Bug 84758

Summary: Register spilling with gl_VertexID
Product: Mesa Reporter: Eero Tamminen <eero.t.tamminen>
Component: Drivers/DRI/i965Assignee: Ian Romanick <idr>
Status: RESOLVED DUPLICATE QA Contact: Intel 3D Bugs Mailing List <intel-3d-bugs>
Severity: normal    
Priority: medium CC: jason, petri.latvala
Version: git   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:
Bug Depends on:    
Bug Blocks: 77547    

Description Eero Tamminen 2014-10-07 15:27:56 UTC 
HS/SW setup:
- HSW GT3e
- Mesa git from 2014-09-30
- Ubuntu 14.04

Test-case:
- Build ogl-samples test-suite from:
  https://github.com/g-truc/ogl-samples.git
- Run following test:
  build/Release/gl-400-fbo-rtt-texture-array

Actual result:
- "Vertex shader triggered register spilling.  Try reducing number of live vec4 value to improve performance."

Expected result:
- No register spilling with this simple vertex shader


Vertex shader is this:
https://github.com/g-truc/ogl-samples/blob/master/data/gl-400/rtt-array.vert

Code for the test is here:
https://github.com/g-truc/ogl-samples/blob/master/tests/gl-400-fbo-rtt-texture-array.cpp


Same thing happens also with the other tests using gl_VertexID as array index to small const array, for example with gl-320-draw-without-vertex-attrib test:
https://github.com/g-truc/ogl-samples/blob/master/data/gl-320/draw-without-vertex-attrib.vert

(which doesn't require setting these like gl-400-fbo-rtt* tests do:
  MESA_GL_VERSION_OVERRIDE=4.00
  MESA_GLSL_VERSION_OVERRIDE=400
)
Comment 1 Kenneth Graunke 2014-10-09 13:56:01 UTC 

*** This bug has been marked as a duplicate of bug 77957 ***

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