P1774 Portable assumptions

[wg21bot]

P1774R0 Portable optimisation hints (Timur Doumler)

[wg21bot]

P1774R1 Portable optimisation hints (Timur Doumler)

[jfbastien]

Let's do EWGI first.

[theres-waldo]

EWG-I in Belfast

P1774 with [[assume(expr)]] syntax:

SF	F	N	A	SA	num. attendees
15	5	1	0	0	22

P1774 with std::assume(expr) syntax:

SF	F	N	A	SA	num. attendees
1	3	4	10	4	22

[wg21bot]

P1774R2 Portable assumptions (Timur Doumler)