVal); 306c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, FalseVal); 307c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Changed = true; 308c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 309c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 310c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 311c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_UGT: 312c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner case ICmpInst::ICMP_SGT: { 313c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > MAX ? T : F --> F 314c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CI->isMaxValue(Pred == ICmpInst::ICMP_SGT)) 315c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 316c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // X > C ? X : C+1 --> X < C+1 ? C+1 : X 317c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Constant *AdjustedRHS = 318c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantInt::get(CI->getContext(), CI->getValue()+1); 319c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((CmpLHS == TrueVal && AdjustedRHS == FalseVal) || 320c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (CmpLHS == FalseVal && AdjustedRHS == TrueVal)) { 321c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Pred = ICmpInst::getSwappedPredicate(Pred); 322c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CmpRHS = AdjustedRHS; 323c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(FalseVal, TrueVal); 324c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setPredicate(Pred); 325c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ICI->setOperand(1, CmpRHS); 326c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, TrueVal); 327c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, FalseVal); 328c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Changed = true; 329c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 330c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner break; 331c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 332c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 333c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 334c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 3351db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // Transform (X >s -1) ? C1 : C2 --> ((X >>s 31) & (C2 - C1)) + C1 3361db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // and (X <s 0) ? C2 : C1 --> ((X >>s 31) & (C2 - C1)) + C1 3371db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // FIXME: Type and constness constraints could be lifted, but we have to 3381db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // watch code size carefully. We should consider xor instead of 3391db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // sub/add when we decide to do that. 3401db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (const IntegerType *Ty = dyn_cast<IntegerType>(CmpLHS->getType())) { 3411db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (TrueVal->getType() == Ty) { 3421db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (ConstantInt *Cmp = dyn_cast<ConstantInt>(CmpRHS)) { 3431db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer ConstantInt *C1 = NULL, *C2 = NULL; 3441db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (Pred == ICmpInst::ICMP_SGT && Cmp->isAllOnesValue()) { 3451db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C1 = dyn_cast<ConstantInt>(TrueVal); 3461db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C2 = dyn_cast<ConstantInt>(FalseVal); 3471db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } else if (Pred == ICmpInst::ICMP_SLT && Cmp->isNullValue()) { 3481db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C1 = dyn_cast<ConstantInt>(FalseVal); 3491db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer C2 = dyn_cast<ConstantInt>(TrueVal); 3501db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 3511db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (C1 && C2) { 3521db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // This shift results in either -1 or 0. 3531db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer Value *AShr = Builder->CreateAShr(CmpLHS, Ty->getBitWidth()-1); 3541db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 3551db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer // Check if we can express the operation with a single or. 3561db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer if (C2->isAllOnesValue()) 3571db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer return ReplaceInstUsesWith(SI, Builder->CreateOr(AShr, C1)); 3581db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 3591db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer Value *And = Builder->CreateAnd(AShr, C2->getValue()-C1->getValue()); 3601db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer return ReplaceInstUsesWith(SI, Builder->CreateAdd(And, C1)); 3611db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 3621db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 3631db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 3641db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer } 3651db071f0dae25d0c5a1af61ca71fa20d0a8e9370Benjamin Kramer 366c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CmpLHS == TrueVal && CmpRHS == FalseVal) { 367c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 368c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_EQ) 369c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 370c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? X : Y -> X 371c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_NE) 372c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 373c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner /// NOTE: if we wanted to, this is where to detect integer MIN/MAX 374c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 375c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (CmpLHS == FalseVal && CmpRHS == TrueVal) { 376c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 377c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_EQ) 378c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 379c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X != Y) ? Y : X -> Y 380c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Pred == ICmpInst::ICMP_NE) 381c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 382c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner /// NOTE: if we wanted to, this is where to detect integer MIN/MAX 383c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 384c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Changed ? &SI : 0; 385c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 386c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 387c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 388c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// CanSelectOperandBeMappingIntoPredBlock - SI is a select whose condition is a 389c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// PHI node (but the two may be in different blocks). See if the true/false 390c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// values (V) are live in all of the predecessor blocks of the PHI. For 391c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// example, cases like this cannot be mapped: 392c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 393c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// X = phi [ C1, BB1], [C2, BB2] 394c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Y = add 395c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// Z = select X, Y, 0 396c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 397c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// because Y is not live in BB1/BB2. 