From: Alexey Dobriyan Date: Mon, 10 Jul 2017 22:51:41 +0000 (-0700) Subject: lib/kstrtox.c: use "unsigned int" more X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=be5f3c7774a158c5bd08de22d54b0612f954dfa8;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git lib/kstrtox.c: use "unsigned int" more gcc does generates stupid code sign extending data back and forth. Help by using "unsigned int". add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-61 (-61) function old new delta _parse_integer 128 123 -5 It _still_ does generate useless MOVSX but I don't know how to delete it: 0000000000000070 <_parse_integer>: ... a0: 89 c2 mov edx,eax a2: 83 e8 30 sub eax,0x30 a5: 83 f8 09 cmp eax,0x9 a8: 76 11 jbe bb <_parse_integer+0x4b> aa: 83 ca 20 or edx,0x20 ad: 0f be c2 ===> movsx eax,dl <=== useless b0: 8d 50 9f lea edx,[rax-0x61] b3: 83 fa 05 cmp edx,0x5 Patch also helps on embedded archs which generally only like "int". On arm "and 0xff" is generated which is waste because all values used in comparisons are positive. Link: http://lkml.kernel.org/r/20170514194720.GB32563@avx2 Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/lib/kstrtox.c b/lib/kstrtox.c index 90013f4841c7..720144075c1e 100644 --- a/lib/kstrtox.c +++ b/lib/kstrtox.c @@ -52,12 +52,14 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long res = 0; rv = 0; while (1) { + unsigned int c = *s; + unsigned int lc = c | 0x20; /* don't tolower() this line */ unsigned int val; - if ('0' <= *s && *s <= '9') - val = *s - '0'; - else if ('a' <= _tolower(*s) && _tolower(*s) <= 'f') - val = _tolower(*s) - 'a' + 10; + if ('0' <= c && c <= '9') + val = c - '0'; + else if ('a' <= lc && lc <= 'f') + val = lc - 'a' + 10; else break;