Fix alpha-linux GNU libc build failures.

	* combine.c (try_combine): When setting elim_i2, check whether newi2pat
	sets i2dest.  When calling distribute_notes for i3dest_killed, pass
	elim_i2 and elim_i1.  When setting elim_i1, check if newi2pat
	sets i1dest.

From-SVN: r16334

gcc/ChangeLog

@@ -6,6 +6,11 @@ Tue Nov  4 18:49:42 1997  Jeffrey A Law  (law@cygnus.com)
 
 Tue Nov  4 16:55:11 1997  Jim Wilson  <wilson@cygnus.com>
 
+	* combine.c (try_combine): When setting elim_i2, check whether newi2pat
+	sets i2dest.  When calling distribute_notes for i3dest_killed, pass
+	elim_i2 and elim_i1.  When setting elim_i1, check if newi2pat
+	sets i1dest.
+
 	* mips.md (insv, extzv, extv): Add change_address call.
 	(movsi_ulw, movsi_usw): Change QImode to BLKmode in pattern.
 

gcc/combine.c

@@ -2146,10 +2146,15 @@ try_combine (i3, i2, i1)
     rtx i3links, i2links, i1links = 0;
     rtx midnotes = 0;
     register int regno;
-    /* Compute which registers we expect to eliminate.  */
-    rtx elim_i2 = (newi2pat || i2dest_in_i2src || i2dest_in_i1src
+    /* Compute which registers we expect to eliminate.  newi2pat may be setting
+       either i3dest or i2dest, so we must check it.  Also, i1dest may be the
+       same as i3dest, in which case newi2pat may be setting i1dest.  */
+    rtx elim_i2 = ((newi2pat && reg_set_p (i2dest, newi2pat))
+		   || i2dest_in_i2src || i2dest_in_i1src
 		   ? 0 : i2dest);
-    rtx elim_i1 = i1 == 0 || i1dest_in_i1src ? 0 : i1dest;
+    rtx elim_i1 = (i1 == 0 || i1dest_in_i1src
+		   || (newi2pat && reg_set_p (i1dest, newi2pat))
+		   ? 0 : i1dest);
 
     /* Get the old REG_NOTES and LOG_LINKS from all our insns and
        clear them.  */
@@ -2312,12 +2317,12 @@ try_combine (i3, i2, i1)
 	if (newi2pat && reg_set_p (i3dest_killed, newi2pat))
 	  distribute_notes (gen_rtx (EXPR_LIST, REG_DEAD, i3dest_killed,
 				     NULL_RTX),
-			    NULL_RTX, i2, NULL_RTX, NULL_RTX, NULL_RTX);
+			    NULL_RTX, i2, NULL_RTX, elim_i2, elim_i1);
 	else
 	  distribute_notes (gen_rtx (EXPR_LIST, REG_DEAD, i3dest_killed,
 				     NULL_RTX),
 			    NULL_RTX, i3, newi2pat ? i2 : NULL_RTX,
-			    NULL_RTX, NULL_RTX);
+			    elim_i2, elim_i1);
       }
 
     if (i2dest_in_i2src)