hints.h
Go to the documentation of this file.
1 //
2 // Copyright 2016 Pixar
3 //
4 // Licensed under the Apache License, Version 2.0 (the "Apache License")
5 // with the following modification; you may not use this file except in
6 // compliance with the Apache License and the following modification to it:
7 // Section 6. Trademarks. is deleted and replaced with:
8 //
9 // 6. Trademarks. This License does not grant permission to use the trade
10 // names, trademarks, service marks, or product names of the Licensor
11 // and its affiliates, except as required to comply with Section 4(c) of
12 // the License and to reproduce the content of the NOTICE file.
13 //
14 // You may obtain a copy of the Apache License at
15 //
16 // http://www.apache.org/licenses/LICENSE-2.0
17 //
18 // Unless required by applicable law or agreed to in writing, software
19 // distributed under the Apache License with the above modification is
20 // distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
21 // KIND, either express or implied. See the Apache License for the specific
22 // language governing permissions and limitations under the Apache License.
23 //
24 #ifndef PXR_BASE_ARCH_HINTS_H
25 #define PXR_BASE_ARCH_HINTS_H
26 
27 #include "pxr/base/arch/defines.h"
28 
38 
39 #if defined(ARCH_COMPILER_GCC) || defined(ARCH_COMPILER_CLANG)
40 
41 #define ARCH_LIKELY(x) (__builtin_expect((bool)(x), true))
42 #define ARCH_UNLIKELY(x) (__builtin_expect((bool)(x), false))
43 
44 #else
45 
46 #define ARCH_LIKELY(x) (x)
47 #define ARCH_UNLIKELY(x) (x)
48 
49 #endif
50 
66 
67 #if defined(ARCH_COMPILER_GCC) || \
68  defined(ARCH_COMPILER_CLANG) || \
69  defined(ARCH_COMPILER_ICC)
70 
71 // Intentionally using __builtin_unreachable on clang for consistency, since
72 // __builtin_assume does not evaluate the expression, and our only option on gcc
73 // is the __builtin_unreachable branch.
74 
75 #define ARCH_GUARANTEE_TO_COMPILER(x) \
76  if (static_cast<bool>(x)) { } else { __builtin_unreachable(); }
77 
78 #else
79 
80 #define ARCH_GUARANTEE_TO_COMPILER(x)
81 
82 #endif
83 
84 
85 #endif // PXR_BASE_ARCH_HINTS_H