3.2.101-rc1 review patch. If anyone has any objections, please let me know.
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From: Arnd Bergmann arnd@arndb.de
commit e74fc973b6e531fef1fce8b101ffff05ecfb774c upstream.
gcc-4.7 and higher add a lot of false positive warnings about potential uses of uninitialized warnings, but only when optimizing for size (-Os). This is the default when building allyesconfig, which turns on CONFIG_CC_OPTIMIZE_FOR_SIZE.
In order to avoid getting a lot of patches that initialize such variables and accidentally hide real errors along the way, let's just turn off this warning on the respective gcc versions when building with size optimizations. The -Wmaybe-uninitialized option was introduced in the same gcc version (4.7) that is now causing the false positives, so there is no effect on older compilers.
A side effect is that when building with CONFIG_CC_OPTIMIZE_FOR_SIZE, we might now see /fewer/ warnings about possibly uninitialized warnings than with -O2, but that is still much better than seeing warnings known to be bogus.
Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Ben Hutchings ben@decadent.org.uk --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/Makefile +++ b/Makefile @@ -559,7 +559,7 @@ endif # $(dot-config) all: vmlinux
ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE -KBUILD_CFLAGS += -Os +KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) else KBUILD_CFLAGS += -O2 endif