| commit | 1354ec840899e87259286cc844d4c161ea86fae7 | [log] [tgz] |
|---|---|---|
| author | Rikard Falkeborn <rikard.falkeborn@gmail.com> | Sat May 22 17:42:02 2021 -0700 |
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | Thu Jun 03 09:00:45 2021 +0200 |
| tree | 513087186e54c88ed5e6bee6d23dd23a416a82a6 | |
| parent | b0f5d4891ea3a80ad619312355494dc25073e219 [diff] |
linux/bits.h: fix compilation error with GENMASK [ Upstream commit f747e6667ebb2ffb8133486c9cd19800d72b0d98 ] GENMASK() has an input check which uses __builtin_choose_expr() to enable a compile time sanity check of its inputs if they are known at compile time. However, it turns out that __builtin_constant_p() does not always return a compile time constant [0]. It was thought this problem was fixed with gcc 4.9 [1], but apparently this is not the case [2]. Switch to use __is_constexpr() instead which always returns a compile time constant, regardless of its inputs. Link: https://lore.kernel.org/lkml/42b4342b-aefc-a16a-0d43-9f9c0d63ba7a@rasmusvillemoes.dk [0] Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19449 [1] Link: https://lore.kernel.org/lkml/1ac7bbc2-45d9-26ed-0b33-bf382b8d858b@I-love.SAKURA.ne.jp [2] Link: https://lkml.kernel.org/r/20210511203716.117010-1-rikard.falkeborn@gmail.com Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>