tree 532befe9c01b65258842be398f26789567478e4d
parent 458f703ec39a873dc46ba3041f71eb387e6a161d
author Antonio Maiorano <amaiorano@google.com> 1709082062 +0000
committer Dawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1709082062 +0000

tint: work around zero-init bug on some GPUs for workgroup size(1)

This was seen specifically on Windows with an AMD GPU, when using DXC to
compile compute shaders with workgroup size of 1. Flaky, but
reproducible when running CTS test:
webgpu:shader,execution,zero_init:compute,zero_init:addressSpace="workgroup";workgroupSize=[1,1,1];*

We are generating valid code in Tint, but this workaround makes it so
that DXC opts to emit the zero-init instructions rather than tagging the
groupshared variable as 'zeroinitializer'. This seems to make the buggy
driver happy.

Also see: https://github.com/microsoft/DirectXShaderCompiler/issues/6352

Bug: tint:2143
Change-Id: If84b992c4961bafeb1a8ff328626d3f6cf1fb98d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/176140
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>