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From: "rearnsha at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/55108] bad compile-time evaluation of members of initialized union Date: Tue, 30 Oct 2012 14:13:00 -0000 [thread overview] Message-ID: <bug-55108-4-aNNqgcWPfJ@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-55108-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55108 Richard Earnshaw <rearnsha at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2012-10-30 Ever Confirmed|0 |1 Known to fail| |4.6.3, 4.7.0 --- Comment #2 from Richard Earnshaw <rearnsha at gcc dot gnu.org> 2012-10-30 14:13:15 UTC --- Confirmed. It seems the compiler is incorrectly eliminating some zero-extend operations. We have Ra:SI = Rx:SI >> 8 Rb:QI = subreg:QI (Ra:SI 0) Rc:SI = subreg:SI (Rb:QI 0) Rd:SI = Rc:SI & 255 cse1 pass then decides incorrectly (and presumably because of the paradoxical subreg) that Rd == Rc and discards the mask operation. Also seen in 4.7, haven't been able to test trunk.
next prev parent reply other threads:[~2012-10-30 14:13 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-10-28 16:04 [Bug c/55108] New: " acn1 at cam dot ac.uk 2012-10-29 14:44 ` [Bug target/55108] " rguenth at gcc dot gnu.org 2012-10-30 14:13 ` rearnsha at gcc dot gnu.org [this message] 2012-10-30 14:16 ` rearnsha at gcc dot gnu.org 2013-02-03 23:25 ` mikpe at it dot uu.se 2013-02-04 0:06 ` pinskia at gcc dot gnu.org
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