Shader rendered with darker background and blue patch on addition of unreachable returns

[afd]

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

Recipient:

Variant 1:

Variant 2:

WebGL viewer for recipient:

http://htmlpreview.github.io/?https://github.com/mc-imperial/shader-compiler-bugs/blob/master/NVIDIA-770-WebGL-ANGLE/wrong_images/slug/webgl_viewer_recipient.html

WebGL viewer for variant 1, which has two unreachable return statements:

http://htmlpreview.github.io/?https://github.com/mc-imperial/shader-compiler-bugs/blob/master/NVIDIA-770-WebGL-ANGLE/wrong_images/slug/webgl_viewer_variant1.html

This cause a darker background and a blue patch to appear.

WebGL viewer for variant 2, which has just one unreachable return statement:

http://htmlpreview.github.io/?https://github.com/mc-imperial/shader-compiler-bugs/blob/master/NVIDIA-770-WebGL-ANGLE/wrong_images/slug/webgl_viewer_variant2.html

The background is still darker, but there is no blue patch.

Platform details:

• Windows 10
• Google Chrome Version 57.0.2987.110 (64-bit)
• NVIDIA GeForce GTX 770
• Driver version 21.21.13.7878

This does not appear to be an ANGLE bug as it does not repro on an Intel GPU on a Windows platform with the same Chrome version.

[0152la]

Did not observe differences between the recipient and two variants on:

• Firefox on Archlinux running Mesa 13.0.3 on an Intel i7
• Firefox on Ubuntu 16.04.2 running Mesa 17.0.1 on an AMD R9
• Chrome and Edge on Windows 10 running Radeon 17.2.1 on an AMD R9 Fury
• Firefox on Ubuntu 16.10 running Nvidia proprietary drivers 375.39 on a GTX980M

[afd]

We haven't yet reported this one.