Small patch for complex moves

[Bernd Schmidt]

Here's a small patch that makes the compiler handle complex values like
any other multi-register values when moving them. This causes better flow
information to be generated. Previously, when returning a complex float on
the i386, the compiler used to think that eax and edx, which contain the
return value, are live throughout the function.

Bernd

	* expr.c (emit_move_insn_1): When moving complex values in several
	steps, emit a CLOBBER to show the destination dies.

Index: expr.c
===================================================================
RCS file: /usr/local/cvs/gcc/gcc/expr.c,v
retrieving revision 1.1.3.20
diff -p -r1.1.3.20 expr.c
*** expr.c	1998/02/16 19:03:51	1.1.3.20
--- expr.c	1998/02/19 12:10:17
*************** emit_move_insn_1 (x, y)
*** 2255,2260 ****
--- 2255,2264 ----
  	}
        else
  	{
+ 	  /* Show the output dies here.  */
+ 	  if (x != y)
+ 	    emit_insn (gen_rtx_CLOBBER (VOIDmode, x));
+ 
  	  emit_insn (GEN_FCN (mov_optab->handlers[(int) submode].insn_code)
  		     (gen_realpart (submode, x), gen_realpart (submode, y)));
  	  emit_insn (GEN_FCN (mov_optab->handlers[(int) submode].insn_code)