Re: [obv][commit] Replace one/two use variables with their values

[Yao Qi <yao at codesourcery dot com>]

On 09/17/2012 05:01 PM, Siddhesh Poyarekar wrote:
> Hi,
>
> I have committed another obvious patch that replaces variables that are
> used just once or twice, directly with their values.

What is your motivation of this change?  Does this patch suggest that 
we'd better use marcro rather than local variables?  I understand most 
of it, but ...

> @@ -330,12 +327,11 @@
>         if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (TYPE_TARGET_TYPE
> (type)) > 0) {
>   	  elttype = check_typedef (TYPE_TARGET_TYPE (type));
> -	  eltlen = TYPE_LENGTH (elttype);
> -	  len = TYPE_LENGTH (type) / eltlen;
> +	  len = TYPE_LENGTH (type) / TYPE_LENGTH (elttype);
>   	  if (options->prettyprint_arrays)
>   	    print_spaces_filtered (2 + 2 * recurse, stream);
>   	  /* For an array of chars, print with string syntax.  */
> -	  if (eltlen == 1 &&
> +	  if (TYPE_LENGTH (elttype) == 1 &&
>   	      ((TYPE_CODE (elttype) == TYPE_CODE_INT)
>   	       || ((current_language->la_language == language_m2)
>   		   && (TYPE_CODE (elttype) == TYPE_CODE_CHAR)))

... this part.  We define a local variable 'eltlen', and use it twice. 
Isn't a common programming practise?  I don't object to this patch, but 
want to know why do we do this change?

> ===================================================================
> RCS file: /cvs/src/src/gdb/m68k-tdep.c,v
> retrieving revision 1.159
> retrieving revision 1.160
> diff -u -r1.159 -r1.160
> --- src/gdb/m68k-tdep.c	2012/07/24 16:37:24	1.159
> +++ src/gdb/m68k-tdep.c	2012/09/17 08:52:18	1.160
> @@ -315,7 +315,6 @@
>   m68k_svr4_extract_return_value (struct type *type, struct regcache
> *regcache, gdb_byte *valbuf)
>   {
> -  int len = TYPE_LENGTH (type);
>     gdb_byte buf[M68K_MAX_REGISTER_SIZE];
>     struct gdbarch *gdbarch = get_regcache_arch (regcache);
>     struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> @@ -326,7 +325,7 @@
>         regcache_raw_read (regcache, M68K_FP0_REGNUM, buf);
>         convert_typed_floating (buf, fpreg_type, valbuf, type);
>       }
> -  else if (TYPE_CODE (type) == TYPE_CODE_PTR && len == 4)
> +  else if (TYPE_CODE (type) == TYPE_CODE_PTR && TYPE_LENGTH (type) ==
> 4) regcache_raw_read (regcache, M68K_A0_REGNUM, valbuf);

b.t.w, looks your mailer wrap your patch incorrectly.

--
Yao