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Try to update dominance info in tree-call-cdce.c 

The pass would free the dominance info after making a change, but it
should be pretty easy to keep the information up-to-date when the call
has no EH edges.

Tested on x86_64-linux-gnu, arm-linux-gnueabi and aarch64-linux-gnu.

gcc/
	* tree-call-cdce.c (shrink_wrap_one_built_in_call): Try to update
	the dominance info; free it if we can't.
	(pass_call_cdce::execute): Don't free the dominance info here.

From-SVN: r229916
This commit is contained in:
Richard Sandiford 2015-11-07 09:56:04 +00:00 committed by Richard Sandiford
parent 88419b5295
commit f127ea514d
2 changed files with 42 additions and 1 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2015-11-07 Richard Sandiford <richard.sandiford@arm.com>
* tree-call-cdce.c (shrink_wrap_one_built_in_call): Try to update
the dominance info; free it if we can't.
(pass_call_cdce::execute): Don't free the dominance info here.
2015-11-06 Jeff Law <jeff@redhat.com>
* tree-ssa-threadedge.c (dummy_simplify): Remove.

37
gcc/tree-call-cdce.c
View File

@ -731,6 +731,32 @@ shrink_wrap_one_built_in_call (gcall *bi_call)
if (nconds == 0)
return false;
/* The cfg we want to create looks like this:
[guard n-1] <- guard_bb (old block)
| \
| [guard n-2] }
| / \ }
| / ... } new blocks
| / [guard 0] }
| / / | }
[ call ] | <- bi_call_bb }
| \ |
| \ |
| [ join ] <- join_tgt_bb (old iff call must end bb)
|
possible EH edges (only if [join] is old)
When [join] is new, the immediate dominators for these blocks are:
1. [guard n-1]: unchanged
2. [call]: [guard n-1]
3. [guard m]: [guard m+1] for 0 <= m <= n-2
4. [join]: [guard n-1]
We punt for the more complex case case of [join] being old and
simply free the dominance info. We also punt on postdominators,
which aren't expected to be available at this point anyway. */
bi_call_bb = gimple_bb (bi_call);
/* Now find the join target bb -- split bi_call_bb if needed. */
@ -741,6 +767,7 @@ shrink_wrap_one_built_in_call (gcall *bi_call)
join_tgt_in_edge_from_call = find_fallthru_edge (bi_call_bb->succs);
if (join_tgt_in_edge_from_call == NULL)
return false;
free_dominance_info (CDI_DOMINATORS);
}
else
join_tgt_in_edge_from_call = split_block (bi_call_bb, bi_call);
@ -820,6 +847,15 @@ shrink_wrap_one_built_in_call (gcall *bi_call)
guard_bb_in_edge->count = guard_bb->count - bi_call_in_edge->count;
}
if (dom_info_available_p (CDI_DOMINATORS))
{
/* The split_blocks leave [guard 0] as the immediate dominator
of [call] and [call] as the immediate dominator of [join].
Fix them up. */
set_immediate_dominator (CDI_DOMINATORS, bi_call_bb, guard_bb);
set_immediate_dominator (CDI_DOMINATORS, join_tgt_bb, guard_bb);
}
if (dump_file && (dump_flags & TDF_DETAILS))
{
location_t loc;
@ -927,7 +963,6 @@ pass_call_cdce::execute (function *fun)
if (something_changed)
{
free_dominance_info (CDI_DOMINATORS);
free_dominance_info (CDI_POST_DOMINATORS);
/* As we introduced new control-flow we need to insert PHI-nodes
for the call-clobbers of the remaining call. */