[llvm-dev] For the LLVM wishlist

[Joerg Sonnenberger via llvm-dev]

On Fri, Apr 15, 2016 at 05:22:12PM +0200, ardi via llvm-dev wrote:
> On 4/15/16, Joerg Sonnenberger via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> > On Fri, Apr 15, 2016 at 02:31:59PM +0200, ardi via llvm-dev wrote:
> >> On Fri, Apr 15, 2016 at 1:02 PM, Joerg Sonnenberger via llvm-dev
> >> <llvm-dev at lists.llvm.org> wrote:
> >> > On Fri, Apr 15, 2016 at 10:45:03AM +0200, ardi via llvm-dev wrote:
> >> >> What I found is that the build system is really complex, performs many
> >> >> checks, and quite often takes wrong decisions (example: a fatal error
> >> >> if the OS X version is older than 10.7, instead of just disabling
> >> >> sanitizers and continuing with the build --moreover, if you manually
> >> >> disable the sanitizers build, its tests are not disabled at make
> >> >> check-all, so you end up with many tests failing because of a
> >> >> component you didn't build).
> >> >
> >> > Huh? If you check out only llvm and clang, nothing is checked for the
> >> > sanitizers, they don't get built and they don't get tested.
> >>
> >> But if you don't check out compiler-rt, you don't get builtins.
> >> Missing the feature of getting highly optimized code output is a big
> >> miss, IMHO. And I don't think builtins require anything apart from a
> >> standard compiler.
> >
> > On most platforms you don't need compiler-rt except for the sanitizers.
> 
> Wait, do you mean that builtins for processors like x86_64 or PowerPC
> aren't being used by clang? I understood builtins were a key lib for
> getting maximum performance on the processors it supports, but maybe I
> misunderstood it.

Few builtins are lowered to libcalls on x86_64 and powerpc and those are
normally provided e.g. by libgcc already.

Joerg