public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "jbeulich at suse dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/108941] Error: operand type mismatch for `shr' with binutils master
Date: Mon, 27 Feb 2023 10:57:54 +0000	[thread overview]
Message-ID: <bug-108941-4-merSjZ5fnT@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108941-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108941

--- Comment #6 from jbeulich at suse dot com ---
(In reply to Jakub Jelinek from comment #5)
> GCC doesn't even have that information at all, at the RTL level it doesn't
> know
> if it was signed or unsigned.
> All it has is the constraint and operand for it, like (reg:QI 126) or
> (const_int -1).
> As I said earlier, constants are always sign-extended from their mode.
> One could e.g. have during expansion (set (reg:QI 126) (const_int -1))
> and later on asm_operands with "ic" and (reg:QI 126).  Same assignment for
> int8_t x = -1 or int8_t x = 255 or uint8_t x = -1 or uint8_t x = 255, at
> GIMPLE one can differentiate that based on types, at RTL one has just mode.

While for int8_t x = -1 or int8_t x = 255 I can see that the result is as
described, for uint8_t x = -1 or uint8_t x = 255 (or, as in the example, a
constant the was cast to an unsigned 8-bit type) why is it not (const int 255)?

  parent reply	other threads:[~2023-02-27 10:57 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-27  9:39 [Bug c/108941] New: " marxin at gcc dot gnu.org
2023-02-27  9:51 ` [Bug c/108941] " jakub at gcc dot gnu.org
2023-02-27 10:00 ` marxin at gcc dot gnu.org
2023-02-27 10:07 ` jakub at gcc dot gnu.org
2023-02-27 10:17 ` jbeulich at suse dot com
2023-02-27 10:33 ` jakub at gcc dot gnu.org
2023-02-27 10:57 ` jbeulich at suse dot com [this message]
2023-02-27 11:00 ` jbeulich at suse dot com
2023-02-27 11:02 ` jakub at gcc dot gnu.org
2023-02-27 11:11 ` jbeulich at suse dot com
2023-02-27 11:14 ` jakub at gcc dot gnu.org
2023-02-27 11:17 ` jakub at gcc dot gnu.org
2023-02-27 11:17 ` marxin at gcc dot gnu.org
2023-02-27 11:23 ` jakub at gcc dot gnu.org
2023-02-28  7:33 ` jbeulich at suse dot com
2023-02-28  7:47 ` jakub at gcc dot gnu.org
2023-02-28  7:59 ` jbeulich at suse dot com
2023-02-28  8:10 ` jakub at gcc dot gnu.org

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=bug-108941-4-merSjZ5fnT@http.gcc.gnu.org/bugzilla/ \
    --to=gcc-bugzilla@gcc.gnu.org \
    --cc=gcc-bugs@gcc.gnu.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;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).