public inbox for gcc-prs@sourceware.org help / color / mirror / Atom feed
From: Richard Earnshaw <rearnsha@arm.com> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, Subject: Re: target/7056: [ARM] zero extend code worse in 3.1 than 3.0 Date: Mon, 17 Jun 2002 09:37:00 -0000 [thread overview] Message-ID: <20020617152604.30299.qmail@sources.redhat.com> (raw) The following reply was made to PR target/7056; it has been noted by GNATS. From: Richard Earnshaw <rearnsha@arm.com> To: pb@nexus.co.uk Cc: gcc-gnats@gcc.gnu.org, Richard.Earnshaw@arm.com, jakub@gcc.gnu.org, mark@codesourcery.com Subject: Re: target/7056: [ARM] zero extend code worse in 3.1 than 3.0 Date: Mon, 17 Jun 2002 16:21:06 +0100 This was caused by Jakub's patch to fix pr/6086, hence the CC list. I think his patch is papering over a symptom rather than fixing the real problem in reload. That is, if you are going to allow (subreg (mem)) at all, then reload must handle it correctly, even if the mem has side-effects. In this case we should be making reload correctly spill the mem, rather than preventing the above RTL if the mem has side-effects. For a RISC architecture, like the PPC, I don't think it makes sense to allow subreg-mem in the first place. The ARM doesn't and I've generally found this to lead to better code than allowing it and then letting reload fix up the problems. In general these problems seem to come about because register_operand() allows subreg(reg-or-mem) and that seems daft. R.
next reply other threads:[~2002-06-17 15:26 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-06-17 9:37 Richard Earnshaw [this message] -- strict thread matches above, loose matches on Subject: below -- 2002-06-17 7:00 pb
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=20020617152604.30299.qmail@sources.redhat.com \ --to=rearnsha@arm.com \ --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).