--- gcc/tree-ssa-threadedge.c	(revision 194469)
+++ gcc/tree-ssa-threadedge.c	(working copy)
@@ -713,7 +713,7 @@ propagate_threaded_block_debug_into (bas
 	      if (i >= 0)
 		continue;
 
-	      if (fewvars.length () < alloc_count)
+	      if (fewvars.length () < (unsigned) alloc_count)
 		fewvars.quick_push (var);
 	      else
 		{