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From: "rsandifo at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/110751] RISC-V: Suport undefined value that allows VSETVL PASS use TA/MA Date: Thu, 20 Jul 2023 13:29:10 +0000 [thread overview] Message-ID: <bug-110751-4-AMd2KZFznZ@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-110751-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751 rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rsandifo at gcc dot gnu.org --- Comment #13 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- I understand the concern with undefined values, since it then becomes less obvious whether e.g.: a = undef b = a == a is guaranteed to be true, or whether it reduces to: b = undef == undef which is presumably undef. But I don't think a null operand really helps. The same question would apply to: x = COND_LEN_ADD (a, b, null, len, bias) y = x == x vs. x1 = COND_LEN_ADD (a, b, null, len, bias) x2 = COND_LEN_ADD (a, b, null, len, bias) y = x1 == x2 Do both of these ys evaluate to true, or is one or both be undefined? So if we're prepared to accept undefinedness, I'd prefer to have a “proper” representation of it. We could probably adopt LLVM's semantics for undef. (SVE might have some uses for this too.)
next prev parent reply other threads:[~2023-07-20 13:29 UTC|newest] Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-07-20 9:03 [Bug target/110751] New: " xuli1 at eswincomputing dot com 2023-07-20 9:10 ` [Bug target/110751] " juzhe.zhong at rivai dot ai 2023-07-20 9:30 ` rguenth at gcc dot gnu.org 2023-07-20 9:37 ` rguenth at gcc dot gnu.org 2023-07-20 9:58 ` kito at gcc dot gnu.org 2023-07-20 11:28 ` rguenther at suse dot de 2023-07-20 11:43 ` juzhe.zhong at rivai dot ai 2023-07-20 12:00 ` juzhe.zhong at rivai dot ai 2023-07-20 12:35 ` rguenther at suse dot de 2023-07-20 12:42 ` juzhe.zhong at rivai dot ai 2023-07-20 12:45 ` rguenther at suse dot de 2023-07-20 12:50 ` juzhe.zhong at rivai dot ai 2023-07-20 12:56 ` rguenther at suse dot de 2023-07-20 13:29 ` rsandifo at gcc dot gnu.org [this message] 2023-07-20 13:32 ` rguenther at suse dot de 2023-07-20 22:03 ` juzhe.zhong at rivai dot ai 2023-07-21 1:53 ` xuli1 at eswincomputing dot com 2023-07-21 6:17 ` rguenth at gcc dot gnu.org 2023-07-21 12:47 ` rsandifo at gcc dot gnu.org 2023-07-21 12:53 ` rguenth at gcc dot gnu.org 2023-07-21 13:23 ` rsandifo at gcc dot gnu.org 2023-07-24 6:20 ` rguenther at suse dot de 2023-07-25 7:05 ` juzhe.zhong at rivai dot ai 2023-09-12 11:44 ` juzhe.zhong at rivai dot ai 2023-09-12 14:24 ` rsandifo at gcc dot gnu.org 2023-09-12 14:53 ` juzhe.zhong at rivai dot ai 2023-09-12 15:59 ` rsandifo at gcc dot gnu.org 2023-09-12 16:21 ` juzhe.zhong at rivai dot ai 2023-09-12 16:27 ` juzhe.zhong at rivai dot ai 2023-09-12 16:31 ` juzhe.zhong at rivai dot ai 2023-09-12 22:44 ` juzhe.zhong at rivai dot ai 2023-09-13 7:56 ` rguenth at gcc dot gnu.org 2023-09-13 8:34 ` juzhe.zhong at rivai dot ai 2023-09-13 8:39 ` juzhe.zhong at rivai dot ai 2023-09-13 9:38 ` rguenth at gcc dot gnu.org 2023-09-13 9:39 ` rguenth at gcc dot gnu.org 2023-09-13 9:48 ` juzhe.zhong at rivai dot ai 2023-09-13 9:48 ` juzhe.zhong at rivai dot ai 2023-09-13 10:15 ` rguenther at suse dot de 2023-09-13 22:39 ` rsandifo at gcc dot gnu.org 2023-09-14 8:53 ` juzhe.zhong at rivai dot ai 2023-09-14 9:15 ` richard.sandiford at arm dot com 2023-09-20 16:27 ` cvs-commit at gcc dot gnu.org 2023-09-21 9:13 ` cvs-commit at gcc dot gnu.org 2023-09-21 9:28 ` juzhe.zhong at rivai dot ai 2023-09-22 7:31 ` xuli1 at eswincomputing dot com 2023-09-22 7:33 ` xuli1 at eswincomputing dot com
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