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re PR rtl-optimization/59446 (loop2_doloop creates constant comparison and dead jump)

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PR rtl-optimization/59446
	* tree-ssa-threadupdate.c (mark_threaded_blocks): Properly
	test for crossing a loop header.

From-SVN: r205905
This commit is contained in:
Jeff Law 2013-12-11 15:15:14 -07:00 committed by Jeff Law
parent 2608443287
commit 6d4fbcc9fd
2 changed files with 27 additions and 33 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2013-12-11 Jeff Law <law@redhat.com>
PR rtl-optimization/59446
* tree-ssa-threadupdate.c (mark_threaded_blocks): Properly
test for crossing a loop header.
2013-12-11 Sriraman Tallam <tmsriram@google.com>
PR target/59390

54
gcc/tree-ssa-threadupdate.c
View File

@ -1449,44 +1449,32 @@ mark_threaded_blocks (bitmap threaded_blocks)
{
vec<jump_thread_edge *> *path = THREAD_PATH (e);
/* Basically we're looking for a situation where we can see
3 or more loop structures on a jump threading path. */
struct loop *first_father = (*path)[0]->e->src->loop_father;
struct loop *second_father = NULL;
for (unsigned int i = 0; i < path->length (); i++)
for (unsigned int i = 0, crossed_headers = 0;
i < path->length ();
i++)
{
/* See if this is a loop father we have not seen before. */
if ((*path)[i]->e->dest->loop_father != first_father
&& (*path)[i]->e->dest->loop_father != second_father)
basic_block dest = (*path)[i]->e->dest;
crossed_headers += (dest == dest->loop_father->header);
if (crossed_headers > 1)
{
/* We've already seen two loop fathers, so we
need to trim this jump threading path. */
if (second_father != NULL)
{
/* Trim from entry I onwards. */
for (unsigned int j = i; j < path->length (); j++)
delete (*path)[j];
path->truncate (i);
/* Trim from entry I onwards. */
for (unsigned int j = i; j < path->length (); j++)
delete (*path)[j];
path->truncate (i);
/* Now that we've truncated the path, make sure
what's left is still valid. We need at least
two edges on the path and the last edge can not
be a joiner. This should never happen, but let's
be safe. */
if (path->length () < 2
|| (path->last ()->type
== EDGE_COPY_SRC_JOINER_BLOCK))
{
delete_jump_thread_path (path);
e->aux = NULL;
}
break;
}
else
/* Now that we've truncated the path, make sure
what's left is still valid. We need at least
two edges on the path and the last edge can not
be a joiner. This should never happen, but let's
be safe. */
if (path->length () < 2
|| (path->last ()->type
== EDGE_COPY_SRC_JOINER_BLOCK))
{
second_father = (*path)[i]->e->dest->loop_father;
delete_jump_thread_path (path);
e->aux = NULL;
}
break;
}
}
}