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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/67830] [6 Regression] wrong code at -O1 and above on x86_64-linux-gnu Date: Mon, 05 Oct 2015 08:43:00 -0000 [thread overview] Message-ID: <bug-67830-4-3MK6xp36bv@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-67830-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67830 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |NEW CC| |law at gcc dot gnu.org --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- _7 = (int) _5; _10 = (int) d.2_9; f_11 = _10 - _7; _12 = f_11 & -2; with _5 and d.2_9 being of type unsigned char is transformed to _15 = d.2_9 - _5; _16 = _15 & 254; _12 = (int) _16; with _16 being unsigned char. That looks wrong as it changes a sign-extended subtraction result to a zero-extended one. CCing Jeff who added that pattern.
next prev parent reply other threads:[~2015-10-05 8:43 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-10-03 5:38 [Bug rtl-optimization/67830] New: " su at cs dot ucdavis.edu 2015-10-05 8:32 ` [Bug tree-optimization/67830] [6 Regression] " rguenth at gcc dot gnu.org 2015-10-05 8:43 ` rguenth at gcc dot gnu.org [this message] 2015-10-05 10:11 ` mpolacek at gcc dot gnu.org 2015-10-05 18:54 ` law at redhat dot com 2015-10-23 19:17 ` law at redhat dot com 2015-10-23 19:17 ` law at gcc dot gnu.org
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