As initially reported here http://bugs.gentoo.org/show_bug.cgi?id=276146 I'm interested whether this issue is fixed or whether it doesn't appear in within recent version of gcc.
-- Summary: wrongly optimize "area+= x0*y1 - x1*y0;" Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: other AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: toralf dot foerster at gmx dot de GCC build triplet: gcc-4.3.2-r3 GCC host triplet: x86 GCC target triplet: Gentoo Linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41641