[PATCH, PPC] Fix PR88343.

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

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.


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;
 }