SPIR-V Built-In
NumSubgroups
Number of subgroups in a workgroup
NumSubgroups
Decorating a variable with the NumSubgroups built-in decoration will
make that variable contain the number of subgroups in the local workgroup.
Valid Usage
VUID-NumSubgroups-NumSubgroups-04293
The NumSubgroups decoration must be used only within the
GLCompute, MeshEXT, TaskEXT, MeshNV, or TaskNV
Execution Model
VUID-NumSubgroups-NumSubgroups-04294
The variable decorated with NumSubgroups must be declared using
the Input Storage Class
VUID-NumSubgroups-NumSubgroups-04295
The variable decorated with NumSubgroups must be declared as a
scalar 32-bit integer value