ref: e7d4e82bc065747d94829d93cc9d8a9d1eab7951
parent: 556c2d446b396cff11987ac1b74ed7bbf0297d78
author: Timothy B. Terriberry <tterribe@xiph.org>
date: Thu Mar 14 04:00:53 EDT 2024
Fix _mm_loadu_si32 detection for vendored Clang. Apple uses different __clang_major__ version numbers than upstream, so our test did not work. This caused compilation failures with, e.g., XCode 10.1, which reports __clang_major__ as 10 despite being forked from upstream's 7.0 branch. Fixes #2369 Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>
--- a/celt/x86/x86cpu.h
+++ b/celt/x86/x86cpu.h
@@ -68,8 +68,22 @@
Use this to work around those restrictions (which should hopefully all get
optimized to a single MOVD instruction).
GCC implemented _mm_loadu_si32() since GCC 11; HOWEVER, there is a bug!
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99754 */
-# if !defined(_MSC_VER) && !OPUS_GNUC_PREREQ(11,3) && !(defined(__clang__) && (__clang_major__ >= 8))
+ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99754
+ LLVM implemented _mm_loadu_si32() since Clang 8.0, however the
+ __clang_major__ version number macro is unreliable, as vendors
+ (specifically, Apple) will use different numbering schemes than upstream.
+ Clang's advice is "use feature detection", but they do not provide feature
+ detection support for specific SIMD functions.
+ We follow the approach from the SIMDe project and instead detect unrelated
+ features that should be available in the version we want (see
+ <https://github.com/simd-everywhere/simde/blob/master/simde/simde-detect-clang.h>).*/
+# if defined(__clang__)
+# if __has_warning("-Wextra-semi-stmt") || \+ __has_builtin(__builtin_rotateleft32)
+# define OPUS_CLANG_8 (1)
+# endif
+# endif
+# if !defined(_MSC_VER) && !OPUS_GNUC_PREREQ(11,3) && !defined(OPUS_CLANG_8)
# include <string.h>
# include <emmintrin.h>
--
⑨