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[Bug middle-end/77568] [7 regression] CSE/PRE/Hoisting blocks common instruction contractions
- From: "wdijkstr at arm dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 12 Sep 2016 18:11:15 +0000
- Subject: [Bug middle-end/77568] [7 regression] CSE/PRE/Hoisting blocks common instruction contractions
- Auto-submitted: auto-generated
- References: <bug-77568-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77568
--- Comment #3 from Wilco <wdijkstr at arm dot com> ---
(In reply to Andrew Pinski from comment #1)
> I think this is just a pass ordering issue. We create fmas after PRE.
> Maybe we should do it both before and after ...
> Or enhance the pass which produces FMA to walk through to another bb ...
FMAs are not created in the tree, Expand can do simple cases, and Combine finds
other cases. Given more and more targets support FMA, there is certainly an
argument for adding an FMA tree operator.