6ca81adffc
If the condition of the loop terminator is based on an unsigned value we
can in some cases find the max number of possible loop trips. With the
max loop trips know a complex unroll can unroll the loop.
For example:
uniform uint x;
uint i = x;
while (true) {
if (i >= 4)
break;
i += 6;
}
The above loop can be unrolled even though we don't know the initial
value of the induction variable because it can have at most 1 iteration.
There were no changes with my shader-db collection. Change was inspired
by MR #31312 where builtin shader code failed to unroll.
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31701>