Unreachable control flow causes shader not to render

[0152la]

[Shaders, screenshots, error log, reproduction steps, platform info, etc.] [ZIP]

Variant correct:

Variant:

![incorrect image](https://github.com/mc-imperial/shader-compiler-bugs/raw/master/AMD-R9-Fury-Windows10/wrong_images/large-v440-028011ce6441692b_inv_variant_63_2/variant_incorrect.png"incorrect image")

Both shaders write red to gl_FragColor, then have some further unreachable code. In the case of variant_incorrect.frag, we observe a green colour as output. The launcher we used initially sets the buffer colour to green. This indicates that the discard statement is actually executed.

We have also obtained the Fiji ISA (corresponding to the R9 Fury GPU) via the Radeon GPU Analyzer tool. We observe that lines 15 in the two files are performing opposite comparisons.

[0152la]

This issue is a further investigation of #7. It has also been reported to AMD via email, which have confirmed an issue exists.

[afd]

Driver version 17.6.2 on Windows 10 64, bit