[PPC] Fix PR88343.

Message ID 40EA3BFC-C4F7-4CA0-9C65-19C47AA3C74D@sandoe.co.uk
State New
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Series
  • [PPC] Fix PR88343.
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Commit Message

Iain Sandoe Dec. 5, 2018, 5:10 p.m.
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  <segher@kernel.crashing.org>
	   Iain Sandoe  <iain@sandoe.co.uk>

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.

Comments

Segher Boessenkool Dec. 5, 2018, 6:11 p.m. | #1
On Wed, Dec 05, 2018 at 05:10:07PM +0000, 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  <segher@kernel.crashing.org>

> 	   Iain Sandoe  <iain@sandoe.co.uk>

> 

> 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

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;
 }