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From: "jakub at gcc dot gnu.org" <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 12:59:00 -0000 [thread overview] Message-ID: <bug-46716-4-5vel58AMqd@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 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |NEW CC| |hjl at gcc dot gnu.org, | |hubicka at gcc dot gnu.org AssignedTo|jakub at gcc dot gnu.org |unassigned at gcc dot | |gnu.org --- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-30 12:35:56 UTC --- Well, apparently -mno-sse2 doesn't disable completely SSE2 use, vectors are still passed in %xmm* registers for -m64. See i386.c (type_natural_mode). The problem is that then we have a parameter, where data->nominal_mode (and passed_mode and promoted_mode) is BLKmode, but data->entry_parm is (reg:V2DF 21 xmm0 [ s1 ]). assign_parm_setup_block_p because of the BLKmode nominal_mode returns true and assign_parm_setup_block copies it in wordsize (DImode here) parts, incrementing REGNO for each part. So, we end up passing first half of first parameter in %xmm0, second half in %xmm1, first half of second parameter in %xmm1 and second half of second parameter in %xmm2 (both on the caller and callee side). I guess generic vector support in 3.4 was even more broken and it just didn't care and used V2DFmode for the type even with -mno-sse2. And of course using -mno-sse2 in x86-64 on code that uses vectors makes no sense at all. Anyway, not sure how to convince the middle-end to handle this "right" for whatever definition of right, without risking breaking other targets too much.
next prev parent reply other threads:[~2010-11-30 12:36 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 [this message] 2010-11-30 13:49 ` hjl.tools at gmail dot com 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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