[taf2]

you're kidding right? and at least referring to gcc's -fprofile-generate -fprofile-use right?

[tptacek]

Profile-guided optimization is decades old. It was, for example, one of the things people loved about the (Ultrix?) DEC Alpha compiler was profile-driven optimization.

[wglb]

First VMS.

That was one of the outstanding compilers ever written.

[pbiggar]

There is a major difference between performing profile-generated optimizations at compile-time based on sample data, and performing it at run-time based on real data. It is one pretty good way in which JITs could beat programs implemented directly in C.

[gillianseed]

Not really since the 'sample' data is 'real' data which has been gathered during run-time.

[pbiggar]

That is the most optimistic statement about profile-directed optimization that I have ever read.