1 files changed, 1 insertions, 0 deletions
diff --git a/regalloc.c b/regalloc.c
index 2a878d0..1018e7c 100644
--- a/regalloc.c
+++ b/regalloc.c
@@ -33,6 +33,7 @@ readvar(struct bitset *defined, enum irclass cls, int var, struct block *blk)
    union ref val;
 
    if (bstest(defined, var)) return mkref(RTMP, var);
+   assert(cls && "?");
 
    /* memoed definition */
    if (xbcap(curdefs) > blk->id && xbcap(curdefs[blk->id]) > var && curdefs[blk->id][var])