I don't know the right terminology to describe it. Often it's black (or background-colored) regions. Sometimes things get fixed when I mouse over the areas or resize the window. It seems to happen independently of whether I have SSE enabled, and whether or not I add ASAN into the mix. I need to debug further...
This issue appears at default optimization and at -O1, but not in --disable-optimize builds.
I can see this with --disable-optimize (--enable-debug) builds, but not in --enable-optimize builds (--enable-optimize builds hit an assert that we don't see in regular MSVC builds, and the process exits).
It's been several months, does this bug still reproduce?
This bug does not reproduce for me with recent clang-cl. I'm going to call it good.