1 | //===- FPEnv.h ---- FP Environment ------------------------------*- 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 | /// @file |
10 | /// This file contains the declarations of entities that describe floating |
11 | /// point environment and related functions. |
12 | // |
13 | //===----------------------------------------------------------------------===// |
14 | |
15 | #ifndef LLVM_IR_FPENV_H |
16 | #define LLVM_IR_FPENV_H |
17 | |
18 | #include "llvm/ADT/FloatingPointMode.h" |
19 | #include "llvm/IR/FMF.h" |
20 | #include <optional> |
21 | |
22 | namespace llvm { |
23 | class StringRef; |
24 | |
25 | namespace Intrinsic { |
26 | typedef unsigned ID; |
27 | } |
28 | |
29 | class Instruction; |
30 | |
31 | namespace fp { |
32 | |
33 | /// Exception behavior used for floating point operations. |
34 | /// |
35 | /// Each of these values correspond to some metadata argument value of a |
36 | /// constrained floating point intrinsic. See the LLVM Language Reference Manual |
37 | /// for details. |
38 | enum ExceptionBehavior : uint8_t { |
39 | ebIgnore, ///< This corresponds to "fpexcept.ignore". |
40 | ebMayTrap, ///< This corresponds to "fpexcept.maytrap". |
41 | ebStrict ///< This corresponds to "fpexcept.strict". |
42 | }; |
43 | |
44 | } |
45 | |
46 | /// Returns a valid RoundingMode enumerator when given a string |
47 | /// that is valid as input in constrained intrinsic rounding mode |
48 | /// metadata. |
49 | std::optional<RoundingMode> convertStrToRoundingMode(StringRef); |
50 | |
51 | /// For any RoundingMode enumerator, returns a string valid as input in |
52 | /// constrained intrinsic rounding mode metadata. |
53 | std::optional<StringRef> convertRoundingModeToStr(RoundingMode); |
54 | |
55 | /// Returns a valid ExceptionBehavior enumerator when given a string |
56 | /// valid as input in constrained intrinsic exception behavior metadata. |
57 | std::optional<fp::ExceptionBehavior> convertStrToExceptionBehavior(StringRef); |
58 | |
59 | /// For any ExceptionBehavior enumerator, returns a string valid as |
60 | /// input in constrained intrinsic exception behavior metadata. |
61 | std::optional<StringRef> convertExceptionBehaviorToStr(fp::ExceptionBehavior); |
62 | |
63 | /// Returns true if the exception handling behavior and rounding mode |
64 | /// match what is used in the default floating point environment. |
65 | inline bool isDefaultFPEnvironment(fp::ExceptionBehavior EB, RoundingMode RM) { |
66 | return EB == fp::ebIgnore && RM == RoundingMode::NearestTiesToEven; |
67 | } |
68 | |
69 | /// Returns constrained intrinsic id to represent the given instruction in |
70 | /// strictfp function. If the instruction is already a constrained intrinsic or |
71 | /// does not have a constrained intrinsic counterpart, the function returns |
72 | /// zero. |
73 | Intrinsic::ID getConstrainedIntrinsicID(const Instruction &Instr); |
74 | |
75 | /// Returns true if the rounding mode RM may be QRM at compile time or |
76 | /// at run time. |
77 | inline bool canRoundingModeBe(RoundingMode RM, RoundingMode QRM) { |
78 | return RM == QRM || RM == RoundingMode::Dynamic; |
79 | } |
80 | |
81 | /// Returns true if the possibility of a signaling NaN can be safely |
82 | /// ignored. |
83 | inline bool canIgnoreSNaN(fp::ExceptionBehavior EB, FastMathFlags FMF) { |
84 | return (EB == fp::ebIgnore || FMF.noNaNs()); |
85 | } |
86 | } |
87 | #endif |
88 | |