+2013-11-18 Jeff Law <law@redhat.com>
+
+ * tree-ssa-threadupdate.c: Fix file block comment.
+ Fix minor indention issue.
+
2013-11-18 Uros Bizjak <ubizjak@gmail.com>
* config/i386/i386.c (ix86_decompose_address): Use REG_P instead of
set of unique destination blocks that the incoming edges should
be threaded to.
- Block duplication can be further minimized by using B instead of
- creating B' for one destination if all edges into B are going to be
- threaded to a successor of B. We had code to do this at one time, but
- I'm not convinced it is correct with the changes to avoid mucking up
- the loop structure (which may cancel threading requests, thus a block
- which we thought was going to become unreachable may still be reachable).
- This code was also going to get ugly with the introduction of the ability
- for a single jump thread request to bypass multiple blocks.
+ We reduce the number of edges and statements we create by not copying all
+ the outgoing edges and the control statement in step #1. We instead create
+ a template block without the outgoing edges and duplicate the template.
- We further reduce the number of edges and statements we create by
- not copying all the outgoing edges and the control statement in
- step #1. We instead create a template block without the outgoing
- edges and duplicate the template. */
+ Another case this code handles is threading through a "joiner" block. In
+ this case, we do not know the destination of the joiner block, but one
+ of the outgoing edges from the joiner block leads to a threadable path. This
+ case largely works as outlined above, except the duplicate of the joiner
+ block still contains a full set of outgoing edges and its control statement.
+ We just redirect one of its outgoing edges to our jump threading path. */
/* Steps #5 and #6 of the above algorithm are best implemented by walking
= new jump_thread_edge ((*path)[i]->e, (*path)[i]->type);
copy->safe_push (x);
}
- e->aux = (void *)copy;
+ e->aux = (void *)copy;
}
else
{