On Wed, Jun 02, 2021 at 04:24:43PM +0800, Po-Hsu Lin wrote: > Compilation on Ubuntu Xenial 4.4.0-210-generic i386 with gcc version 5.4.0 > 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.12) will fail with: > lib/linux/compiler.h:37:34: error: implicit declaration of function > ‘__builtin_add_overflow_p’ [-Werror=implicit-function-declaration] > > From the GCC document[1] it looks like this built-in function was only > introduced since 7.1.0 > > This can be fixed by simply changing the version check from 5.1.0 to 7.1.0 > > [1] https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/Integer-Overflow-Builtins.html > > Signed-off-by: Po-Hsu Lin <po-hsu.lin@xxxxxxxxxxxxx> > --- > lib/linux/compiler.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/linux/compiler.h b/lib/linux/compiler.h > index 745792a..5d9552a 100644 > --- a/lib/linux/compiler.h > +++ b/lib/linux/compiler.h > @@ -30,7 +30,7 @@ > __builtin_mul_overflow(a, b, &__d); \ > }) > #endif > -#elif GCC_VERSION >= 50100 > +#elif GCC_VERSION >= 70100 > #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1 > #define check_add_overflow(a, b) __builtin_add_overflow_p(a, b, (typeof((a) + (b)))0) > #define check_sub_overflow(a, b) __builtin_add_overflow_p(a, b, (typeof((a) - (b)))0) > -- > 2.25.1 > Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
