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 | |