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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/87555] There is no need for UNSPEC_FMADDSUB Date: Fri, 18 Jun 2021 07:00:26 +0000 [thread overview] Message-ID: <bug-87555-4-xlLegTpv6L@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-87555-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87555 --- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> --- I don't think there's a documented canonical form but if I were to write one I'd say the smaller (as in integer) merge mask should win? There might also be the argument that fma vs fms (or add vs sub in the addsub case) can be the tie-breaker. Note I'm not sure that doing fmaddsub as merge of fma and fms will be optimal since that most definitely will preclude combine from recognizing fmaddsub from (addsub (mul ..) x) which would be another goal to support (PR81904) I'm looking at merging the addsub patterns with the (const_int <mode-attr>) trick, but I'm struggling with alternatives - time to learn ;)
next prev parent reply other threads:[~2021-06-18 7:00 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-87555-4@http.gcc.gnu.org/bugzilla/> 2021-06-17 12:07 ` rguenth at gcc dot gnu.org 2021-06-18 1:22 ` crazylht at gmail dot com 2021-06-18 1:57 ` crazylht at gmail dot com 2021-06-18 5:40 ` crazylht at gmail dot com 2021-06-18 6:00 ` crazylht at gmail dot com 2021-06-18 6:02 ` crazylht at gmail dot com 2021-06-18 6:11 ` crazylht at gmail dot com 2021-06-18 6:34 ` crazylht at gmail dot com 2021-06-18 7:00 ` rguenth at gcc dot gnu.org [this message] 2021-06-18 7:09 ` crazylht at gmail dot com 2021-06-18 7:09 ` rguenth at gcc dot gnu.org 2021-06-18 7:11 ` rguenth at gcc dot gnu.org 2021-06-18 7:16 ` crazylht at gmail dot com 2021-06-18 7:32 ` rguenth at gcc dot gnu.org 2021-06-18 7:48 ` crazylht at gmail dot com 2021-06-18 10:29 ` rguenth at gcc dot gnu.org 2021-09-12 23:44 ` pinskia at gcc dot gnu.org
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