Comment # 6 on bug 55256 from Török Edwin

Created attachment 67624 [details]
bug.shader_test

A small piglit .shader_test that reproduces the bug:
$ bin/shader_runner -auto bug.shader_test
Probe at (0,0)
  Expected: 0.500000 0.500000 0.500000 1.000000
  Observed: 0.501961 1.000000 1.000000 1.000000
PIGLIT: {'result': 'fail' }

$ R600_LLVM=0 bin/shader_runner -auto bug.shader_test
PIGLIT: {'result': 'pass' }
$ LIBGL_ALWAYS_SOFTWARE=1 bin/shader_runner -auto bug.shader_test
PIGLIT: {'result': 'pass' }