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From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/33887] [4.2/4.3 Regression] Reference to bitfield gets wrong value when optimizing Date: Tue, 11 Dec 2007 12:50:00 -0000 [thread overview] Message-ID: <20071211125033.23928.qmail@sourceware.org> (raw) In-Reply-To: <bug-33887-1313@http.gcc.gnu.org/bugzilla/> ------- Comment #7 from rguenth at gcc dot gnu dot org 2007-12-11 12:50 ------- Reduced testcase: extern "C" void abort() __attribute__ ((noreturn)); struct s { unsigned long long f1 : 40; unsigned int f2 : 24; } sv; int main() { int f2; sv.f2 = (1 << 24) - 1; __asm__ volatile ("" : : : "memory"); ++sv.f2; f2 = sv.f2; if (f2 != 0) abort(); return 0; } it doesn't fail with the C frontend though, even though the IL before expansion is the same: <unnamed-unsigned:24> D.1548; <bb 2>: sv.f2 = 16777215; __asm__ __volatile__("":::"memory"); D.1548 = sv.f2 + 1; sv.f2 = D.1548; if (D.1548 != 0) the difference is: (insn 13 10 14 3 t5.i:14 (set (reg/f:DI 67) - (const:DI (plus:DI (symbol_ref:DI ("sv") <var_decl 0x2b6b88bba320 sv>) + (const:DI (plus:DI (symbol_ref:DI ("sv") [flags 0x2] <var_decl 0x2b2e527ee0a0 sv>) (const_int 4 [0x4])))) -1 (nil)) (insn 14 13 15 3 t5.i:14 (set (reg:SI 69) @@ -197,59 +185,52 @@ (const_int 8 [0x8])) (nil))) -(insn 16 15 17 3 t5.i:14 (parallel [ - (set (reg:SI 58 [ D.1548 ]) +(insn 16 15 18 3 t5.i:14 (parallel [ + (set (reg:SI 58 [ D.2025 ]) (plus:SI (reg:SI 68) (const_int 1 [0x1]))) (clobber (reg:CC 17 flags)) ]) -1 (nil)) -(insn 17 16 19 3 t5.i:14 (parallel [ - (set (reg:SI 58 [ D.1548 ]) - (and:SI (reg:SI 58 [ D.1548 ]) - (const_int 16777215 [0xffffff]))) - (clobber (reg:CC 17 flags)) - ]) -1 (nil)) - -(insn 19 17 20 3 t5.i:14 (set (reg/f:DI 71) - (const:DI (plus:DI (symbol_ref:DI ("sv") <var_decl 0x2b6b88bba320 sv>) +(insn 18 16 19 3 t5.i:14 (set (reg/f:DI 71) + (const:DI (plus:DI (symbol_ref:DI ("sv") [flags 0x2] <var_decl 0x2b2e527ee0a0 sv>) (const_int 4 [0x4])))) -1 (nil)) -(insn 20 19 21 3 t5.i:14 (parallel [ +(insn 19 18 20 3 t5.i:14 (parallel [ (set (reg:SI 72) - (ashift:SI (reg:SI 58 [ D.1548 ]) + (ashift:SI (reg:SI 58 [ D.2025 ]) (const_int 8 [0x8]))) (clobber (reg:CC 17 flags)) ]) -1 (nil)) ... -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33887
next prev parent reply other threads:[~2007-12-11 12:50 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2007-10-24 23:44 [Bug c++/33887] New: " ian at airs dot com 2007-10-24 23:51 ` [Bug c++/33887] " pinskia at gcc dot gnu dot org 2007-10-25 5:07 ` ian at airs dot com 2007-10-25 5:22 ` pinskia at gcc dot gnu dot org 2007-10-25 13:25 ` ian at airs dot com 2007-12-08 20:07 ` [Bug middle-end/33887] [4.2/4.3 Regression] " pinskia at gcc dot gnu dot org 2007-12-11 12:38 ` rguenth at gcc dot gnu dot org 2007-12-11 12:50 ` rguenth at gcc dot gnu dot org [this message] 2007-12-11 13:08 ` [Bug c++/33887] " rguenth at gcc dot gnu dot org 2007-12-11 13:32 ` [Bug c++/33887] [4.1/4.2/4.3 " rguenth at gcc dot gnu dot org 2007-12-11 13:35 ` rguenth at gcc dot gnu dot org 2007-12-11 15:55 ` rguenth at gcc dot gnu dot org 2007-12-11 23:57 ` janis at gcc dot gnu dot org 2007-12-12 20:53 ` mmitchel at gcc dot gnu dot org 2007-12-12 22:04 ` janis at gcc dot gnu dot org 2007-12-12 22:47 ` rguenth at gcc dot gnu dot org 2007-12-14 14:32 ` bonzini at gnu dot org 2007-12-14 14:36 ` rguenther at suse dot de 2008-01-02 15:34 ` rguenth at gcc dot gnu dot org 2008-01-11 7:29 ` aoliva at gcc dot gnu dot org 2008-01-14 16:55 ` rguenth at gcc dot gnu dot org 2008-01-14 19:10 ` rguenth at gcc dot gnu dot org 2008-01-14 19:19 ` rguenth at gcc dot gnu dot org 2008-01-14 21:35 ` aoliva at gcc dot gnu dot org 2008-01-15 10:11 ` rguenth at gcc dot gnu dot org 2008-01-15 14:12 ` rguenth at gcc dot gnu dot org 2008-01-15 14:55 ` rguenth at gcc dot gnu dot org 2008-01-18 18:45 ` aoliva at gcc dot gnu dot org 2008-01-18 19:22 ` aoliva at gcc dot gnu dot org 2008-01-18 19:46 ` aoliva at gcc dot gnu dot org 2008-01-18 22:21 ` rguenth at gcc dot gnu dot org 2008-01-19 1:05 ` aoliva at gcc dot gnu dot org 2008-01-21 9:35 ` rguenth at gcc dot gnu dot org 2008-01-21 9:44 ` rguenth at gcc dot gnu dot org 2008-01-23 15:04 ` rguenth at gcc dot gnu dot org 2008-01-25 7:51 ` mmitchel at gcc dot gnu dot org 2008-01-25 12:15 ` rguenth at gcc dot gnu dot org 2008-01-25 12:56 ` [Bug c++/33887] [4.1/4.2 " rguenth at gcc dot gnu dot org 2008-01-25 20:57 ` tromey at gcc dot gnu dot org 2008-01-25 21:41 ` rguenth at gcc dot gnu dot org 2008-02-01 17:02 ` jsm28 at gcc dot gnu dot org 2008-02-07 18:04 ` rguenth at gcc dot gnu dot org 2008-03-12 14:27 ` rguenth at gcc dot gnu dot org 2008-03-12 14:31 ` rguenth at gcc dot gnu dot org 2008-04-18 14:04 ` aldot at gcc dot gnu dot org 2008-04-18 15:07 ` rguenth at gcc dot gnu dot org 2008-05-07 19:44 ` rguenth at gcc dot gnu dot org 2008-05-19 20:31 ` jsm28 at gcc dot gnu dot org 2008-07-04 22:53 ` [Bug c++/33887] [4.2 " jsm28 at gcc dot gnu dot org 2009-03-31 0:36 ` jsm28 at gcc dot gnu dot org
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