sh.h: Define HARD_REGNO_RENAME_OK

Fri Jun 14 12:04:02 2002  Dhananjay R. Deshpande <dhananjayd@kpit.com>

	* sh.h: Define HARD_REGNO_RENAME_OK
	* sh.c: sh_hard_regno_rename_ok: New. If current function has
	interrupt_handler attribute, only registers saved on stack are OK.
	* sh-protos.h: Declare sh_hard_regno_rename_ok.

From-SVN: r54612

gcc/ChangeLog

+Fri Jun 14 12:04:02 2002  Dhananjay R. Deshpande <dhananjayd@kpit.com>
+
+	* sh.h: Define HARD_REGNO_RENAME_OK
+	* sh.c: sh_hard_regno_rename_ok: New. If current function has
+	interrupt_handler attribute, only registers saved on stack are OK.
+	* sh-protos.h: Declare sh_hard_regno_rename_ok.
+
 2002-06-14  Kaz Kojima  <kkojima@gcc.gnu.org>
 
 	* config/sh/sh.md (jump): Emit jump insn.

gcc/config/sh/sh-protos.h

@@ -122,6 +122,7 @@ extern int sh_need_epilogue PARAMS ((void));
 extern int initial_elimination_offset PARAMS ((int, int));
 extern int fldi_ok PARAMS ((void));
 extern int sh_pr_n_sets PARAMS ((void));
+extern int sh_hard_regno_rename_ok PARAMS ((unsigned int, unsigned int));
 
 #ifdef HARD_CONST
 extern void fpscr_set_from_mem PARAMS ((int, HARD_REG_SET));

gcc/config/sh/sh.c

@@ -6701,6 +6701,26 @@ sh_can_redirect_branch (branch1, branch2)
   return 0;
 }
 
+/* Return non-zero if register old_reg can be renamed to register new_reg.  */
+int
+sh_hard_regno_rename_ok (old_reg, new_reg)
+     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 ((lookup_attribute ("interrupt_handler",
+			  DECL_ATTRIBUTES (current_function_decl))
+	!= NULL_TREE)
+       && !regs_ever_live[new_reg])
+     return 0;
+
+   return 1;
+}
+
 /* A C statement (sans semicolon) to update the integer variable COST
    based on the relationship between INSN that is dependent on
    DEP_INSN through the dependence LINK.  The default is to make no

gcc/config/sh/sh.h

@@ -942,6 +942,12 @@ extern char sh_additional_register_names[ADDREGNAMES_SIZE] \
 			      && (GET_MODE_SIZE (MODE2) <= 4)) \
 			  : ((MODE1) != SFmode && (MODE2) != SFmode))))
 
+/* 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) \
+   sh_hard_regno_rename_ok (OLD_REG, NEW_REG)
+
 /* Specify the registers used for certain standard purposes.
    The values of these macros are register numbers.  */