[john-h-k]

Very few compilers actually use vertex coloring for register allocation

[isaacimagine]

Totally. The hard part isn't coloring (you can use simple heuristics to get a decent register assignment), rather, it's figuring out which registers to spill (don't spill registers in hot loops! and a million other things!).

[NooneAtAll3]

and this post isn't even about vertex coloring