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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/99409] s252 benchmark of TSVC is vectorized by clang and not by gcc Date: Mon, 08 Mar 2021 08:23:21 +0000 [thread overview] Message-ID: <bug-99409-4-cZLL5dEMj9@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-99409-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99409 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |missed-optimization Blocks| |53947 Component|middle-end |tree-optimization --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Yes, we can't do 'scalar expansion'. We'd need some pre-pass to turn PHIs into data accesses. Here we want t[0] = (real_t) 0.; for (int i = 0; i < LEN_1D; i++) { s = b[i] * c[i]; a[i] = s + t[i]; t[i+1] = s; } and then of course the trick is to elide the actual array and instead do clever shuffling of vector registers instead. IIRC one of the other TSVC examples was similar. Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947 [Bug 53947] [meta-bug] vectorizer missed-optimizations
next prev parent reply other threads:[~2021-03-08 8:23 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-05 14:23 [Bug middle-end/99409] New: " hubicka at gcc dot gnu.org 2021-03-08 8:23 ` rguenth at gcc dot gnu.org [this message] 2022-10-17 10:36 ` [Bug tree-optimization/99409] " cvs-commit at gcc dot gnu.org 2022-10-17 10:40 ` rguenth at gcc dot gnu.org
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