[DAG] Fold nested add(add(reduce(a), b), add(reduce(c), d)) (#115150)

This patch reassociates `add(add(vecreduce(a), b), add(vecreduce(c),
d))` into `add(vecreduce(add(a, c)), add(b, d))`, to combine the
reductions into a single node. This comes up after unrolling vectorized
loops.

There is another small change to move reassociateReduction inside fadd
outside of a AllowNewConst block, as new constants will not be created
and it should be OK to perform the combine later after legalization.

0 files changed, 0 insertions, 0 deletions