1*fe6060f1SDimitry Andric //==-- OverflowInstAnalysis.cpp - Utils to fold overflow insts ----*- C++ -*-=// 2*fe6060f1SDimitry Andric // 3*fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*fe6060f1SDimitry Andric // 7*fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 8*fe6060f1SDimitry Andric // 9*fe6060f1SDimitry Andric // This file holds routines to help analyse overflow instructions 10*fe6060f1SDimitry Andric // and fold them into constants or other overflow instructions 11*fe6060f1SDimitry Andric // 12*fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 13*fe6060f1SDimitry Andric 14*fe6060f1SDimitry Andric #include "llvm/Analysis/OverflowInstAnalysis.h" 15*fe6060f1SDimitry Andric #include "llvm/IR/Constants.h" 16*fe6060f1SDimitry Andric #include "llvm/IR/Instructions.h" 17*fe6060f1SDimitry Andric #include "llvm/IR/PatternMatch.h" 18*fe6060f1SDimitry Andric 19*fe6060f1SDimitry Andric using namespace llvm; 20*fe6060f1SDimitry Andric using namespace llvm::PatternMatch; 21*fe6060f1SDimitry Andric 22*fe6060f1SDimitry Andric bool llvm::isCheckForZeroAndMulWithOverflow(Value *Op0, Value *Op1, bool IsAnd, 23*fe6060f1SDimitry Andric Use *&Y) { 24*fe6060f1SDimitry Andric ICmpInst::Predicate Pred; 25*fe6060f1SDimitry Andric Value *X, *NotOp1; 26*fe6060f1SDimitry Andric int XIdx; 27*fe6060f1SDimitry Andric IntrinsicInst *II; 28*fe6060f1SDimitry Andric 29*fe6060f1SDimitry Andric if (!match(Op0, m_ICmp(Pred, m_Value(X), m_Zero()))) 30*fe6060f1SDimitry Andric return false; 31*fe6060f1SDimitry Andric 32*fe6060f1SDimitry Andric /// %Agg = call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %???) 33*fe6060f1SDimitry Andric /// %V = extractvalue { i4, i1 } %Agg, 1 34*fe6060f1SDimitry Andric auto matchMulOverflowCheck = [X, &II, &XIdx](Value *V) { 35*fe6060f1SDimitry Andric auto *Extract = dyn_cast<ExtractValueInst>(V); 36*fe6060f1SDimitry Andric // We should only be extracting the overflow bit. 37*fe6060f1SDimitry Andric if (!Extract || !Extract->getIndices().equals(1)) 38*fe6060f1SDimitry Andric return false; 39*fe6060f1SDimitry Andric 40*fe6060f1SDimitry Andric II = dyn_cast<IntrinsicInst>(Extract->getAggregateOperand()); 41*fe6060f1SDimitry Andric if (!II || 42*fe6060f1SDimitry Andric !match(II, m_CombineOr(m_Intrinsic<Intrinsic::umul_with_overflow>(), 43*fe6060f1SDimitry Andric m_Intrinsic<Intrinsic::smul_with_overflow>()))) 44*fe6060f1SDimitry Andric return false; 45*fe6060f1SDimitry Andric 46*fe6060f1SDimitry Andric if (II->getArgOperand(0) == X) 47*fe6060f1SDimitry Andric XIdx = 0; 48*fe6060f1SDimitry Andric else if (II->getArgOperand(1) == X) 49*fe6060f1SDimitry Andric XIdx = 1; 50*fe6060f1SDimitry Andric else 51*fe6060f1SDimitry Andric return false; 52*fe6060f1SDimitry Andric return true; 53*fe6060f1SDimitry Andric }; 54*fe6060f1SDimitry Andric 55*fe6060f1SDimitry Andric bool Matched = 56*fe6060f1SDimitry Andric (IsAnd && Pred == ICmpInst::Predicate::ICMP_NE && 57*fe6060f1SDimitry Andric matchMulOverflowCheck(Op1)) || 58*fe6060f1SDimitry Andric (!IsAnd && Pred == ICmpInst::Predicate::ICMP_EQ && 59*fe6060f1SDimitry Andric match(Op1, m_Not(m_Value(NotOp1))) && matchMulOverflowCheck(NotOp1)); 60*fe6060f1SDimitry Andric 61*fe6060f1SDimitry Andric if (!Matched) 62*fe6060f1SDimitry Andric return false; 63*fe6060f1SDimitry Andric 64*fe6060f1SDimitry Andric Y = &II->getArgOperandUse(!XIdx); 65*fe6060f1SDimitry Andric return true; 66*fe6060f1SDimitry Andric } 67*fe6060f1SDimitry Andric 68*fe6060f1SDimitry Andric bool llvm::isCheckForZeroAndMulWithOverflow(Value *Op0, Value *Op1, 69*fe6060f1SDimitry Andric bool IsAnd) { 70*fe6060f1SDimitry Andric Use *Y; 71*fe6060f1SDimitry Andric return isCheckForZeroAndMulWithOverflow(Op0, Op1, IsAnd, Y); 72*fe6060f1SDimitry Andric }