public inbox for gcc-prs@sourceware.org help / color / mirror / Atom feed
From: "Christian Ehrhardt" <ehrhardt@mathematik.uni-ulm.de> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, Subject: Re: c/8639: [3.2/3.3 regression] simple integer arithmetic expression broken Date: Tue, 26 Nov 2002 12:06:00 -0000 [thread overview] Message-ID: <20021119181611.24087.qmail@sources.redhat.com> (raw) The following reply was made to PR c/8639; it has been noted by GNATS. From: "Christian Ehrhardt" <ehrhardt@mathematik.uni-ulm.de> To: gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org, steveJepsen@netscape.net, gcc-bugs@gcc.gnu.org, nobody@gcc.gnu.org Cc: Subject: Re: c/8639: [3.2/3.3 regression] simple integer arithmetic expression broken Date: Tue, 19 Nov 2002 19:09:59 +0100 Hi, this patch will be bootstrapping here in a minute. An non bootstapped compile indicates that this fixes the bug. I'm not sure if we can be more clever here without doing a big rewrite of fold-const.c. I'll report back tonight/tomorrow (CET) when the testsuite has completed. Someone please consider to check this in. I don't have CVS access. Also adding a testcase would probably be a good idea. regards Christian --- gcc-3.2.1-20021111/gcc/fold-const.c.orig Tue Nov 19 18:47:57 2002 +++ gcc-3.2.1-20021111/gcc/fold-const.c Tue Nov 19 18:57:04 2002 @@ -4617,10 +4617,12 @@ t2 = extract_muldiv (op1, c, code, wide_type); if (t1 != 0 && t2 != 0 && (code == MULT_EXPR - /* If not multiplication, we can only do this if either operand - is divisible by c. */ - || multiple_of_p (ctype, op0, c) - || multiple_of_p (ctype, op1, c))) + /* If not multiplication, we can only do this if this is + * PLUS_EXPR and both operands are divisible by c. Note that + * (80 - 4*x)/20 or (80 + (-4)*x)/20 must not degenerate + * into (20 - x/5). */ + || (multiple_of_p (ctype, op0, c) && + multiple_of_p (ctype, op1, c)))) return fold (build (tcode, ctype, convert (ctype, t1), convert (ctype, t2))); http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8639 -- THAT'S ALL FOLKS!
next reply other threads:[~2002-11-19 18:16 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-11-26 12:06 Christian Ehrhardt [this message] -- strict thread matches above, loose matches on Subject: below -- 2002-11-25 21:06 bangerth
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=20021119181611.24087.qmail@sources.redhat.com \ --to=ehrhardt@mathematik.uni-ulm.de \ --cc=gcc-prs@gcc.gnu.org \ --cc=nobody@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: linkBe 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).