llvm/IR/FPEnv.h

0001 //===- FPEnv.h ---- FP Environment ------------------------------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 //
0009 /// @file
0010 /// This file contains the declarations of entities that describe floating
0011 /// point environment and related functions.
0012 //
0013 //===----------------------------------------------------------------------===//
0014
0015 #ifndef LLVM_IR_FPENV_H
0016 #define LLVM_IR_FPENV_H
0017
0018 #include "llvm/ADT/FloatingPointMode.h"
0019 #include "llvm/IR/FMF.h"
0020 #include <optional>
0021
0022 namespace llvm {
0023 class StringRef;
0024
0025 namespace Intrinsic {
0026 typedef unsigned ID;
0027 }
0028
0029 class Instruction;
0030
0031 namespace fp {
0032
0033 /// Exception behavior used for floating point operations.
0034 ///
0035 /// Each of these values correspond to some metadata argument value of a
0036 /// constrained floating point intrinsic. See the LLVM Language Reference Manual
0037 /// for details.
0038 enum ExceptionBehavior : uint8_t {
0039   ebIgnore,  ///< This corresponds to "fpexcept.ignore".
0040   ebMayTrap, ///< This corresponds to "fpexcept.maytrap".
0041   ebStrict   ///< This corresponds to "fpexcept.strict".
0042 };
0043
0044 }
0045
0046 /// Returns a valid RoundingMode enumerator when given a string
0047 /// that is valid as input in constrained intrinsic rounding mode
0048 /// metadata.
0049 std::optional<RoundingMode> convertStrToRoundingMode(StringRef);
0050
0051 /// For any RoundingMode enumerator, returns a string valid as input in
0052 /// constrained intrinsic rounding mode metadata.
0053 std::optional<StringRef> convertRoundingModeToStr(RoundingMode);
0054
0055 /// Returns a valid ExceptionBehavior enumerator when given a string
0056 /// valid as input in constrained intrinsic exception behavior metadata.
0057 std::optional<fp::ExceptionBehavior> convertStrToExceptionBehavior(StringRef);
0058
0059 /// For any ExceptionBehavior enumerator, returns a string valid as
0060 /// input in constrained intrinsic exception behavior metadata.
0061 std::optional<StringRef> convertExceptionBehaviorToStr(fp::ExceptionBehavior);
0062
0063 /// Returns true if the exception handling behavior and rounding mode
0064 /// match what is used in the default floating point environment.
0065 inline bool isDefaultFPEnvironment(fp::ExceptionBehavior EB, RoundingMode RM) {
0066   return EB == fp::ebIgnore && RM == RoundingMode::NearestTiesToEven;
0067 }
0068
0069 /// Returns constrained intrinsic id to represent the given instruction in
0070 /// strictfp function. If the instruction is already a constrained intrinsic or
0071 /// does not have a constrained intrinsic counterpart, the function returns
0072 /// zero.
0073 Intrinsic::ID getConstrainedIntrinsicID(const Instruction &Instr);
0074
0075 /// Returns true if the rounding mode RM may be QRM at compile time or
0076 /// at run time.
0077 inline bool canRoundingModeBe(RoundingMode RM, RoundingMode QRM) {
0078   return RM == QRM || RM == RoundingMode::Dynamic;
0079 }
0080
0081 /// Returns true if the possibility of a signaling NaN can be safely
0082 /// ignored.
0083 inline bool canIgnoreSNaN(fp::ExceptionBehavior EB, FastMathFlags FMF) {
0084   return (EB == fp::ebIgnore || FMF.noNaNs());
0085 }
0086 }
0087 #endif