h8300-protos.h: Declare h8300_hard_regno_rename_ok

	* config/h8300/h8300-protos.h: Declare h8300_hard_regno_rename_ok
	* config/h8300/h8300.h (HARD_REGNO_RENAME_OK): New.
	* config/h8300/h8300.c (h8300_hard_regno_rename_ok): New.

From-SVN: r71119

gcc/ChangeLog

+2003-09-05  Nitin Yewale  <NitinY@KPITCummins.com>
+
+	* config/h8300/h8300-protos.h: Declare h8300_hard_regno_rename_ok
+	* config/h8300/h8300.h (HARD_REGNO_RENAME_OK): New.
+	* config/h8300/h8300.c (h8300_hard_regno_rename_ok): New.
+
 2003-09-05  Roger Sayle  <roger@eyesopen.com>
 	    Richard Henderson  <rth@redhat.com>
 

gcc/config/h8300/h8300-protos.h

@@ -98,6 +98,7 @@ extern void h8300_expand_prologue (void);
 extern void h8300_expand_epilogue (void);
 extern int h8300_current_function_interrupt_function_p (void);
 extern int h8300_initial_elimination_offset (int, int);
+extern int h8300_hard_regno_rename_ok (unsigned int, unsigned int);
 
 struct cpp_reader;
 extern void h8300_pr_interrupt (struct cpp_reader *);

gcc/config/h8300/h8300.c

@@ -4489,6 +4489,23 @@ same_cmp_preceding_p (rtx i3)
   return (INSN_P (i1) && rtx_equal_p (PATTERN (i1), PATTERN (i3))
 	  && any_condjump_p (i2) && onlyjump_p (i2));
 }
+
+/* Return nonzero if register OLD_REG can be renamed to register NEW_REG.  */
+
+int
+h8300_hard_regno_rename_ok (unsigned int old_reg ATTRIBUTE_UNUSED,
+			    unsigned int new_reg)
+{
+  /* Interrupt functions can only use registers that have already been
+     saved by the prologue, even if they would normally be
+     call-clobbered.  */
+
+  if (h8300_current_function_interrupt_function_p ()
+      && !regs_ever_live[new_reg])
+    return 0;
+
+   return 1;
+}
 
 /* Initialize the GCC target structure.  */
 #undef TARGET_ATTRIBUTE_TABLE

gcc/config/h8300/h8300.h

@@ -350,6 +350,12 @@ extern int target_flags;
        &&  ((MODE2) == QImode || (MODE2) == HImode			  \
 	    || ((TARGET_H8300H || TARGET_H8300S) && (MODE2) == SImode))))
 
+/* A C expression that is nonzero if hard register NEW_REG can be
+   considered for use as a rename register for OLD_REG register */
+
+#define HARD_REGNO_RENAME_OK(OLD_REG, NEW_REG)		\
+   h8300_hard_regno_rename_ok (OLD_REG, NEW_REG)
+
 /* Specify the registers used for certain standard purposes.
    The values of these macros are register numbers.  */