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From: "mkretz at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/85048] [missed optimization] vector conversions Date: Mon, 22 Apr 2024 08:21:07 +0000 [thread overview] Message-ID: <bug-85048-4-WTUUcB5qPg@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-85048-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85048 --- Comment #15 from Matthias Kretz (Vir) <mkretz at gcc dot gnu.org> --- So it seems that if at least one of the vector builtins involved in the expression is 512 bits GCC needs to locally increase prefer-vector-width to 512? Or, more generally: prefer-vector-width = max(prefer-vector-width, 8 * sizeof(operands)..., 8 * sizeof(return-value)) The reason to default to 256 bits is to avoid zmm register usage altogether (clock-down). But if the surrounding code already uses zmm registers that motivation is moot. Also, I think this shouldn't be considered auto-vectorization but rather pattern recognition (recognizing a __builtin_convertvector).
next prev parent reply other threads:[~2024-04-22 8:21 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-85048-4@http.gcc.gnu.org/bugzilla/> 2023-03-21 20:07 ` mkretz at gcc dot gnu.org 2023-03-22 1:25 ` crazylht at gmail dot com 2023-03-22 1:40 ` crazylht at gmail dot com 2023-03-22 2:10 ` crazylht at gmail dot com 2023-03-31 1:04 ` cvs-commit at gcc dot gnu.org 2023-03-31 1:07 ` crazylht at gmail dot com 2023-03-31 7:28 ` ubizjak at gmail dot com 2024-04-19 13:49 ` mkretz at gcc dot gnu.org 2024-04-22 0:37 ` liuhongt at gcc dot gnu.org 2024-04-22 8:21 ` mkretz at gcc dot gnu.org [this message] 2024-04-22 11:52 ` liuhongt at gcc dot gnu.org
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