h8300.c (WORD_REG_USED): Update to avoid useless register saves in interrupt…

h8300.c (WORD_REG_USED): Update to avoid useless register saves in interrupt functions and functions...

        * h8300.c (WORD_REG_USED): Update to avoid useless register
        saves in interrupt functions and functions which never return.

From-SVN: r29724

gcc/ChangeLog

@@ -10,6 +10,9 @@ Thu Sep 30 00:13:27 1999  Dirk Zoller  <duz@rtsffm.com>
 
 Wed Sep 29 23:43:39 1999  Jeffrey A Law  (law@cygnus.com)
 
+	* h8300.c (WORD_REG_USED): Update to avoid useless register
+	saves in interrupt functions and functions which never return.
+
 	* cse.c (struct set): Delete inner_dest_loc field. 
 	(cse_insn): Remove assignments to inner_dest_loc field.
 

gcc/config/h8300/h8300.c

@@ -124,11 +124,21 @@ byte_reg (x, b)
 /* REGNO must be saved/restored across calls if this macro is true.  */
 
 #define WORD_REG_USED(regno)					\
-  (regno < 7 &&							\
-   (interrupt_handler						\
-    || pragma_saveall						\
-    || (regno == FRAME_POINTER_REGNUM && regs_ever_live[regno])	\
-    || (regs_ever_live[regno] && !call_used_regs[regno])))
+  (regno < 7							\
+   /* No need to save registers if this function will not return.*/\
+   && ! TREE_THIS_VOLATILE (current_function_decl)		\
+   && (pragma_saveall						\
+       /* Save any call saved register that was used.  */	\
+       || (regs_ever_live[regno] && !call_used_regs[regno])	\
+       /* Save the frame pointer if it was used.  */		\
+       || (regno == FRAME_POINTER_REGNUM && regs_ever_live[regno])\
+       /* Save any register used in an interrupt handler.  */	\
+       || (interrupt_handler && regs_ever_live[regno])		\
+       /* Save call clobbered registers in non-leaf interrupt	\
+	  handlers.  */						\
+       || (interrupt_handler					\
+	   && call_used_regs[regno]				\
+	   && !current_function_is_leaf)))
 
 /* Output assembly language to FILE for the operation OP with operand size
    SIZE to adjust the stack pointer.  */