Among others, it would result in the spill offsets being wrong due to
being relative to the parent split and not absolute.
For example when computing a 64-bit multiply on Tesla (which only
supports 16-bit mul in hardware), the sources will first be split into
32-bit values and then a second time down to 16-bit ones. Looking at the
first source, the spill offsets ended being computed as follows:
{ .hihi = +2, .hilo = +0, .lohi = +2, .lolo = +0 }
instead of the expected
{ .hihi = +6, .hilo = +4, .lohi = +2, .lolo = +0 }
This is resolved with this patch.
Signed-off-by: Pierre Moreau <dev@pmoreau.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10711>
