Date: Thu, 6 Sep 2012 11:20:24 +0100 From: David Chisnall <theraven@FreeBSD.org> To: Roman Divacky <rdivacky@FreeBSD.org> Cc: Garrett Cooper <yanegomi@gmail.com>, Dimitry Andric <dimitry@andric.com>, freebsd-current@FreeBSD.org, Steve Kargl <sgk@troutmask.apl.washington.edu> Subject: Re: Compiler performance tests on FreeBSD 10.0-CURRENT Message-ID: <122361C5-7B83-494B-A580-970FAFF83CAA@FreeBSD.org> In-Reply-To: <20120906084312.GA13223@freebsd.org> References: <5046670C.6050500@andric.com> <20120904214344.GA17723@troutmask.apl.washington.edu> <504679CB.90204@andric.com> <20120904221413.GA19395@troutmask.apl.washington.edu> <CAGH67wTQavfh9ExsjypnCjw4yrV2RpdUUjxAD2kaZy-PiDocHA@mail.gmail.com> <50471BEE.6030708@andric.com> <20120905221310.GA97847@troutmask.apl.washington.edu> <20120906084312.GA13223@freebsd.org>
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On 6 Sep 2012, at 09:43, Roman Divacky wrote: > Was this compiled as amd64 or i386? Also, can you send me the test case? > So that we can explore the difference. The working theory now is SSE vs FPU > mathematics, but it would be nice to see the testcase. There may also be a difference in whether -ffast-math is the default on each compiler. On x86, this will replace a number of libm calls with (much faster, but less accurate) SSE or x87 instructions. If this is enabled by default with clang and not with gcc, it would account for the difference. Davidhelp
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