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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/99544] [11 Regression] ICE in expand_mult, at expmed.c:3582 Date: Fri, 12 Mar 2021 10:34:06 +0000 [thread overview] Message-ID: <bug-99544-4-Wu1UQxRmny@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-99544-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99544 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org, | |rguenth at gcc dot gnu.org --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I think this is another case that the PR98287 proposed patch would fix, again after vec lowering some pass (seems vrp2 in this case), this time it is the /* Canonicalize X + (X << C) into X * (1 + (1 << C)) and (X << C1) + (X << C2) into X * ((1 << C1) + (1 << C2)). */ match.pd rule, where the target apparently supports V2DImode left shift by scalar constant and addition, but doesn't support V2DImode multiplication. Maybe in this particular case it would be worth guarding the pattern on existing optab for vector multiplication or disable it for vectors altogether (apparently it was myself who has added that), because at least if the target doesn't have particular vector multiplications, I'd say doing the additions and shifts must be better than scalarizing it. If multiplications are supported, I guess best would be to let the expansion decide what is better, it has code to turn scalar multiplications by constant into additions and shifts, so perhaps could use that also for vector by uniform constants?
next prev parent reply other threads:[~2021-03-12 10:34 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-11 7:43 [Bug target/99544] New: " asolokha at gmx dot com 2021-03-11 8:45 ` [Bug target/99544] " rguenth at gcc dot gnu.org 2021-03-11 12:24 ` eochoa at gcc dot gnu.org 2021-03-12 10:34 ` jakub at gcc dot gnu.org [this message] 2021-03-12 10:48 ` [Bug tree-optimization/99544] " jakub at gcc dot gnu.org 2021-03-12 11:00 ` rguenth at gcc dot gnu.org 2021-03-12 11:00 ` jakub at gcc dot gnu.org 2021-03-12 11:38 ` rguenther at suse dot de 2021-03-13 8:00 ` cvs-commit at gcc dot gnu.org 2021-03-13 8:55 ` jakub at gcc dot gnu.org
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