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

[Alastair_D_1]

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:

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System Setup Information:
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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:
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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:
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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:
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The shaders render completely different images, which they should not.

Additional Information:
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N/A

[Michael_C_Intel2]

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

[Alastair_D_1]

Hi Michael

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

Cheers

Ally

[Michael_C_Intel2]

Awesome! Glad to hear. 

-Michael