398c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// 399c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattnerstatic bool CanSelectOperandBeMappingIntoPredBlock(const Value *V, 400c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const SelectInst &SI) { 401c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If the value is a non-instruction value like a constant or argument, it 402c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // can always be mapped. 403c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const Instruction *I = dyn_cast<Instruction>(V); 404c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (I == 0) return true; 4058d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 406c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // If V is a PHI node defined in the same block as the condition PHI, we can 407c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // map the arguments. 408c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner const PHINode *CondPHI = cast<PHINode>(SI.getCondition()); 4098d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 410c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (const PHINode *VP = dyn_cast<PHINode>(I)) 411c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (VP->getParent() == CondPHI->getParent()) 412c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 4138d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 414c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise, if the PHI and select are defined in the same block and if V is 415c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // defined in a different block, then we can transform it. 416c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SI.getParent() == CondPHI->getParent() && 417c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner I->getParent() != CondPHI->getParent()) 418c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return true; 4198d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 420c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Otherwise we have a 'hard' case and we can't tell without doing more 421c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // detailed dominator based analysis, punt. 422c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return false; 423c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 424c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 425c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner/// FoldSPFofSPF - We have an SPF (e.g. a min or max) of an SPF of the form: 4268d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser/// SPF2(SPF1(A, B), C) 427c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::FoldSPFofSPF(Instruction *Inner, 428c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF1, 429c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *A, Value *B, 430c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction &Outer, 431c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectPatternFlavor SPF2, Value *C) { 432c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C == A || C == B) { 433c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(A, B), B) -> MAX(A, B) 434c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 435c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SPF1 == SPF2) 436c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, Inner); 4378d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 438c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 439c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 440c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((SPF1 == SPF_SMIN && SPF2 == SPF_SMAX) || 441c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_SMAX && SPF2 == SPF_SMIN) || 442c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMIN && SPF2 == SPF_UMAX) || 443c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (SPF1 == SPF_UMAX && SPF2 == SPF_UMIN)) 444c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(Outer, C); 445c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 4468d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 447c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO: MIN(MIN(A, 23), 97) 448c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 449c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 450c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 451c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 45220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// foldSelectICmpAnd - If one of the constants is zero (we know they can't 45320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// both be) and we have an icmp instruction with zero, and we have an 'and' 45420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// with the non-constant value and a power of two we can turn the select 45520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer/// into a shift on the result of the 'and'. 45620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramerstatic Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal, 45720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *FalseVal, 45820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer InstCombiner::BuilderTy *Builder) { 45920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition()); 46020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!IC || !IC->isEquality()) 46120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 46220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 46320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ConstantInt *C = dyn_cast<ConstantInt>(IC->getOperand(1))) 46420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!C->isZero()) 46520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 46620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 46720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *AndRHS; 46820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer Value *LHS = IC->getOperand(0); 46920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (LHS->getType() != SI.getType() || 47020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer !match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS)))) 47120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 47220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 4732f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // If both select arms are non-zero see if we have a select of the form 4742f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // 'x ? 2^n + C : C'. Then we can offset both arms by C, use the logic 4752f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // for 'x ? 2^n : 0' and fix the thing up at the end. 4762f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer ConstantInt *Offset = 0; 4772f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if (!TrueVal->isZero() && !FalseVal->isZero()) { 4782f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if ((TrueVal->getValue() - FalseVal->getValue()).isPowerOf2()) 4792f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer Offset = FalseVal; 4802f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer else if ((FalseVal->getValue() - TrueVal->getValue()).isPowerOf2()) 4812f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer Offset = TrueVal; 4822f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer else 4832f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer return 0; 4842f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer 4852f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // Adjust TrueVal and FalseVal to the offset. 