From: Arnd Bergmann <a...@arndb.de>
Separating compiler-clang.h from compiler-gcc.h inadventently dropped the
definitions of the three HAVE_BUILTIN_BSWAP macros, which requires falling
back to the open-coded version and hoping that the compiler detects it.
Since all versions of clang support the __builtin_bswap interfaces,
add back the flags and have the headers pick these up automatically.
This results in a 4% improvement of compilation speed for arm defconfig.
Fixes: 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually
exclusive")
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
include/linux/compiler-clang.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index 6478bff6fcc2..bbfa9ff6a2ec 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -33,6 +33,16 @@
#define __no_sanitize_thread
#endif
+/*
+ * sparse (__CHECKER__) pretends to be gcc, but can't do constant
+ * folding in __builtin_bswap*() (yet), so don't set these for it.
+ */
+#if defined(CONFIG_ARCH_USE_BUILTIN_BSWAP) && !defined(__CHECKER__)
+#define __HAVE_BUILTIN_BSWAP32__
+#define __HAVE_BUILTIN_BSWAP64__
+#define __HAVE_BUILTIN_BSWAP16__
+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP && !__CHECKER__ */
+
#if __has_feature(undefined_behavior_sanitizer)
/* GCC does not have __SANITIZE_UNDEFINED__ */
#define __no_sanitize_undefined \
--
2.29.2
