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Diffstat (limited to 'mfbt/Likely.h')
| -rw-r--r-- | mfbt/Likely.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/mfbt/Likely.h b/mfbt/Likely.h new file mode 100644 index 000000000..4f2160929 --- /dev/null +++ b/mfbt/Likely.h @@ -0,0 +1,23 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* + * MOZ_LIKELY and MOZ_UNLIKELY macros to hint to the compiler how a + * boolean predicate should be branch-predicted. + */ + +#ifndef mozilla_Likely_h +#define mozilla_Likely_h + +#if defined(__clang__) || defined(__GNUC__) +# define MOZ_LIKELY(x) (__builtin_expect(!!(x), 1)) +# define MOZ_UNLIKELY(x) (__builtin_expect(!!(x), 0)) +#else +# define MOZ_LIKELY(x) (!!(x)) +# define MOZ_UNLIKELY(x) (!!(x)) +#endif + +#endif /* mozilla_Likely_h */ |