Adding expression after "return" statement causes wrong image to be rendered

Alastair_D_1 — Wed, 23 Nov 2016 20:37:25 GMT

The files associated with the bug are here:

https://github.com/mc-imperial/shader-compiler-bugs/tree/master/Intel-HD-Graphics-520-Windows/wrong_images/large-v440-1f1265b42fca6aab_inv_variant_37

System Setup Information:

-----------------------------------------

System Setup Information:
-----------------------------------------

System Used: Dell XPS
CPU SKU: i7
GPU SKU: HD 520
Processor Line: U-Series
System BIOS Version: Dell Inc. 1.0.0, 10/09/2015
CMOS settings: I can check on request
Graphics Driver Version: 20.19.15.4501
GOP/VBIOS Version: Intel Video BIOS
Operating System: Windows 10
OS Version: Pro
API: OpenGL
Occurs on non-Intel GPUs?: Haven't tried

Steps to Reproduce:
-------------------------------

1. Obtain the latest release of get-image, a simple tool that creates
a .png image from a fragment shader (alternatively, use some other
method observing the effect of a fragment shader)

2. From a command prompt, execute:

C:\path\to\get_image\bin\Windows\get_image.exe original.frag

This will create output.png, which should look like original.png

3. From a command prompt, execute:

C:\path\to\get_image\bin\Windows\get_image.exe variant.frag

This will create output.png, which should look like variant.png

Expected Results:
-------------------------------
Both shaders should render an image that looks like original.png. This is because the only difference between the .frag files is:

- There is an expression, 1.0, right after the return statement in
"color_at". This expression is unreachable and side-effect free, so
should not impact on the results of shader execution.

Actual Results:
-------------------------------
The shaders render completely different images, which they should not.

Additional Information:
-------------------------------
N/A

Hi Alastair,

Michael_C_Intel2 — Tue, 29 Nov 2016 18:33:13 GMT

Hi Alastair,

Can you see if the issue reproduces on this new driver?

https://downloadcenter.intel.com/download/26404/Intel-Graphics-Driver-15-45-

-Michael

Hi Michael

Alastair_D_1 — Mon, 05 Dec 2016 20:54:40 GMT

Hi Michael

This one seems to be fixed with the new driver - great.

Cheers

Ally

Awesome! Glad to hear.

Michael_C_Intel2 — Tue, 06 Dec 2016 22:56:32 GMT

Awesome! Glad to hear.

-Michael

topic Adding expression after "return" statement causes wrong image to be rendered in Graphics

Adding expression after "return" statement causes wrong image to be rendered

Hi Alastair,

Hi Michael

Awesome! Glad to hear.