public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/58416] Incorrect x87-based union copying code Date: Mon, 16 Sep 2013 10:28:00 -0000 [thread overview] Message-ID: <bug-58416-4-TZX9ZMZ9aJ@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-58416-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58416 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target| |i?86-*-* --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- It is SRA that transforms MCOp.DoubleVal = 0.0; MCOp.IntVal = Val_3(D); *dest_5(D) = MCOp; into MCOp$DoubleVal_7 = 0.0; _8 = VIEW_CONVERT_EXPR<double>(Val_3(D)); MCOp$DoubleVal_4 = _8; MEM[(union MyClass *)dest_5(D)] = MCOp$DoubleVal_4; simplifying into _6 = VIEW_CONVERT_EXPR<double>(Val_3(D)); MEM[(union MyClass *)dest_4(D)] = _6; and (insn 7 6 0 (set (mem:DF (reg/v/f:SI 60 [ dest ]) [0 MEM[(union MyClass *)dest_4(D)]+0 S8 A32]) (subreg:DF (reg/v:DI 61 [ Val ]) 0)) t.C:15 -1 (nil)) causes a reload: (insn 7 11 12 2 (set (reg:DF 8 st [62]) (mem/c:DF (plus:SI (reg/f:SI 7 sp) (const_int 8 [0x8])) [0 Val+0 S8 A32])) t.C:15 134 {*movdf_internal} (nil)) (insn 12 7 0 2 (set (mem:DF (reg/v/f:SI 0 ax [orig:60 dest ] [60]) [0 MEM[(union MyClass *)dest_4(D)]+0 S8 A32]) (reg:DF 8 st [62])) t.C:15 134 {*movdf_internal} (expr_list:REG_DEAD (reg:DF 8 st [62]) (expr_list:REG_DEAD (reg/v/f:SI 0 ax [orig:60 dest ] [60]) (nil)))) where *movdf_internal simply doesn't properly preserve sNaN. It looks wrong for DFmode move instructions to not preserve a IEEE defined flag. I suppose it would be also wrong to not preserve the exact bit pattern (think of canonicalizing NaNs).
next prev parent reply other threads:[~2013-09-16 10:28 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-09-13 19:56 [Bug target/58416] New: " stichnot at google dot com 2013-09-13 20:23 ` [Bug target/58416] " hjl.tools at gmail dot com 2013-09-16 10:28 ` rguenth at gcc dot gnu.org [this message] 2013-09-16 13:21 ` ubizjak at gmail dot com 2013-09-16 15:49 ` joseph at codesourcery dot com 2024-02-20 10:05 ` rguenth at gcc dot gnu.org 2024-02-20 10:07 ` rguenth at gcc dot gnu.org 2024-02-20 10:12 ` pinskia 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-58416-4-TZX9ZMZ9aJ@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: 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).