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 namespace llvm { 18 class Use; 19 class Value; 20 21 /// Match one of the patterns up to the select/logic op: 22 /// %Op0 = icmp ne i4 %X, 0 23 /// %Agg = call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %Y) 24 /// %Op1 = extractvalue { i4, i1 } %Agg, 1 25 /// %ret = select i1 %Op0, i1 %Op1, i1 false / %ret = and i1 %Op0, %Op1 26 /// 27 /// %Op0 = icmp eq i4 %X, 0 28 /// %Agg = call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %Y) 29 /// %NotOp1 = extractvalue { i4, i1 } %Agg, 1 30 /// %Op1 = xor i1 %NotOp1, true 31 /// %ret = select i1 %Op0, i1 true, i1 %Op1 / %ret = or i1 %Op0, %Op1 32 /// 33 /// Callers are expected to align that with the operands of the select/logic. 34 /// IsAnd is set to true if the Op0 and Op1 are used as the first pattern. 35 /// If Op0 and Op1 match one of the patterns above, return true and fill Y's 36 /// use. 37 38 bool isCheckForZeroAndMulWithOverflow(Value *Op0, Value *Op1, bool IsAnd, 39 Use *&Y); 40 bool isCheckForZeroAndMulWithOverflow(Value *Op0, Value *Op1, bool IsAnd); 41 } // end namespace llvm 42 43 #endif 44