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| Started by | Rasmus Villemoes <linux@rasmusvillemoes.dk> |
|---|---|
| First post | 2015-11-23 22:40 +0100 |
| Last post | 2015-11-23 23:20 +0100 |
| Articles | 2 — 2 participants |
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[PATCH 05/14] lib/vsprintf.c: help gcc make number() smaller Rasmus Villemoes <linux@rasmusvillemoes.dk> - 2015-11-23 22:40 +0100
Re: [PATCH 05/14] lib/vsprintf.c: help gcc make number() smaller Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-11-23 23:20 +0100
| From | Rasmus Villemoes <linux@rasmusvillemoes.dk> |
|---|---|
| Date | 2015-11-23 22:40 +0100 |
| Subject | [PATCH 05/14] lib/vsprintf.c: help gcc make number() smaller |
| Message-ID | <qy706-7p3-15@gated-at.bofh.it> |
One consequence of the reorganization of struct printf_spec to make
field_width 24 bits was that number() gained about 180 bytes. Since
spec is never passed to other functions, we can help gcc make number()
lose most of that extra weight by using local variables for the field
width and precision.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
lib/vsprintf.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 01c3aa638582..d7e27c54fa00 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -399,6 +399,8 @@ char *number(char *buf, char *end, unsigned long long num,
int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
int i;
bool is_zero = num == 0LL;
+ int field_width = spec.field_width;
+ int precision = spec.precision;
/* locase = 0 or 0x20. ORing digits or letters with 'locase'
* produces same digits or (maybe lowercased) letters */
@@ -410,20 +412,20 @@ char *number(char *buf, char *end, unsigned long long num,
if ((signed long long)num < 0) {
sign = '-';
num = -(signed long long)num;
- spec.field_width--;
+ field_width--;
} else if (spec.flags & PLUS) {
sign = '+';
- spec.field_width--;
+ field_width--;
} else if (spec.flags & SPACE) {
sign = ' ';
- spec.field_width--;
+ field_width--;
}
}
if (need_pfx) {
if (spec.base == 16)
- spec.field_width -= 2;
+ field_width -= 2;
else if (!is_zero)
- spec.field_width--;
+ field_width--;
}
/* generate full string in tmp[], in reverse order */
@@ -445,12 +447,12 @@ char *number(char *buf, char *end, unsigned long long num,
}
/* printing 100 using %2d gives "100", not "00" */
- if (i > spec.precision)
- spec.precision = i;
+ if (i > precision)
+ precision = i;
/* leading space padding */
- spec.field_width -= spec.precision;
+ field_width -= precision;
if (!(spec.flags & (ZEROPAD | LEFT))) {
- while (--spec.field_width >= 0) {
+ while (--field_width >= 0) {
if (buf < end)
*buf = ' ';
++buf;
@@ -479,14 +481,14 @@ char *number(char *buf, char *end, unsigned long long num,
if (!(spec.flags & LEFT)) {
char c = ' ' + (spec.flags & ZEROPAD);
BUILD_BUG_ON(' ' + ZEROPAD != '0');
- while (--spec.field_width >= 0) {
+ while (--field_width >= 0) {
if (buf < end)
*buf = c;
++buf;
}
}
/* hmm even more zero padding? */
- while (i <= --spec.precision) {
+ while (i <= --precision) {
if (buf < end)
*buf = '0';
++buf;
@@ -498,7 +500,7 @@ char *number(char *buf, char *end, unsigned long long num,
++buf;
}
/* trailing space padding */
- while (--spec.field_width >= 0) {
+ while (--field_width >= 0) {
if (buf < end)
*buf = ' ';
++buf;
--
2.6.1
--
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| From | Andy Shevchenko <andy.shevchenko@gmail.com> |
|---|---|
| Date | 2015-11-23 23:20 +0100 |
| Message-ID | <qy7CQ-7Sa-31@gated-at.bofh.it> |
| In reply to | #1275869 |
On Mon, Nov 23, 2015 at 11:29 PM, Rasmus Villemoes
<linux@rasmusvillemoes.dk> wrote:
> One consequence of the reorganization of struct printf_spec to make
> field_width 24 bits was that number() gained about 180 bytes. Since
> spec is never passed to other functions, we can help gcc make number()
> lose most of that extra weight by using local variables for the field
> width and precision.
>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
One minor nitpick below
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> ---
> lib/vsprintf.c | 26 ++++++++++++++------------
> 1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 01c3aa638582..d7e27c54fa00 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -399,6 +399,8 @@ char *number(char *buf, char *end, unsigned long long num,
> int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
> int i;
> bool is_zero = num == 0LL;
> + int field_width = spec.field_width;
> + int precision = spec.precision;
I would put these before int i; But your choice.
>
> /* locase = 0 or 0x20. ORing digits or letters with 'locase'
> * produces same digits or (maybe lowercased) letters */
> @@ -410,20 +412,20 @@ char *number(char *buf, char *end, unsigned long long num,
> if ((signed long long)num < 0) {
> sign = '-';
> num = -(signed long long)num;
> - spec.field_width--;
> + field_width--;
> } else if (spec.flags & PLUS) {
> sign = '+';
> - spec.field_width--;
> + field_width--;
> } else if (spec.flags & SPACE) {
> sign = ' ';
> - spec.field_width--;
> + field_width--;
> }
> }
> if (need_pfx) {
> if (spec.base == 16)
> - spec.field_width -= 2;
> + field_width -= 2;
> else if (!is_zero)
> - spec.field_width--;
> + field_width--;
> }
>
> /* generate full string in tmp[], in reverse order */
> @@ -445,12 +447,12 @@ char *number(char *buf, char *end, unsigned long long num,
> }
>
> /* printing 100 using %2d gives "100", not "00" */
> - if (i > spec.precision)
> - spec.precision = i;
> + if (i > precision)
> + precision = i;
> /* leading space padding */
> - spec.field_width -= spec.precision;
> + field_width -= precision;
> if (!(spec.flags & (ZEROPAD | LEFT))) {
> - while (--spec.field_width >= 0) {
> + while (--field_width >= 0) {
> if (buf < end)
> *buf = ' ';
> ++buf;
> @@ -479,14 +481,14 @@ char *number(char *buf, char *end, unsigned long long num,
> if (!(spec.flags & LEFT)) {
> char c = ' ' + (spec.flags & ZEROPAD);
> BUILD_BUG_ON(' ' + ZEROPAD != '0');
> - while (--spec.field_width >= 0) {
> + while (--field_width >= 0) {
> if (buf < end)
> *buf = c;
> ++buf;
> }
> }
> /* hmm even more zero padding? */
> - while (i <= --spec.precision) {
> + while (i <= --precision) {
> if (buf < end)
> *buf = '0';
> ++buf;
> @@ -498,7 +500,7 @@ char *number(char *buf, char *end, unsigned long long num,
> ++buf;
> }
> /* trailing space padding */
> - while (--spec.field_width >= 0) {
> + while (--field_width >= 0) {
> if (buf < end)
> *buf = ' ';
> ++buf;
> --
> 2.6.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
With Best Regards,
Andy Shevchenko
--
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