FIX_REGISTER_CHECK

[Gavin Romig-Koch <gavin at cygnus dot com>]

This patch implements an error message for the use of an invalid 
register in a -fcall-used-REG or -fcall-saved-REG option.

OK to commit to egcs?

                                    -gavin...



	* tm.texi (FIX_REGISTER_CHECK): New.
	* regclass.c (fix_register) : Use FIX_REGISTER_CHECK.

	* config/mips/mips.h (FIX_REGISTER_CHECK): Define.

Index: regclass.c
===================================================================
*************** fix_register (name, fixed, call_used)
*** 574,581 ****
  
    if ((i = decode_reg_name (name)) >= 0)
      {
!       fixed_regs[i] = fixed;
!       call_used_regs[i] = call_used;
      }
    else
      {
--- 574,595 ----
  
    if ((i = decode_reg_name (name)) >= 0)
      {
! #ifdef FIX_REGISTER_CHECK
!       if (! FIX_REGISTER_CHECK (i, fixed, call_used))
! 	{
! 	  static char* what_option[2][2] = {
! 	    "call-saved", "call-used", 
! 	    "no-such-option", "fixed" };
! 	  
! 	  error ("can't use '%s' as a %s register", name, 
! 		 what_option[fixed][call_used]);
! 	}
!       else
! #endif
! 	{
! 	  fixed_regs[i] = fixed;
! 	  call_used_regs[i] = call_used;
! 	}
      }
    else
      {
Index: tm.texi
===================================================================
*************** of the insn patterns whose constraints p
*** 1371,1376 ****
--- 1371,1382 ----
  controlled by target switches, then GCC will automatically avoid using
  these registers when the target switches are opposed to them.)
  
+ @findex FIX_REGISTER_CHECK
+ @item FIX_REGISTER_CHECK
+ If defined this macro is a boolean valued expression used to check
+ for invalid uses of -fcall-used-REG or -fcall-saved-REG.  It should
+ evaluate to false for invalid uses.  It need not be defined.
+ 
  @findex NON_SAVING_SETJMP
  @item NON_SAVING_SETJMP
  If this macro is defined and has a nonzero value, it means that
Index: config/mips/mips.h
===================================================================
*************** while (0)
*** 684,689 ****
--- 684,698 ----
  
  /* Show we can debug even without a frame pointer.  */
  #define CAN_DEBUG_WITHOUT_FP
+ 
+ /* Return false for invalid use of -fcall-used-REG or -fcall-saved-REG,
+    true otherwise. */
+ #define FIX_REGISTER_CHECK(NUMBER,FIXED,CALL_USED)			\
+      (! (((NUMBER) == HARD_FRAME_POINTER_REGNUM				\
+ 	|| (NUMBER) == STACK_POINTER_REGNUM)				\
+ 	 && (!(FIXED) && !(CALL_USED)					\
+ 	     || !(FIXED) && (CALL_USED))))
+ 
  
  /* Complain about missing specs and predefines that should be defined in each
     of the target tm files to override the defaults.  This is mostly a place-