Bug 189122 - [WHLSL] Enumerate which operations require uniform control flow and dynamically uniform expressions
Summary: [WHLSL] Enumerate which operations require uniform control flow and dynamical...
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: WebGPU (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks: 176199 189202
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Reported: 2018-08-29 16:35 PDT by Myles C. Maxfield
Modified: 2018-10-13 14:50 PDT (History)
2 users (show)

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Description Myles C. Maxfield 2018-08-29 16:35:44 PDT 
Indexing into an array of textures requires a dynamically uniform expression
sample() involves an implicit derivative, and so requires uniform control flow
Comment 1 Radar WebKit Bug Importer 2018-09-12 18:50:46 PDT 
<rdar://problem/44402999>
Comment 2 Myles C. Maxfield 2018-09-22 23:51:38 PDT 
The following functions require uniform control flow:

ddx()
ddy()
AllMemoryBarrierWithGroupSync()
DeviceMemoryBarrierWithGroupSync()
GroupMemoryBarrierWithGroupSync()
Sample()
SampleBias()
Gather()
GatherRed()
GatherGreen()
GatherBlue()
GatherAlpha()
SampleCmp()
GatherCmp()
GatherCmpRed()
GatherCmp()
GatherCmpRed()
Comment 3 Myles C. Maxfield 2018-09-22 23:52:57 PDT 
Indexing into an array which contains textures requires dynamically uniform expressions. I think that's the only operation.
Comment 4 Myles C. Maxfield 2018-09-22 23:54:08 PDT 
I suppose this is done now.
Comment 5 Myles C. Maxfield 2018-10-13 14:50:33 PDT 
Migrated to https://github.com/gpuweb/WHLSL/issues/58