Below is an excerpt from the IRS Instructions (emphasis and bullets added).
Form 8949 isn't required for
You may be able to
aggregate those transactions
report them directly on either
line 1a (for short-term transactions) or
line 8a (for long-term transactions) of
This option applies only to transactions
(other than sales of collectibles) for which:
You received a Form 1099-B (or substitute statement) that shows basis was reported to the IRS
doesn't show any adjustments in box 1f or 1g;
The Ordinary box in box 2 isn’t checked;
You don't need to make any adjustments to the basis or type of gain or (loss)
reported on Form 1099-B (or substitute statement), or to your gain or (loss); and
You aren't electing to defer income due to an investment in a QOF and
aren't terminating deferral from an investment in a QOF.
If you choose to report these transactions
directly on Schedule D,
you don't need to include
them on Form 8949 and don't need to attach a statement.
For more information, see the Schedule D instructions.
If you qualify to use Exception 1 and
also qualify to use Exception 2, you can use both.
Report the transactions that qualify for
Exception 1 directly on either line 1a or
8a of Schedule D, whichever
Report the rest of your transactions
as explained in