reload1.c (eliminate_regs_in_insn): Recognize frame pointer adjustments even if...

* reload1.c (eliminate_regs_in_insn): Recognize frame pointer
adjustments even if they are implemented by more than two insns.

From-SVN: r49221

gcc/ChangeLog

+2002-01-25  Ulrich Weigand  <uweigand@de.ibm.com>
+
+	* reload1.c (eliminate_regs_in_insn): Recognize frame pointer
+	adjustments even if they are implemented by more than two insns.
+
 Fri Jan 25 20:43:56 CET 2002  Jan Hubicka  <jh@suse.cz>
 
 	* df.c (df_ref_create, df_ref_record_1, df_ref_record): Kill BB argument.

gcc/reload1.c

@@ -2932,38 +2932,32 @@ eliminate_regs_in_insn (insn, replace)
 	    if (ep->from == FRAME_POINTER_REGNUM
 		&& ep->to == HARD_FRAME_POINTER_REGNUM)
 	      {
-		rtx src = SET_SRC (old_set);
-		int offset = 0, ok = 0;
-		rtx prev_insn, prev_set;
-
-		if (src == ep->to_rtx)
-		  offset = 0, ok = 1;
-		else if (GET_CODE (src) == PLUS
-			 && GET_CODE (XEXP (src, 0)) == CONST_INT
-			 && XEXP (src, 1) == ep->to_rtx)
-		  offset = INTVAL (XEXP (src, 0)), ok = 1;
-		else if (GET_CODE (src) == PLUS
-			 && GET_CODE (XEXP (src, 1)) == CONST_INT
-			 && XEXP (src, 0) == ep->to_rtx)
-		  offset = INTVAL (XEXP (src, 1)), ok = 1;
-		else if ((prev_insn = prev_nonnote_insn (insn)) != 0
-			 && (prev_set = single_set (prev_insn)) != 0
-			 && rtx_equal_p (SET_DEST (prev_set), src))
+		rtx base = SET_SRC (old_set);
+		rtx base_insn = insn;
+		int offset = 0;
+
+		while (base != ep->to_rtx)
 		  {
-		    src = SET_SRC (prev_set);
-		    if (src == ep->to_rtx)
-		      offset = 0, ok = 1;
-		    else if (GET_CODE (src) == PLUS
-			     && GET_CODE (XEXP (src, 0)) == CONST_INT
-			     && XEXP (src, 1) == ep->to_rtx)
-		      offset = INTVAL (XEXP (src, 0)), ok = 1;
-		    else if (GET_CODE (src) == PLUS
-			     && GET_CODE (XEXP (src, 1)) == CONST_INT
-			     && XEXP (src, 0) == ep->to_rtx)
-		      offset = INTVAL (XEXP (src, 1)), ok = 1;
+		    rtx prev_insn, prev_set;
+
+		    if (GET_CODE (base) == PLUS
+		        && GET_CODE (XEXP (base, 1)) == CONST_INT)
+		      {
+		        offset += INTVAL (XEXP (base, 1));
+		        base = XEXP (base, 0);
+		      }
+		    else if ((prev_insn = prev_nonnote_insn (base_insn)) != 0
+			     && (prev_set = single_set (prev_insn)) != 0
+			     && rtx_equal_p (SET_DEST (prev_set), base))
+		      {
+		        base = SET_SRC (prev_set);
+		        base_insn = prev_insn;
+		      }
+		    else
+		      break;
 		  }
 
-		if (ok)
+		if (base == ep->to_rtx)
 		  {
 		    rtx src
 		      = plus_constant (ep->to_rtx, offset - ep->offset);