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From: "pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/18019] -march=pentium4 generates word fetch instead of byte fetch Date: Fri, 15 Oct 2004 18:12:00 -0000 [thread overview] Message-ID: <20041015181223.9854.qmail@sourceware.org> (raw) In-Reply-To: <20041015180025.18019.stuart@apple.com> ------- Additional Comments From pinskia at gcc dot gnu dot org 2004-10-15 18:12 ------- This is definitely a target problem, the RTL is correct: (insn:HI 23 22 24 (set (reg:QI 0 ax [orig:60 D.1459 ] [60]) (mem:QI (reg/v/f:SI 2 cx [orig:63 from ] [63]) [0 S1 A8])) 48 {*movqi_1} (nil) (nil)) I think the comment in i386.md summarizies the issues: ;; Situation is quite tricky about when to choose full sized (SImode) move ;; over QImode moves. For Q_REG -> Q_REG move we use full size only for ;; partial register dependency machines (such as AMD Athlon), where QImode ;; moves issue extra dependency and for partial register stalls machines ;; that don't use QImode patterns (and QImode move cause stall on the next ;; instruction). ;; ;; For loads of Q_REG to NONQ_REG we use full sized moves except for partial ;; register stall machines with, where we use QImode instructions, since ;; partial register stall can be caused there. Then we use movzx. -- What |Removed |Added ---------------------------------------------------------------------------- Component|c |target http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18019
next prev parent reply other threads:[~2004-10-15 18:12 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-10-15 18:00 [Bug c/18019] New: " stuart at apple dot com 2004-10-15 18:05 ` [Bug c/18019] " stuart at apple dot com 2004-10-15 18:12 ` pinskia at gcc dot gnu dot org [this message] 2004-10-15 18:23 ` [Bug target/18019] " pinskia at gcc dot gnu dot org 2004-10-15 18:27 ` stuart at apple dot com 2004-10-15 18:36 ` [Bug target/18019] [4.0 Regression] " pinskia at gcc dot gnu dot org 2004-10-28 15:19 ` steven at gcc dot gnu dot org 2004-10-28 15:22 ` steven at gcc dot gnu dot org 2004-11-09 4:50 ` pinskia at gcc dot gnu dot org 2004-11-09 18:10 ` roger at eyesopen dot com 2004-11-09 19:34 ` stuart at apple dot com 2004-11-09 20:56 ` roger at eyesopen dot com 2004-11-16 19:40 ` stuart at apple dot com 2004-11-27 18:28 ` neroden at gcc dot gnu dot org 2004-12-02 1:08 ` stuart at apple dot com 2004-12-02 3:35 ` neroden at gcc dot gnu dot org 2004-12-02 9:02 ` jh at suse dot cz 2004-12-10 17:09 ` neroden at gcc dot gnu dot org 2004-12-18 22:49 ` steven at gcc dot gnu dot org 2004-12-19 16:16 ` jh at suse dot cz 2004-12-19 19:58 ` pinskia at gcc dot gnu dot org 2004-12-22 12:20 ` steven at gcc dot gnu dot org 2004-12-30 13:16 ` cvs-commit at gcc dot gnu dot org 2004-12-30 13:21 ` steven at gcc dot gnu dot org
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