[RISCV] Use APInt in isSimpleVIDSequence to account for index overflow (#100072)

At zvl1024b, we may have legal fixed length vectors where a vid.v would
overflow at i8, e.g. <512 x i8>.

When lowering constant build_vectors, isSimpleVIDSequence used uint64_t
to model the vid.v sequence which meant it didn't account for the fact
that it could overflow in these larger types.

This patch fixes it by modelling the sequence with an SEW-wide APInt so
if it does overflow the loop that checks/calculates the addend will
detect it and bail.

Fixes #99729

0 files changed, 0 insertions, 0 deletions