[Intel-gfx] [PATCH 2/2] drm/i915: Ensure intel_engine_init_execlist() builds with Clang

[Stephen Boyd]

Quoting Jani Nikula (2018-10-16 05:29:38)
> Clang build with UBSAN enabled leads to the following build error:
> 
> drivers/gpu/drm/i915/intel_engine_cs.o: In function `intel_engine_init_execlist':
> drivers/gpu/drm/i915/intel_engine_cs.c:411: undefined reference to `__compiletime_assert_411'
> 
> Again, for this to work the code would first need to be inlined and then
> constant folded, which doesn't work for Clang because semantic analysis
> happens before optimization/inlining.
> 
> Use GEM_BUG_ON() instead of BUILD_BUG_ON().
> 
> v2: Use is_power_of_2() from log2.h (Chris)
> 
> References: http://mid.mail-archive.com/20181015203410.155997-1-swboyd@chromium.org
> Reported-by: Stephen Boyd <swboyd at chromium.org>

Tested-by: Stephen Boyd <swboyd at chromium.org>