> No, GCC hit a fundamental wall because its backend was not modern. > The code we generate out of tree-ssa is in general, as good or better > than other compilers generate out of their middle ends. > > The problem remaining is that they have much better backends then us. > > Until dataflow, *nobody* had done any sort of major undertaking to > make the *entire* backend actually modern in any way, shape or form.
I presume that "backend" means the RTL part of the compiler, right? So we should focus our efforts on the low-level part of the compiler, rather than on the high-level part? E.g the register allocator? > Our backends have done roughly the same good/bad job of generating > code since, well, forever. Until that changes, you will see that the > only performance improvements you get in the general case are things > that the backend was too dumb to get in the first place (IE loads, > stores) Note that Tree-SSA was supposed to butcher the RTL optimizers and replace them with something less "crappy" though. -- Eric Botcazou
