[pushed] Darwin, PPC : Fix R13 for PPC64.

[Iain Sandoe <iains.gcc@gmail.com>]

Hi,

We have a somewhat unusual situation in that for PPC64, R13 is
both reserved for future use by the ABI document and callee-saved.
In fact, it is already  used internally by the pthreads
implementation to contain pthread_self.

So add R13 to the fixed regs, but also keep it in the callee-
saved set.

tested on powerpc-darwin9, pushed to master,
thanks
Iain

gcc/ChangeLog:

	* config/rs6000/darwin.h (FIXED_R13): Add for PPC64.
	(FIRST_SAVED_GP_REGNO): Save from R13 even when it is one
	of the fixed regs.
---
 gcc/config/rs6000/darwin.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/gcc/config/rs6000/darwin.h b/gcc/config/rs6000/darwin.h
index 6abf8e84f54..120b01f9a2b 100644
--- a/gcc/config/rs6000/darwin.h
+++ b/gcc/config/rs6000/darwin.h
@@ -203,7 +203,7 @@
 
 /* Make both r2 and r13 available for allocation.  */
 #define FIXED_R2 0
-#define FIXED_R13 0
+#define FIXED_R13 TARGET_64BIT
 
 /* Base register for access to local variables of the function.  */
 
@@ -213,6 +213,9 @@
 #undef  RS6000_PIC_OFFSET_TABLE_REGNUM
 #define RS6000_PIC_OFFSET_TABLE_REGNUM 31
 
+#undef FIRST_SAVED_GP_REGNO
+#define FIRST_SAVED_GP_REGNO 13
+
 /* Darwin's stack must remain 16-byte aligned for both 32 and 64 bit
    ABIs.  */
 
-- 
2.24.3 (Apple Git-128)