This pass tries to move register usage closer to SSA, and for large
shaders this means we can overflow the register index, which only has
RC_REGISTER_INDEX_BITS size. This creates invalid code and leads to
crash at a later stage. Limit the pool of available registers to
RC_REGISTER_MAX_INDEX, currently is was two times the number of
shader instructions.
This means we'll fail the compile right away if we wanted more than
RC_REGISTER_MAX_INDEX temps, but when we've got that many we're
already well past how many instructions we can support anyway.
CC: mesa-stable
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/6017
Signed-off-by: Pavel Ondračka <pavel.ondracka@gmail.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17393>
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