diff mbox series

[to-be-updated] linux-compiler-clangh-define-have_builtin_bswap.patch removed from -mm tree

Message ID 20210303012338.CEzHUdBK8%akpm@linux-foundation.org
State New
Headers show
Series [to-be-updated] linux-compiler-clangh-define-have_builtin_bswap.patch removed from -mm tree | expand

Commit Message

Andrew Morton March 3, 2021, 1:23 a.m. UTC 
The patch titled
     Subject: linux/compiler-clang.h: define HAVE_BUILTIN_BSWAP*
has been removed from the -mm tree.  Its filename was
     linux-compiler-clangh-define-have_builtin_bswap.patch

This patch was dropped because an updated version will be merged

------------------------------------------------------
From: Arnd Bergmann <arnd@arndb.de>
Subject: linux/compiler-clang.h: define HAVE_BUILTIN_BSWAP*

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.

Link: https://lkml.kernel.org/r/20210225164513.3667778-1-arnd@kernel.org
Fixes: 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/compiler-clang.h |   10 ++++++++++
 1 file changed, 10 insertions(+)
diff mbox series

Patch

--- a/include/linux/compiler-clang.h~linux-compiler-clangh-define-have_builtin_bswap
+++ a/include/linux/compiler-clang.h
@@ -31,6 +31,16 @@ 
 #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 \