On 2017-06-19 13:25, David Rientjes wrote:
On Mon, 19 Jun 2017, Prasad Sodagudi wrote:
Commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused
static inline functions") re-defining the 'inline' macro but
__attribute__((always_inline)) is missing. Some compilers may
not honor inline hint if always_iniline attribute not there.
So add always_inline attribute to inline as done by
compiler-gcc.h file.
IIUC, __attribute__((always_inline)) was only needed for gcc versions <
4
and that the inlining decision making is improved in >= 4. To make a
change like this, I would think that we would need to show that clang
is
making suboptimal decisions. I don't think there's a downside to
making
CONFIG_OPTIMIZE_INLINING specific only to gcc.
If it is shown that __attribute__((always_inline)) is needed for clang
as
well, this should be done as part of compiler-gcc.h to avoid duplicated
code.
Hi David,
Here is the discussion about this change -
https://lkml.org/lkml/2017/6/15/396
Please check mark and will's comments.
-Thanks, Prasad
Signed-off-by: Prasad Sodagudi <psoda...@codeaurora.org>
---
include/linux/compiler-clang.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/compiler-clang.h
b/include/linux/compiler-clang.h
index d614c5e..deb65b3 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -22,4 +22,9 @@
* directives. Suppress the warning in clang as well.
*/
#undef inline
+#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
+ !defined(CONFIG_OPTIMIZE_INLINING)
+#define inline inline __attribute__((always_inline))
__attribute__((unused)) notrace
+#else
#define inline inline __attribute__((unused)) notrace
+#endif
--
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