Store a destination step in the block descriptor

At the moment, this just saves a memory reference in the GC inner loop
(worth a percent or two of GC time).  Later, it will hopefully let me
experiment with partial steps, and simplifying the generation/step
infrastructure.

1 files changed, 1 insertions, 0 deletions

diff --git a/rts/Arena.c b/rts/Arena.c
index 7fc49f44d7..e636de4b9a 100644
--- a/rts/Arena.c
+++ b/rts/Arena.c
@@ -86,6 +86,7 @@ arenaAlloc( Arena *arena, size_t size )
 
 	bd->gen_no  = 0;
 	bd->step    = NULL;
+	bd->dest    = NULL;
 	bd->flags   = 0;
 	bd->free    = bd->start;
 	bd->link    = arena->current;