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lib/kstrtox.c: smaller _parse_integer() 

Set "overflow" bit upon encountering it instead of postponing to the end
of the conversion. Somehow gcc unwedges itself and generates better code:

	$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux
	_parse_integer                      177     139     -38

Inspired by patch from Zhaoxiu Zeng.

Link: http://lkml.kernel.org/r/20160826221920.GA1909@p183.telecom.by
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan 2016-10-11 13:51:32 -07:00 committed by Linus Torvalds
parent 1204c77f9b
commit 8cfd56d479
1 changed files with 1 additions and 5 deletions
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6
lib/kstrtox.c
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@ -48,11 +48,9 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
{
unsigned long long res;
unsigned int rv;
int overflow;
res = 0;
rv = 0;
overflow = 0;
while (*s) {
unsigned int val;
@ -71,15 +69,13 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long
*/
if (unlikely(res & (~0ull << 60))) {
if (res > div_u64(ULLONG_MAX - val, base))
overflow = 1;
rv |= KSTRTOX_OVERFLOW;
}
res = res * base + val;
rv++;
s++;
}
*p = res;
if (overflow)
rv |= KSTRTOX_OVERFLOW;
return rv;
}