Does a compiler use all x86 instructions? (2010)
My question is if compilers use "new" x86 instructions, as then the program won't work at all on old systems.For example, if Intel decided today that CPUs need a new "fast" hashing opcode (I don't know if they actually do),  a compiler can't compiles to it, as programs won't work on older computers.Is it like the API cruft in Android, where "new" Lollipop APIs are introduced for 10 years from now, when no one uses any phones from before 2014?