This revision adds DeviceMaskingAttrInterface and extends
DeviceMappingArrayAttr to accept a union of DeviceMappingAttrInterface
and DeviceMaskingAttrInterface.
Support is added to GPUTransformOps to take advantage of this
information and lower to block/warpgroup/warp/thread specialization when
mapped to linear ids.
The revision also connects to scf::ForallOp and uses the new attribute
to implement warp specialization.
The implementation is in the form of a GPUMappingMaskAttr, which can be
additionally passed to the scf.forall.mapping attribute to specify a
mask on compute resources that should be active.
In the first implementation the masking is a bitfield that specifies for
each processing unit whether it is active or not.
In the future, we may want to implement this as a symbol to refer to
dynamically defined values.
Extending op semantics with an operand is deemed too intrusive at this
time.
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Co-authored-by: Oleksandr "Alex" Zinenko <git@ozinenko.com>
2b28d10022