(use_regs): Change from USE and CLOBBER insns to using

CALL_INSN_FUNCTION_USAGE.

From-SVN: r7241

gcc/expr.h

@@ -596,8 +596,11 @@ extern void move_block_to_reg PROTO((int, rtx, int, enum machine_mode));
    The number of registers to be filled is NREGS.  */
 extern void move_block_from_reg PROTO((int, rtx, int, int));
 
-/* Mark NREGS consecutive regs, starting at REGNO, as being live now.  */
-extern void use_regs PROTO((int, int));
+/* Mark REG as holding a parameter for the next CALL_INSN.  */
+extern void use_reg PROTO((rtx*, rtx));
+/* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
+   for the next CALL_INSN.  */
+extern void use_regs PROTO((rtx*, rtx, int, int));
 
 /* Write zeros through the storage of OBJECT.
    If OBJECT has BLKmode, SIZE is its length in bytes.  */