re PR middle-end/63155 (memory hog)

2018-09-14  Richard Biener  <rguenther@suse.de>

	PR middle-end/63155
	* tree-ssa-coalesce.c (ssa_conflicts_merge): Remove conflict
	bits for the merged partition.

From-SVN: r264304

gcc/ChangeLog

+2018-09-14  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/63155
+	* tree-ssa-coalesce.c (ssa_conflicts_merge): Remove conflict
+	bits for the merged partition.
+
 2018-09-13  Martin Sebor  <msebor@redhat.com>
 	    Bernd Edlinger  <bernd.edlinger@hotmail.de>
 

gcc/tree-ssa-coalesce.c

@@ -620,7 +620,11 @@ ssa_conflicts_merge (ssa_conflicts *ptr, unsigned x, unsigned y)
     {
       bitmap bz = ptr->conflicts[z];
       if (bz)
-	bitmap_set_bit (bz, x);
+	{
+	  bool was_there = bitmap_clear_bit (bz, y);
+	  gcc_checking_assert (was_there);
+	  bitmap_set_bit (bz, x);
+	}
     }
 
   if (bx)