Constraining Relative Skew in TimeQuest? Help!

Hello Daixiwen,

Our Altera FAE mentioned something along those lines, but later said that solution could only be applied to I/O, not internal signals.

When pressed he said I'll have to wait until next year when a future version of TimeQuest / Quartus will directly support skew constraints (and wait even longer for these constraints to drive place & route).

I don't get it. How in the hell are Altera async FIFOs working now? Relying on the multicycle default of setup=1 and hold=0 would almost certainly either overconstrain or underconstrain them (because multicycle is based on both the LAUNCH clock and the LATCH clock). Underconstraining is really dangerous here, and overconstraining might prevent timing closure.