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[PATCH 3/4] lib/vsprintf.c: Remove SPECIAL handling in pointer()

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  [PATCH 3/4] lib/vsprintf.c: Remove SPECIAL handling in pointer() Rasmus Villemoes <linux@rasmusvillemoes.dk> - 2015-09-25 19:50 +0200
    Re: [PATCH 3/4] lib/vsprintf.c: Remove SPECIAL handling in pointer() Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2015-09-28 11:00 +0200

#1232970 — [PATCH 3/4] lib/vsprintf.c: Remove SPECIAL handling in pointer()

As a quick

   git grep -E '%[ +0#-]*#[ +0#-]*(\*|[0-9]+)?(\.(\*|[0-9]+)?)?p'

shows, nobody uses the # flag with %p. Moreover, I think users are
unlikely to show up since gcc will complain with

  warning: `#' flag used with ‘%p’ gnu_printf format [-Wformat]

Since default_width is effectively always 2*sizeof(void*), we can
simplify the prologue of pointer() and save a few instructions.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 lib/vsprintf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 03fa10b4be96..98b0d7be3fb7 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1457,7 +1457,7 @@ static noinline_for_stack
 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 	      struct printf_spec spec)
 {
-	int default_width = 2 * sizeof(void *) + (spec.flags & SPECIAL ? 2 : 0);
+	const int default_width = 2 * sizeof(void *);
 
 	if (!ptr && *fmt != 'K') {
 		/*
-- 
2.1.3

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#1233952

On Fri, 2015-09-25 at 19:41 +0200, Rasmus Villemoes wrote:
> As a quick
> 
>    git grep -E '%[ +0#-]*#[ +0#-]*(\*|[0-9]+)?(\.(\*|[0-9]+)?)?p'
> 
> shows, nobody uses the # flag with %p. Moreover, I think users are
> unlikely to show up since gcc will complain with
> 
>   warning: `#' flag used with ‘%p’ gnu_printf format [-Wformat]

I would refer to POSIX here

"# Specifies that the value is to be converted to an alternative form.
...
For other conversion specifiers, the behavior is undefined."

> 
> Since default_width is effectively always 2*sizeof(void*), we can
> simplify the prologue of pointer() and save a few instructions.
> 
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> ---
>  lib/vsprintf.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 03fa10b4be96..98b0d7be3fb7 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -1457,7 +1457,7 @@ static noinline_for_stack
>  char *pointer(const char *fmt, char *buf, char *end, void *ptr,
>  	      struct printf_spec spec)
>  {
> -	int default_width = 2 * sizeof(void *) + (spec.flags & 
> SPECIAL ? 2 : 0);
> +	const int default_width = 2 * sizeof(void *);
>  
>  	if (!ptr && *fmt != 'K') {
>  		/*

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
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