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

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

From-SVN: r29724

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 801b23585da7cbc54a3297893fcfef5c8744a58e..44b00e5c061ba954434f1ace532bc5c17929c6c8 100644 (file)
--- a/gcc/ChangeLog
+++ b/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.
 

diff --git a/gcc/config/h8300/h8300.c b/gcc/config/h8300/h8300.c
index 8710e23d992a0c42006bce944b568dab8edf98ac..ede0839b2973a3804e343375f0a28159e0dc3c52 100644 (file)
--- a/gcc/config/h8300/h8300.c
+++ b/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.  */