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[Bug tree-optimization/54855] Unnecessary duplication when performing scalar operation on vector element
- From: "glisse at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sat, 20 Oct 2012 17:43:44 +0000
- Subject: [Bug tree-optimization/54855] Unnecessary duplication when performing scalar operation on vector element
- Auto-submitted: auto-generated
- References: <bug-54855-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54855
--- Comment #6 from Marc Glisse <glisse at gcc dot gnu.org> 2012-10-20 17:43:44 UTC ---
Uros' reply at http://gcc.gnu.org/ml/gcc-patches/2012-10/msg01327.html copied
here for convenience:
"But, we _do_ have vec_merge pattern that describes the operation.
Adding another one to each operation just to satisfy combine is IMO
not correct approach. I'd rather see generic RTX simplification that
simplifies your proposed pattern to vec_merge pattern. Also, as you
mention in PR54855, Comment #5, the approach is too fragile..."