* Paolo Carlini: > Actually, the situation is not as bad, as far as I can see: the worst > case is i386 vs i486+, and Old-Sparc vs New-Sparc. More generally, a > targer either cannot implement the builtin at all (a trivial fall back > using locks or no MT support at all) or can in no more than 1 > non-trivial way.
Isn't IA32 a counter-example for this? Non-SMP or non-threaded (normal INC/DEC), SMP (LOCK INC/DEC), and modern SMP (something else) already results in three choices.
