Date: Wed, 05 Apr 2017 01:35:39 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 218387] -march=native or any specific CPU seems to produce x87 math a lot Message-ID: <bug-218387-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=218387 Bug ID: 218387 Summary: -march=native or any specific CPU seems to produce x87 math a lot Product: Base System Version: CURRENT Hardware: amd64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: bin Assignee: freebsd-bugs@FreeBSD.org Reporter: kungfujesus06@gmail.com I think this is a bug, but perhaps I just think it is because the behavior diverges from GCC by quite a bit. When you compile an application that does floating point math with clang in current right now, specifying -march=native or -march=sandybridge or btver2 or any number of CPUs I tried to target produces predominantly x87 instructions. Typically GCC and most other compilers I've seen default to targeting SSE instructions, instead. If you specify -march=x86-64, you get the results you'd expect (predominantly SSE2 instructions for floating point). This leads me to believe this is a bug, for most everything SSE units should be the most optimal. -- You are receiving this mail because: You are the assignee for the bug.
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