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From: "rdapp at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/114200] [14] RISC-V fixed-length vector miscompile at -O3 Date: Wed, 06 Mar 2024 12:55:09 +0000 [thread overview] Message-ID: <bug-114200-4-gsixfUByV3@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-114200-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114200 --- Comment #1 from Robin Dapp <rdapp at gcc dot gnu.org> --- Took me a while to analyze this... needed more time than I'd like to admit to make sense of the somewhat weird code created by fully unrolling and peeling. I believe the problem is that we reload the output register of a vfmacc/fma via vmv.v.v (subject to length masking) but we should be using vmv1r.v. The result is used by a reduction which always operates on the full length. As annoying as it was to find - it's definitely a good catch. I'm testing a patch. PR114202 is indeed a duplicate. Going to add its test case to the patch.
next prev parent reply other threads:[~2024-03-06 12:55 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-02 1:15 [Bug target/114200] New: " patrick at rivosinc dot com 2024-03-06 12:55 ` rdapp at gcc dot gnu.org [this message] 2024-03-06 19:42 ` [Bug target/114200] " cvs-commit at gcc dot gnu.org 2024-03-06 19:43 ` rdapp at gcc dot gnu.org 2024-03-07 0:31 ` patrick at rivosinc dot com 2024-03-07 5:39 ` pinskia at gcc dot gnu.org
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