To query the core count, the hardware has a SHADERS_PRESENT register containing
a mask of shader cores connected. The core count equals the number of 1-bits,
regardless of placement. This value is useful for public consumption (like
in clinfo).
However, internally we are interested in the range of core IDs.
We usually query core count to determine how many cores to allocate various
per-core buffers for (performance counters, occlusion queries, and the stack).
In each case, the hardware writes at the index of its core ID, so we have to
allocate enough for entire range of core IDs. If the core mask is
discontiguous, this necessarily overallocates.
Rename the existing core_count to core_id_range, better reflecting its
definition and purpose, and repurpose core_count for the actual core count.
Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17265>
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