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From: "hjl dot tools at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/45365] New: X86 FP add and multiply aren't commutative Date: Sat, 21 Aug 2010 03:42:00 -0000 [thread overview] Message-ID: <bug-45365-682@http.gcc.gnu.org/bugzilla/> (raw) According to table 4-7 in chapter 4, Vol 1 of IA32/Inte64 SDM, x86 FP add and multiply aren't commutative with Qnan/Snan inputs. But we have DEF_RTL_EXPR(PLUS, "plus", "ee", RTX_COMM_ARITH) DEF_RTL_EXPR(MULT, "mult", "ee", RTX_COMM_ARITH) That impacts x86 FP plus and mult patterns. Should we introduce a new target option to disable x86 commutative FP plus and mult? -- Summary: X86 FP add and multiply aren't commutative Product: gcc Version: 4.5.3 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: hjl dot tools at gmail dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45365
next reply other threads:[~2010-08-21 3:42 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-08-21 3:42 hjl dot tools at gmail dot com [this message] 2010-08-21 3:54 ` [Bug target/45365] " hjl dot tools at gmail dot com 2010-08-21 3:59 ` pinskia at gcc dot gnu dot org 2010-08-21 4:10 ` hjl dot tools at gmail dot com 2010-08-21 4:15 ` hjl dot tools at gmail dot com 2010-08-23 16:30 ` [Bug target/45365] X86 SSE FP add and multiply aren't commutative with 2 NaNs hjl dot tools at gmail dot com
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