When the enclosed test case is compiled with -O3, the vectorization code loads and SSE register with 0x00000001000000010000000100000001 instead of 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF, then ANDs this with elements of the array. This causes the code to fail.
-- Summary: vectorization ANDs array elements together incorrectly Product: gcc Version: unknown Status: UNCONFIRMED Severity: major Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: Daniel dot Davies at xerox dot com GCC build triplet: i386-pc-solaris2.10 GCC host triplet: i386-pc-solaris2.10 GCC target triplet: i386-pc-solaris2.10 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44507