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lib: uninline simple_strtoull()

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Gcc inlines simple_strtoull() too agressively.

Given that all 4 signatures match, everything very efficiently calls or
tailcalls into simple_strtoull():

	ffffffff81da0240 <simple_strtoll>:
	ffffffff81da0240:       80 3f 2d                cmp    BYTE PTR [rdi],0x2d
	ffffffff81da0243:       74 05                   je     ffffffff81da024a <simple_strtoll+0xa>
	ffffffff81da0245:       e9 76 ff ff ff          jmp    simple_strtoull
	ffffffff81da024a:       48 83 c7 01             add    rdi,0x1
	ffffffff81da024e:       e8 6d ff ff ff          call   simple_strtoull
	ffffffff81da0253:       48 f7 d8                neg    rax
	ffffffff81da0256:       c3                      ret

Space savings (on F34-ish .config)

	add/remove: 0/0 grow/shrink: 1/3 up/down: 52/-313 (-261)
	Function                                     old     new   delta
	vsscanf                                     2167    2219     +52
	simple_strtoul                                72       2     -70
	simple_strtoll                               143      23    -120
	simple_strtol                                143      20    -123

Link: https://lkml.kernel.org/r/YMO2zoOQk2eF34tn@localhost.localdomain
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 2021-06-30 18:56:04 -07:00 committed by Linus Torvalds
parent 1a58be6277
commit ad65dcef3a
1 changed files with 1 additions and 0 deletions
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1
lib/vsprintf.c
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@ -61,6 +61,7 @@
*
* This function has caveats. Please use kstrtoull instead.
*/
noinline
unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
{
unsigned long long result;