We have a somewhat unusual situation in that for PPC64, R13 is
both reserved and callee-saved (it is 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.
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.
/* 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. */
#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. */