https://bugs.freedesktop.org/show_bug.cgi?id=89069
--- Comment #6 from smoki smoki00790@gmail.com ---
Thanks for confirmation.
I know those float point math optimization behave like this, if someone build llvm with gcc and with '-Ofast' that is '-O3 -ffast-math' there are visual regressions (missing fog, etc), but piglits also shows that regression.
Weird thing about this is that piglit does not show any regression :( but well as we confirm visually grass is not there... Lately '-no-nans-fp-math' is also enabled, so i am a little bit suspicious that it might show similar issue somewhere too.