Skip to content

compiler: make TARGET_ATTRIBUTE and LIKELY/UNLIKELY capability checks consistent under clang-cl #4729

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
matevz-kovacic wants to merge 2 commits into
base: dev
Choose a base branch
from
+30 −3
Open

compiler: make TARGET_ATTRIBUTE and LIKELY/UNLIKELY capability checks consistent under clang-cl #4729

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
b81b64a
compiler: apply TARGET_ATTRIBUTE under clang-cl, not only under __GNUC__
matevz-kovacic Aug 6, 2026
4afc10e
compiler: honour LIKELY/UNLIKELY under clang-cl
matevz-kovacic Aug 6, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
33 changes: 30 additions & 3 deletions lib/common/compiler.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -118,8 +118,26 @@
#endif


/* target attribute */
#if defined(__GNUC__) || defined(__IAR_SYSTEMS_ICC__)
/* target attribute
*
* This condition must stay in sync with the one DYNAMIC_BMI2 uses in
* portability_macros.h. clang in MSVC-compatible mode (clang-cl) supports
* __attribute__((__target__)) but does not define __GNUC__, so testing
* __GNUC__ alone silently expands this to nothing while DYNAMIC_BMI2
* remains enabled -- the runtime dispatch then calls _bmi2 entry points
* that were compiled with no BMI2 at all.
*/
#if defined(__has_attribute)
# if __has_attribute(__target__)
# define ZSTD_HAS_TARGET_ATTRIBUTE 1
# endif
#endif
#if !defined(ZSTD_HAS_TARGET_ATTRIBUTE) && \
(defined(__GNUC__) || defined(__IAR_SYSTEMS_ICC__))
# define ZSTD_HAS_TARGET_ATTRIBUTE 1
#endif

#if defined(ZSTD_HAS_TARGET_ATTRIBUTE)
# define TARGET_ATTRIBUTE(target) __attribute__((__target__(target)))
#else
# define TARGET_ATTRIBUTE(target)
Expand Down Expand Up @@ -183,7 +201,16 @@
* If you can remove a LIKELY/UNLIKELY annotation without speed changes in gcc
* and clang, please do.
*/
#if defined(__GNUC__)
#if defined(__has_builtin)
# if __has_builtin(__builtin_expect)
# define ZSTD_HAS_BUILTIN_EXPECT 1
# endif
#endif
#if !defined(ZSTD_HAS_BUILTIN_EXPECT) && defined(__GNUC__)
# define ZSTD_HAS_BUILTIN_EXPECT 1
#endif

#if defined(ZSTD_HAS_BUILTIN_EXPECT)
#define LIKELY(x) (__builtin_expect((x), 1))
#define UNLIKELY(x) (__builtin_expect((x), 0))
#else
Expand Down