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[Bug tree-optimization/54742] Switch elimination in FSM loop
- From: "joey.ye at arm dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 10 Oct 2012 07:37:15 +0000
- Subject: [Bug tree-optimization/54742] Switch elimination in FSM loop
- Auto-submitted: auto-generated
- References: <bug-54742-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54742
--- Comment #3 from Joey Ye <joey.ye at arm dot com> 2012-10-10 07:37:15 UTC ---
Current jump-threading is too conservative to thread this case. Following
limits are what I observed by reading code:
1. It only thread around blocks that
* Single entry
* Multiple exit
* No PHI nodes
Even the simple case as forwarding block is excluded.
2. It only thread a block once. For blocks with more than one entries, it is
possible to be threaded more than one time too.