Re: [PATCH] Remove CALLER_SAVE_PROFITABLE since nobody use it now

[Richard Earnshaw <rearnsha at arm dot com>]

On 18/08/14 15:48, Kito Cheng wrote:
> Hi all:
> 
> This patch clean up CALLER_SAVE_PROFITABLE marco include doc since
> seem nobody use it.
> 
> Bootstrap and regression testing running on x86_64-unknown-linux-gnu :)
> 
> ChangLog
> 2014-08-18  Kito Cheng  <kito@0xlab.org>
> 
>         * doc/tm.texi.in (CALLER_SAVE_PROFITABLE): Remove.
>         * gcc/doc/tm.texi: Regenerate.
>         * gcc/regs.h (CALLER_SAVE_PROFITABLE): Remove.
> 
> 

Hmm, I'm not sure about this.  It might not be used at present, but on
AArch64, with more call-clobbered registers than call-saved registers, I
would expect this ought to be a win.  The fact that it isn't on today
may say more about the way it works than the concept that it's the wrong
thing to do in principle.

R.

> 0001-Remove-CALLER_SAVE_PROFITABLE-since-nobody-use-it-no.patch
> 
> 
> From c8aeb654e6eaaeb07a1cde9a83a6340a901a4d3c Mon Sep 17 00:00:00 2001
> From: Kito Cheng <kito@0xlab.org>
> Date: Mon, 18 Aug 2014 22:09:22 +0800
> Subject: [PATCH] Remove CALLER_SAVE_PROFITABLE since nobody use it now.
> 
> ---
>  gcc/doc/tm.texi    | 10 ----------
>  gcc/doc/tm.texi.in | 10 ----------
>  gcc/regs.h         |  8 --------
>  3 files changed, 28 deletions(-)
> 
> diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
> index 9dd8d68..4d6492b 100644
> --- a/gcc/doc/tm.texi
> +++ b/gcc/doc/tm.texi
> @@ -4528,16 +4528,6 @@ If you enable it, GCC can save registers around function calls.  This
>  makes it possible to use call-clobbered registers to hold variables that
>  must live across calls.
>  
> -@defmac CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls})
> -A C expression to determine whether it is worthwhile to consider placing
> -a pseudo-register in a call-clobbered hard register and saving and
> -restoring it around each function call.  The expression should be 1 when
> -this is worth doing, and 0 otherwise.
> -
> -If you don't define this macro, a default is used which is good on most
> -machines: @code{4 * @var{calls} < @var{refs}}.
> -@end defmac
> -
>  @defmac HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
>  A C expression specifying which mode is required for saving @var{nregs}
>  of a pseudo-register in call-clobbered hard register @var{regno}.  If
> diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
> index dd72b98..7a63353 100644
> --- a/gcc/doc/tm.texi.in
> +++ b/gcc/doc/tm.texi.in
> @@ -3683,16 +3683,6 @@ If you enable it, GCC can save registers around function calls.  This
>  makes it possible to use call-clobbered registers to hold variables that
>  must live across calls.
>  
> -@defmac CALLER_SAVE_PROFITABLE (@var{refs}, @var{calls})
> -A C expression to determine whether it is worthwhile to consider placing
> -a pseudo-register in a call-clobbered hard register and saving and
> -restoring it around each function call.  The expression should be 1 when
> -this is worth doing, and 0 otherwise.
> -
> -If you don't define this macro, a default is used which is good on most
> -machines: @code{4 * @var{calls} < @var{refs}}.
> -@end defmac
> -
>  @defmac HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
>  A C expression specifying which mode is required for saving @var{nregs}
>  of a pseudo-register in call-clobbered hard register @var{regno}.  If
> diff --git a/gcc/regs.h b/gcc/regs.h
> index be81db4..36e803d 100644
> --- a/gcc/regs.h
> +++ b/gcc/regs.h
> @@ -214,14 +214,6 @@ extern short *reg_renumber;
>  
>  extern int caller_save_needed;
>  
> -/* Predicate to decide whether to give a hard reg to a pseudo which
> -   is referenced REFS times and would need to be saved and restored
> -   around a call CALLS times.  */
> -
> -#ifndef CALLER_SAVE_PROFITABLE
> -#define CALLER_SAVE_PROFITABLE(REFS, CALLS)  (4 * (CALLS) < (REFS))
> -#endif
> -
>  /* Select a register mode required for caller save of hard regno REGNO.  */
>  #ifndef HARD_REGNO_CALLER_SAVE_MODE
>  #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
>