4862f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer TrueVal = ConstantInt::get(Builder->getContext(), 4872f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer TrueVal->getValue() - Offset->getValue()); 4882f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer FalseVal = ConstantInt::get(Builder->getContext(), 4892f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer FalseVal->getValue() - Offset->getValue()); 4902f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer } 49120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 49220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Make sure the mask in the 'and' and one of the select arms is a power of 2. 49320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (!AndRHS->getValue().isPowerOf2() || 49420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer (!TrueVal->getValue().isPowerOf2() && 49520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer !FalseVal->getValue().isPowerOf2())) 49620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return 0; 49720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 49820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Determine which shift is needed to transform result of the 'and' into the 49920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // desired result. 50020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ConstantInt *ValC = !TrueVal->isZero() ? TrueVal : FalseVal; 50120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer unsigned ValZeros = ValC->getValue().logBase2(); 50220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer unsigned AndZeros = AndRHS->getValue().logBase2(); 50320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 50420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer Value *V = LHS; 50520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ValZeros > AndZeros) 50620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateShl(V, ValZeros - AndZeros); 50720e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer else if (ValZeros < AndZeros) 50820e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateLShr(V, AndZeros - ValZeros); 50920e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 51020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // Okay, now we know that everything is set up, we just don't know whether we 51120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer // have a icmp_ne or icmp_eq and whether the true or false val is the zero. 51220e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer bool ShouldNotVal = !TrueVal->isZero(); 51320e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer ShouldNotVal ^= IC->getPredicate() == ICmpInst::ICMP_NE; 51420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (ShouldNotVal) 51520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer V = Builder->CreateXor(V, ValC); 5162f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer 5172f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer // Apply an offset if needed. 5182f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer if (Offset) 5192f7228b80c6a129fa1d8eef8c3075085003d5b87Benjamin Kramer V = Builder->CreateAdd(V, Offset); 52020e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return V; 52120e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer} 522c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 523c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris LattnerInstruction *InstCombiner::visitSelectInst(SelectInst &SI) { 524c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *CondVal = SI.getCondition(); 525c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *TrueVal = SI.getTrueValue(); 526c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *FalseVal = SI.getFalseValue(); 527c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 528047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner if (Value *V = SimplifySelectInst(CondVal, TrueVal, FalseVal, TD)) 529047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return ReplaceInstUsesWith(SI, V); 530c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 531b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy(1)) { 532c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(TrueVal)) { 533c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue()) { 534c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, true, C --> A = or B, C 535c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 536c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 537047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, false, C --> A = and !B, C 538047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner Value *NotCond = 539047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, 540047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner "not."+CondVal->getName()), SI); 541047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateAnd(NotCond, FalseVal); 542c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (ConstantInt *C = dyn_cast<ConstantInt>(FalseVal)) { 543c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (C->getZExtValue() == false) { 544c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Change: A = select B, C, false --> A = and B, C 545c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 546c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 547047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner // Change: A = select B, C, true --> A = or !B, C 548047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner Value *NotCond = 549047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner InsertNewInstBefore(BinaryOperator::CreateNot(CondVal, 550047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner "not."+CondVal->getName()), SI); 551047542669a20505fc7c5f2d93caa5610aa3db2c5Chris Lattner return BinaryOperator::CreateOr(NotCond, TrueVal); 552c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 5538d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 554c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, b, a -> a&b 555c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select a, a, b -> a|b 556c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CondVal == TrueVal) 557c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateOr(CondVal, FalseVal); 558c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner else if (CondVal == FalseVal) 559c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return BinaryOperator::CreateAnd(CondVal, TrueVal); 560c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 561c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 562c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Selecting between two integer constants? 563c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *TrueValC = dyn_cast<ConstantInt>(TrueVal)) 564c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ConstantInt *FalseValC = dyn_cast<ConstantInt>(FalseVal)) { 565c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, 1, 0 -> zext C to int 566abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->getValue() == 1) 567abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(CondVal, SI.getType()); 568abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner 569abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, -1, 0 -> sext C to int 570abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (FalseValC->isZero() && TrueValC->isAllOnesValue()) 571abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(CondVal, SI.getType()); 5728d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 573abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, 1 -> zext !C to int 574abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->getValue() == 1) { 575abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 576abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new ZExtInst(NotCond, SI.getType()); 577c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 578c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 579abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner // select C, 0, -1 -> sext !C to int 580abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner if (TrueValC->isZero() && FalseValC->isAllOnesValue()) { 581abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner Value *NotCond = Builder->CreateNot(CondVal, "not."