From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: Christopher Li <sparse@chrisli.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Sparse Mailing-list <linux-sparse@vger.kernel.org>
Subject: Re: [PATCH v5 04/14] rewrite compare_opcode() like swap_compare_opcode()
Date: Mon, 27 Mar 2017 18:29:09 +0200 [thread overview]
Message-ID: <20170327162909.zvdl4ohcicprbdlm@macpro.local> (raw)
In-Reply-To: <CANeU7Qm_6_PtvOE=WpubgPgyo7SSGXvX3j8rq5m4UzR1EiHxQQ@mail.gmail.com>
On Sat, Mar 25, 2017 at 04:35:39PM -0700, Christopher Li wrote:
> On Fri, Mar 24, 2017 at 4:54 PM, Luc Van Oostenryck
> <luc.vanoostenryck@gmail.com> wrote:
> > Yes, indeed.
> > I've some plan to add better handling of floating-point and the compare
> > is part of it. It'll need a new set of instructions to do it correctly
> > (precisely
> > because for fp numbers once you care about NaNs/unordered "a < b" is *not*
> > the same as "!(a >= b)").
> > But there is also a number of bugs I want to solve, especially one related to
> > the misplacement of phi-node and another about missing reloads. For the moment
> > I think we can pretend that all the fp values we deal with are ordered ones.
>
> Can we detect it is the floating point type then avoid doing the
> compare swap for floating point?
We were not talking about the swap here but of the 'negate'
(and the swaping of the operands is immune to the NaNs/unordered).
And in fact, the code which needs the negation of compare's opcode
can't be called with floating-points args as this code is part of
the simplification made when one of the argument is a constant
(and only if the constant is 0 or 1). And by constant we mean here
a PSEUDO_VAL, which can never be part of a floating-point operation.
So in no cases can we have a problem because of that.
-- Luc
next prev parent reply other threads:[~2017-03-27 16:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-24 23:14 [PATCH 00/14] prepare LLVM fixes Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 01/14] don't output value of anonymous symbol's pointer Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 02/14] canonicalize binops before simplification Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 03/14] canonicalize compare instructions Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 04/14] rewrite compare_opcode() like swap_compare_opcode() Luc Van Oostenryck
2017-03-24 23:24 ` Linus Torvalds
2017-03-24 23:54 ` Luc Van Oostenryck
2017-03-25 23:35 ` Christopher Li
2017-03-26 0:22 ` Luc Van Oostenryck
2017-03-27 16:29 ` Luc Van Oostenryck [this message]
2017-03-24 23:14 ` [PATCH v5 05/14] add is_signed_type() Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 06/14] fix usage of inlined calls Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 07/14] inlined calls should not block BB packing Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 08/14] give function's arguments a type via OP_PUSH Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 09/14] insure that all OP_PUSHs are just before their OP_CALL Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 10/14] give a type to OP_PHISOURCEs Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 11/14] give a type to OP_SELs, always Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 12/14] give a type to OP_SWITCHs Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 13/14] add doc about sparse's instructions/IR Luc Van Oostenryck
2017-03-24 23:14 ` [PATCH v5 14/14] add support for wider type in switch-case Luc Van Oostenryck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170327162909.zvdl4ohcicprbdlm@macpro.local \
--to=luc.vanoostenryck@gmail.com \
--cc=linux-sparse@vger.kernel.org \
--cc=sparse@chrisli.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox