public inbox for gcc-cvs@sourceware.org
help / color / mirror / Atom feed
From: Pierre-Marie de Rodat <pmderodat@gcc.gnu.org>
To: gcc-cvs@gcc.gnu.org
Subject: [gcc r12-6452] [Ada] Adapt ghost code to maintain proof
Date: Tue, 11 Jan 2022 13:27:04 +0000 (GMT)	[thread overview]
Message-ID: <20220111132704.46B2638A9405@sourceware.org> (raw)

https://gcc.gnu.org/g:371b4ad7c423891d13f9b855f5fdd469a82f7160

commit r12-6452-g371b4ad7c423891d13f9b855f5fdd469a82f7160
Author: Yannick Moy <moy@adacore.com>
Date:   Tue Jan 4 10:37:53 2022 +0100

    [Ada] Adapt ghost code to maintain proof
    
    gcc/ada/
    
            * libgnat/s-expmod.adb (Exp_Modular): Add assertions.

Diff:
---
 gcc/ada/libgnat/s-expmod.adb | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gcc/ada/libgnat/s-expmod.adb b/gcc/ada/libgnat/s-expmod.adb
index 61faed16b25..60d86e505b8 100644
--- a/gcc/ada/libgnat/s-expmod.adb
+++ b/gcc/ada/libgnat/s-expmod.adb
@@ -278,6 +278,7 @@ is
                  (Big (Result) * Big (Factor) ** (Exp - 1),
                   Big (Left) ** Right));
                Lemma_Exp_Expand (Big (Factor), Exp - 1);
+               pragma Assert (Exp / 2 = (Exp - 1) / 2);
             end if;
 
             Lemma_Exp_Expand (Big (Factor), Exp);
@@ -286,6 +287,8 @@ is
             exit when Exp = 0;
 
             Rest := Big (Factor) ** Exp;
+            pragma Assert (Equal_Modulo
+              (Big (Result) * (Rest * Rest), Big (Left) ** Right));
             Lemma_Exp_Mod (Big (Factor) * Big (Factor), Exp, Big (Modulus));
             pragma Assert
               ((Big (Factor) * Big (Factor)) ** Exp = Rest * Rest);


                 reply	other threads:[~2022-01-11 13:27 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

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=20220111132704.46B2638A9405@sourceware.org \
    --to=pmderodat@gcc.gnu.org \
    --cc=gcc-cvs@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).