http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48616
Summary: -ftree-vectorize -mxop miscompiles right shift Product: gcc Version: 4.6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassig...@gcc.gnu.org ReportedBy: kr...@kde.org Created attachment 23991 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23991 reduced testcase I just tested GCC 4.6 with -mxop and found that my testShift unit test is miscompiled. I tried hard to reduce the testcase further than what I got now, but it is very fragile, i.e. it produces correct code if I remove unrelated code, such as test calls after the problematic test. Compile the testcase with % g++ -mxop -O2 -ftree-vectorize testcase.cpp to get the error. Let me know if I can help further.