1 //===-- OverflowInstAnalysis.h - Utils to fold overflow insts ----*- C++ -*-==// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file holds routines to help analyse overflow instructions 10 // and fold them into constants or other overflow instructions 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_ANALYSIS_OVERFLOWINSTANALYSIS_H 15 #define LLVM_ANALYSIS_OVERFLOWINSTANALYSIS_H 16 17 #include "llvm/IR/InstrTypes.h" 18 19 namespace llvm { 20 class Value; 21 class Use; 22 23 /// Match one of the patterns up to the select/logic op: 24 /// %Op0 = icmp ne i4 %X, 0 25 /// %Agg = call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %Y) 26 /// %Op1 = extractvalue { i4, i1 } %Agg, 1 27 /// %ret = select i1 %Op0, i1 %Op1, i1 false / %ret = and i1 %Op0, %Op1 28 /// 29 /// %Op0 = icmp eq i4 %X, 0 30 /// %Agg = call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %Y) 31 /// %NotOp1 = extractvalue { i4, i1 } %Agg, 1 32 /// %Op1 = xor i1 %NotOp1, true 33 /// %ret = select i1 %Op0, i1 true, i1 %Op1 / %ret = or i1 %Op0, %Op1 34 /// 35 /// Callers are expected to align that with the operands of the select/logic. 36 /// IsAnd is set to true if the Op0 and Op1 are used as the first pattern. 37 /// If Op0 and Op1 match one of the patterns above, return true and fill Y's 38 /// use. 39 40 bool isCheckForZeroAndMulWithOverflow(Value *Op0, Value *Op1, bool IsAnd, 41 Use *&Y); 42 bool isCheckForZeroAndMulWithOverflow(Value *Op0, Value *Op1, bool IsAnd); 43 } // end namespace llvm 44 45 #endif 46