I dont think this is NOT true. Two reasons why. The first is register allocation algorithms have gotten really good at breaking up lifetimes of registers and pr

I dont think this is NOT true. Two reasons why. The first is register allocation algorithms have gotten really good at breaking up lifetimes of registers and producing near optimal spillcode. And the second reason is that most of the time the penalty you take is L1_ACCESS_TIME - REG_ACCESS_TIME + pushtime + poptime. On modern OOO machine with modern day L1 caches with optimized HW prefetching this is almost 0. Seriously. -edit: left out not :)