+CondVal->getName()); 582abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner return new SExtInst(NotCond, SI.getType()); 583abb992d6a3d2dc05d3f3c62a367ea8977a7dd070Chris Lattner } 58420e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer 58520e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer if (Value *V = foldSelectICmpAnd(SI, TrueValC, FalseValC, Builder)) 58620e3b4b380e949af32eeb4f184c51bfd62286f1aBenjamin Kramer return ReplaceInstUsesWith(SI, V); 587c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 588c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 589c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 590c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) { 591c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) { 592c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? X : Y -> Y 593c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 5948d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 595c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 596c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 597c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 598c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 599c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 600c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 601c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 602c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 603c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 60421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? X : Y -> X 60521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 6068d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 60721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 60821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 60921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 61021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 61121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 61221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 61321dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 614c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, TrueVal); 61521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 616c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 617c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 618c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (FCI->getOperand(0) == FalseVal && FCI->getOperand(1) == TrueVal){ 619c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Transform (X == Y) ? Y : X -> X 620c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (FCI->getPredicate() == FCmpInst::FCMP_OEQ) { 6218d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 622c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // consider X== -0, Y== +0. 623c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // It becomes safe if either operand is a nonzero constant. 624c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ConstantFP *CFPt, *CFPf; 625c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 626c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPt->getValueAPF().isZero()) || 627c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 628c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner !CFPf->getValueAPF().isZero())) 629c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return ReplaceInstUsesWith(SI, FalseVal); 630c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 63121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // Transform (X une Y) ? Y : X -> Y 63221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (FCI->getPredicate() == FCmpInst::FCMP_UNE) { 6338d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser // This is not safe in general for floating point: 63421dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // consider X== -0, Y== +0. 63521dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman // It becomes safe if either operand is a nonzero constant. 63621dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ConstantFP *CFPt, *CFPf; 63721dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman if (((CFPt = dyn_cast<ConstantFP>(TrueVal)) && 63821dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPt->getValueAPF().isZero()) || 63921dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman ((CFPf = dyn_cast<ConstantFP>(FalseVal)) && 64021dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman !CFPf->getValueAPF().isZero())) 64121dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman return ReplaceInstUsesWith(SI, TrueVal); 64221dc20cbd62e0b4617cad7df947318801eec81e6Dan Gohman } 643c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect MIN/MAX 644c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 645c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // NOTE: if we wanted to, this is where to detect ABS 646c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 647c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 648c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we are selecting two values based on a comparison of the two values. 649c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (ICmpInst *ICI = dyn_cast<ICmpInst>(CondVal)) 650c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *Result = visitSelectInstWithICmp(SI, ICI)) 651c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return Result; 652c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 653c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *TI = dyn_cast<Instruction>(TrueVal)) 654c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FI = dyn_cast<Instruction>(FalseVal)) 655c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->hasOneUse() && FI->hasOneUse()) { 656c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *AddOp = 0, *SubOp = 0; 657c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 658c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn (select C, (op X, Y), (op X, Z)) -> (op X, (select C, Y, Z)) 659c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (TI->getOpcode() == FI->getOpcode()) 660c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *IV = FoldSelectOpOp(SI, TI, FI)) 661c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return IV; 662c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 663c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // Turn select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y))). This is 664c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // even legal for FP. 665c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if ((TI->getOpcode() == Instruction::Sub && 666c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::Add) || 667c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (TI->getOpcode() == Instruction::FSub && 668c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner