On 22/11/2017 13:14, Peter Maydell wrote: >> We do this all of the time for more regular tests that are obviously >> compile-time. I am a really big fan of this, because it makes sure that the >> (usually 32-bit) else branch continues to compile. > I'm happy with code that is "we assume the compiler is going to > be sensible here so we don't have to use #ifdefs in the name > of performance". I just don't think we should write code that > can't compile at all if the compiler happens to not identify > the codepath as dead. There's no guarantee by the compiler > that it's going to do that.
There's plenty of cases where "if (kvm_enabled())" code would fail to link if the compiler didn't do that optimization. (In fact, it's one of the very few optimizations that the compiler performs at -O0, because it's extremely effective). Paolo
