Patch from Richard Henderson to make __builtin_return_address(0) work.

	* i386.h (RETURN_ADDR_RTX): New definition that works for
	__builtin_return_address(0) and -fomit-frame-pointer.

From-SVN: r15835

gcc/ChangeLog

+Thu Oct  2 21:15:03 1997  Richard Henderson  <rth@cygnus.com>
+
+	* i386.h (RETURN_ADDR_RTX): New definition that works for 
+	__builtin_return_address(0) and -fomit-frame-pointer.
+
 Wed Oct  1 13:43:53 1997  Jim Wilson  <wilson@cygnus.com>
 
 	Bring over from FSF.

gcc/config/i386/i386.h

@@ -2370,6 +2370,12 @@ number as al, and ax.
 #define INCOMING_RETURN_ADDR_RTX \
   gen_rtx (MEM, VOIDmode, gen_rtx (REG, VOIDmode, STACK_POINTER_REGNUM))
 
+/* After the prologue, RA is at -4(AP) in the current frame.  */
+#define RETURN_ADDR_RTX(COUNT, FRAME)					\
+  ((COUNT) == 0								\
+   ? gen_rtx (MEM, Pmode, gen_rtx (PLUS, Pmode, arg_pointer_rtx, GEN_INT(-4)))\
+   : gen_rtx (MEM, Pmode, gen_rtx (PLUS, Pmode, (FRAME), GEN_INT(4))))
+
 /* PC is dbx register 8; let's use that column for RA. */
 #define DWARF_FRAME_RETURN_COLUMN 	8