> It's really irritating, as someone who works in C and C++ with good reason, to hear people continually deny the very real performance benefits of working at a lower level.
As someone who also works at a very low level, I also know the limits of precompiled optimizations!
In perfect theory land, a Sufficiently Smart JITTER will beat out a Sufficiently Smart Compiler, if for no other reason than the JITTER can always take advantage per CPU optimizations for CPUs newer than whenever precompiled code was compiled for! e.g. in theory code written ages ago gets free performance boosts.
JITTERs also have the benefit of knowing the state at run time. Doing things like only compiling code that is actually being used right now means in theory fitting more stuff throughout all layers of the memory subsystem, and we all know how important cache hit rates are to performance!
JITTERs also have access to the entire bytecode of a program, which lets it do even stranger optimizations if it so decides (again, sufficiently smart), where as a compiler cannot do much about libraries you link to dynamically (or even statically, doing optimizations on pure assembly is Not Fun)
Of course some compiler tools, such as Link Time Code Generation (also called Whole Program Optimization), and Profile Guided Optimizations can get you close to what a JITTER has by feeding the compiler a ton of additional data at compile time, but again all you have done is tried to give the compiler an approximation of what a JITTER already has available to it.
Now one thing C++ most certainly wins out on is that it is possible to create very thin lightweight wrappers around functionality, which will have huge perf gains in comparison to the multilevel abstractions that software engineers (myself included!) tend to enjoy creating when they get a hold of a VM based language (be it JVM, CLR, or pick your favorite bytecode).