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tree-ssa-threadedge.c (thread_around_empty_block): Remove checks for the number of predecessors and successors allowed.

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* tree-ssa-threadedge.c (thread_around_empty_block): Remove
        checks for the number of predecessors and successors allowed.
        * tree-ssa-threadupdate.c (mark_threaded_blocks): Ignore requests
        which require copying a joiner block if there is a request which
        is a subpath that requires no joiner block copying.

From-SVN: r202054
This commit is contained in:
Jeff Law 2013-08-28 09:07:45 -06:00 • committed by Jeff Law
parent 184799e763
commit 34554d1a8f
3 changed files with 52 additions and 13 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2013-08-28 Jeff Law <law@redhat.com>
* tree-ssa-threadedge.c (thread_around_empty_block): Remove
checks for the number of predecessors and successors allowed.
* tree-ssa-threadupdate.c (mark_threaded_blocks): Ignore requests
which require copying a joiner block if there is a request which
is a subpath that requires no joiner block copying.
2013-08-28 Jan Hubicka <jh@suse.cz>
* lto-streamer-out.c (DFS_write_tree_body): Drop

8
gcc/tree-ssa-threadedge.c
View file

@ -761,14 +761,6 @@ thread_around_empty_block (edge taken_edge,
gimple stmt;
tree cond;
/* This block must have a single predecessor (E->dest). */
if (!single_pred_p (bb))
return NULL;
/* This block must have more than one successor. */
if (single_succ_p (bb))
return NULL;
/* This block can have no PHI nodes. This is overly conservative. */
if (!gsi_end_p (gsi_start_phis (bb)))
return NULL;

49
gcc/tree-ssa-threadupdate.c
View file

@ -1146,17 +1146,56 @@ mark_threaded_blocks (bitmap threaded_blocks)
edge e;
edge_iterator ei;
/* It is possible to have jump threads in which one is a subpath
of the other. ie, (A, B), (B, C), (C, D) where B is a joiner
block and (B, C), (C, D) where no joiner block exists.
When this occurs ignore the jump thread request with the joiner
block. It's totally subsumed by the simpler jump thread request.
This results in less block copying, simpler CFGs. More improtantly,
when we duplicate the joiner block, B, in this case we will create
a new threading opportunity that we wouldn't be able to optimize
until the next jump threading iteration.
So first convert the jump thread requests which do not require a
joiner block. */
for (i = 0; i < threaded_edges.length (); i += 3)
{
edge e = threaded_edges[i];
edge *x = XNEWVEC (edge, 2);
e->aux = x;
THREAD_TARGET (e) = threaded_edges[i + 1];
THREAD_TARGET2 (e) = threaded_edges[i + 2];
bitmap_set_bit (tmp, e->dest->index);
if (threaded_edges[i + 2] == NULL)
{
edge *x = XNEWVEC (edge, 2);
e->aux = x;
THREAD_TARGET (e) = threaded_edges[i + 1];
THREAD_TARGET2 (e) = NULL;
bitmap_set_bit (tmp, e->dest->index);
}
}
/* Now iterate again, converting cases where we threaded through
a joiner block, but ignoring those where we have already
threaded through the joiner block. */
for (i = 0; i < threaded_edges.length (); i += 3)
{
edge e = threaded_edges[i];
if (threaded_edges[i + 2] != NULL
&& threaded_edges[i + 1]->aux == NULL)
{
edge *x = XNEWVEC (edge, 2);
e->aux = x;
THREAD_TARGET (e) = threaded_edges[i + 1];
THREAD_TARGET2 (e) = threaded_edges[i + 2];
bitmap_set_bit (tmp, e->dest->index);
}
}
/* If optimizing for size, only thread through block if we don't have
to duplicate it or it's an otherwise empty redirection block. */
if (optimize_function_for_size_p (cfun))