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From: "suckfish at ihug dot co dot nz" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/37807] Exponential compile time with MMX builtins. Date: Sat, 11 Oct 2008 23:25:00 -0000 [thread overview] Message-ID: <20081011232415.30697.qmail@sourceware.org> (raw) In-Reply-To: <bug-37807-2018@http.gcc.gnu.org/bugzilla/> ------- Comment #6 from suckfish at ihug dot co dot nz 2008-10-11 23:24 ------- I think this function actually gets miscompiled: typedef int v2si __attribute__ ((vector_size (8))); v2si foo (v2si x) { x &= (v2si) 0xffffffffll; x = __builtin_ia32_psrad (x, 1); x &= (v2si) 0x80000000ll; return x; } to foo: pxor %xmm0, %xmm0 ret The psrad is preserving the sign bit we are returning, so the compiler should not assume it to be zero. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37807
next prev parent reply other threads:[~2008-10-11 23:25 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2008-10-11 21:22 [Bug c/37807] New: " suckfish at ihug dot co dot nz 2008-10-11 21:22 ` [Bug c/37807] " suckfish at ihug dot co dot nz 2008-10-11 21:36 ` suckfish at ihug dot co dot nz 2008-10-11 22:07 ` rguenth at gcc dot gnu dot org 2008-10-11 22:24 ` suckfish at ihug dot co dot nz 2008-10-11 23:03 ` suckfish at ihug dot co dot nz 2008-10-11 23:25 ` suckfish at ihug dot co dot nz [this message] 2008-10-12 2:40 ` suckfish at ihug dot co dot nz 2008-10-12 4:48 ` suckfish at ihug dot co dot nz 2008-10-12 5:23 ` suckfish at ihug dot co dot nz 2008-10-12 5:28 ` suckfish at ihug dot co dot nz 2008-10-12 10:31 ` [Bug middle-end/37807] " rguenth at gcc dot gnu dot org 2008-11-10 9:11 ` uros at gcc dot gnu dot org 2008-11-10 10:46 ` uros at gcc dot gnu dot org 2008-11-10 12:23 ` uros at gcc dot gnu dot org 2008-11-10 12:26 ` ubizjak at gmail dot com
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