Re: [PATCH, PPC] Fix PR88343.

[Segher Boessenkool]

On Wed, Dec 05, 2018 at 05:10:07PM +, Iain Sandoe wrote:
> Hi,
> 
> The PR is about unnecessary saves of the pic base register, it shows on m32 
> Linux and m32/m64 Darwin.
> 
> The fix is to check that we are in a pic mode and that the picbase has 
> actually been used.
> As a bonus, some #ifdef’d TARGET_MACHO code is no longer required.
> 
> Tested on power7, bootstrapped on Darwin (testing continues).
> 
> OK for trunk?

Okay for trunk if testing completes successfully :-)  Thanks!

> Branches?

Sure.  Please let is soak on trunk for a week first; and don't do 7
until 7.4 has been made?


> 2018-xx-xx  Segher Boessenkool  
>  Iain Sandoe  
> 
> gcc/
>   * config/rs6000/rs6000.c (save_reg_p): Do not save the picbase reg
>   unless it has been used.  (first_reg_to_save): Remove dead code.

Your changelogs still wrap (the second "(" should start a new line).


Segher

[PATCH, PPC] Fix PR88343.

[Iain Sandoe]

Hi,

The PR is about unnecessary saves of the pic base register, it shows on m32 
Linux and m32/m64 Darwin.

The fix is to check that we are in a pic mode and that the picbase has actually 
been used.
As a bonus, some #ifdef’d TARGET_MACHO code is no longer required.

Tested on power7, bootstrapped on Darwin (testing continues).

OK for trunk?

Branches?

Iain

2018-xx-xx  Segher Boessenkool  
   Iain Sandoe  

gcc/
* config/rs6000/rs6000.c (save_reg_p): Do not save the picbase reg
unless it has been used.  (first_reg_to_save): Remove dead code.


diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index dfd5303..380cf9d 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -23961,7 +23961,7 @@ save_reg_p (int reg)
return true;
 
   if ((DEFAULT_ABI == ABI_V4 || DEFAULT_ABI == ABI_DARWIN)
- && flag_pic)
+ && flag_pic && crtl->uses_pic_offset_table)
return true;
 }
 
@@ -23981,13 +23981,6 @@ first_reg_to_save (void)
 if (save_reg_p (first_reg))
   break;
 
-#if TARGET_MACHO
-  if (flag_pic
-  && crtl->uses_pic_offset_table
-  && first_reg > RS6000_PIC_OFFSET_TABLE_REGNUM)
-return RS6000_PIC_OFFSET_TABLE_REGNUM;
-#endif
-
   return first_reg;
 }