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From: "hjl.tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/46716] [4.3/4.4/4.5/4.6 Regression] bad code generated with -mno-sse2 -m64 Date: Tue, 30 Nov 2010 13:49:00 -0000 [thread overview] Message-ID: <bug-46716-4-K2M5VQQhJo@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-46716-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46716 H.J. Lu <hjl.tools at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC|hjl at gcc dot gnu.org |hjl.tools at gmail dot com, | |ubizjak at gmail dot com --- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> 2010-11-30 13:40:23 UTC --- From http://gcc.gnu.org/ml/gcc/2010-11/msg00650.html I think this is a compiler bug in the i386 backend. The classify_argument function uses X86_64_SSEUP_CLASS for V2DFmode, and examine_argument counts that as requiring a single SSE register. However, since the SSE2 instructions are not available, the argument is split into two SSE registers. The result is that the first argument is passed in %xmm0/%xmm1, and the second argument is passed in %xmm1/%xmm2. That is, the arguments overlap, leading to the incorrect result. Basically, the 64-bit calling convention support assumes that the SSE2 instructions are always available, and silently fails when -mno-sse2 is used. I don't really have an opinion as to whether the compiler needs to support this case correctly, but I think that clearly it must not silently fail.
next prev parent reply other threads:[~2010-11-30 13:40 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-11-30 0:59 [Bug c/46716] New: " mathog at caltech dot edu 2010-11-30 10:01 ` [Bug target/46716] [4.3/4.4/4.5/4.6 Regression] " jakub at gcc dot gnu.org 2010-11-30 12:36 ` rguenth at gcc dot gnu.org 2010-11-30 12:59 ` jakub at gcc dot gnu.org 2010-11-30 13:49 ` hjl.tools at gmail dot com [this message] 2010-11-30 17:50 ` mathog at caltech dot edu 2010-12-05 12:03 ` rguenth at gcc dot gnu.org 2011-01-03 20:28 ` rguenth at gcc dot gnu.org 2011-06-27 13:40 ` [Bug target/46716] [4.3/4.4/4.5/4.6/4.7 Regression] wrong " rguenth at gcc dot gnu.org 2012-03-02 14:36 ` [Bug target/46716] [4.4/4.5/4.6/4.7 " ubizjak at gmail dot com 2012-03-02 17:04 ` [Bug target/46716] [4.4/4.5/4.6/4.7/4.8 " uros at gcc dot gnu.org 2012-03-13 14:08 ` [Bug target/46716] [4.5/4.6/4.7/4.8 " jakub at gcc dot gnu.org 2012-07-02 12:10 ` rguenth at gcc dot gnu.org 2013-04-12 15:16 ` [Bug target/46716] [4.7/4.8/4.9 " jakub at gcc dot gnu.org 2014-01-23 7:12 ` law at redhat dot com
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