FI->getOpcode() == Instruction::FAdd)) { 669c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = FI; SubOp = TI; 670c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if ((FI->getOpcode() == Instruction::Sub && 671c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::Add) || 672c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner (FI->getOpcode() == Instruction::FSub && 673c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner TI->getOpcode() == Instruction::FAdd)) { 674c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner AddOp = TI; SubOp = FI; 675c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 676c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 677c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp) { 678c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *OtherAddOp = 0; 679c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SubOp->getOperand(0) == AddOp->getOperand(0)) { 680c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(1); 681c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else if (SubOp->getOperand(0) == AddOp->getOperand(1)) { 682c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner OtherAddOp = AddOp->getOperand(0); 683c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 684c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 685c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (OtherAddOp) { 686c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // So at this point we know we have (Y -> OtherAddOp): 687c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // select C, (add X, Y), (sub X, Z) 688c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NegVal; // Compute -Z 689c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Constant *C = dyn_cast<Constant>(SubOp->getOperand(1))) { 690c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NegVal = ConstantExpr::getNeg(C); 691f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen } else if (SI.getType()->isFloatingPointTy()) { 692f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen NegVal = InsertNewInstBefore( 693f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen BinaryOperator::CreateFNeg(SubOp->getOperand(1), 694f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen "tmp"), SI); 695c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } else { 696c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NegVal = InsertNewInstBefore( 697c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner BinaryOperator::CreateNeg(SubOp->getOperand(1), 698c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner "tmp"), SI); 699c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 700c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 701c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewTrueOp = OtherAddOp; 702c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *NewFalseOp = NegVal; 703c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (AddOp != TI) 704c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner std::swap(NewTrueOp, NewFalseOp); 705c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Instruction *NewSel = 706c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SelectInst::Create(CondVal, NewTrueOp, 707c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewFalseOp, SI.getName() + ".p"); 708c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 709c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner NewSel = InsertNewInstBefore(NewSel, SI); 710f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen if (SI.getType()->isFloatingPointTy()) 711f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen return BinaryOperator::CreateFAdd(SubOp->getOperand(0), NewSel); 712f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen else 713f514f5279043652a8ac915e8e3c176d53980a128Dale Johannesen return BinaryOperator::CreateAdd(SubOp->getOperand(0), NewSel); 714c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 715c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 716c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 717c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 718c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into one of our operands. 719b0bc6c361da9009e8414efde317d9bbff755f6c0Duncan Sands if (SI.getType()->isIntegerTy()) { 720c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *FoldI = FoldSelectIntoOp(SI, TrueVal, FalseVal)) 721c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return FoldI; 7228d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser 723c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MAX(a, b), a) -> MAX(a, b) 724c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MIN(a, b), a) -> MIN(a, b) 725c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MAX(MIN(a, b), a) -> a 726c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // MIN(MAX(a, b), a) -> a 727c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner Value *LHS, *RHS, *LHS2, *RHS2; 728c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF = MatchSelectPattern(&SI, LHS, RHS)) { 729c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(LHS, LHS2, RHS2)) 730c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2, 731c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, RHS)) 732c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 733c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (SelectPatternFlavor SPF2 = MatchSelectPattern(RHS, LHS2, RHS2)) 734c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *R = FoldSPFofSPF(cast<Instruction>(RHS),SPF2,LHS2,RHS2, 735c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI, SPF, LHS)) 736c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return R; 737c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 738c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 739c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // TODO. 740c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(-X) -> ABS(X) 741c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // ABS(ABS(X)) -> ABS(X) 742c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 743c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 744c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // See if we can fold the select into a phi node if the condition is a select. 7458d088bd1e4543e48f6e085885ab3a944fb3f2c93Tobias Grosser if (isa<PHINode>(SI.getCondition())) 746c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner // The true/false values have to be live in the PHI predecessor's blocks. 747c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (CanSelectOperandBeMappingIntoPredBlock(TrueVal, SI) && 748c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner CanSelectOperandBeMappingIntoPredBlock(FalseVal, SI)) 749c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (Instruction *NV = FoldOpIntoPhi(SI)) 750c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return NV; 751c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 752c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner if (BinaryOperator::isNot(CondVal)) { 753c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(0, BinaryOperator::getNotArgument(CondVal)); 754c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(1, FalseVal); 755c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner SI.setOperand(2, TrueVal); 756c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return &SI; 757c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner } 758c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner 759c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner return 0; 760c6334b97e1de7c7c67c7279bdc44eb99ea65c78cChris Lattner} 761