119304Speter//===-- 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
19namespace llvm {
20class Value;
21class 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
40bool isCheckForZeroAndMulWithOverflow(Value *Op0, Value *Op1, bool IsAnd,
41                                      Use *&Y);
42bool isCheckForZeroAndMulWithOverflow(Value *Op0, Value *Op1, bool IsAnd);
43} // end namespace llvm
44
45#endif
46