<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Incorrect code generation for atomic operations if HAVE_INTEL_ATOMIC_PRIMITIVES defined" href="https://bugs.freedesktop.org/show_bug.cgi?id=103559#c3">Comment # 3</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Incorrect code generation for atomic operations if HAVE_INTEL_ATOMIC_PRIMITIVES defined" href="https://bugs.freedesktop.org/show_bug.cgi?id=103559">bug 103559</a> from <a class="email" href="mailto:fludkov.me@gmail.com" title="Mikhail Fludkov <fludkov.me@gmail.com>"> Mikhail Fludkov</a> <pre>(In reply to Adrian Johnson from <a href="show_bug.cgi?id=103559#c2">comment #2</a>) > I would just use __sync_fetch_and_add(x, 0) for the get. The C++11 atomics > were added in gcc 4.7 (about 5 years ago). Anyone caring about speed should > be using a recent version of gcc. Agree it will be explicit and less "magical". What about using the same implementation regardless of ATOMIC_OP_NEEDS_MEMORY_BARRIER define? The naming is a bit confusing though. When I read HAVE_INTEL_ATOMIC_PRIMITIVES define, I immediately thought about Intel Compiler and the libraries that come with it. Maybe HAVE_GCC_41_ATOMICS, or HAVE_GCC_OLD_ATOMICS names are better? > What version of gcc were you using? Maybe the old versions that don't > support C++11 atomics do not optimize away the read. We backported the patch (<a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED FIXED - Segmentation fault in _cairo_traps_compositor_glyphs" href="show_bug.cgi?id=103037">https://bugs.freedesktop.org/show_bug.cgi?id=103037</a>) on top of libcairo version which didn't have the code under HAVE_CXX11_ATOMIC_PRIMITIVES define. Compiled with gcc 4.9, ended up with a hot loop.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>