Hi Bruce, thank you for the detailed response. On 14 October 2016 at 01:53, Bruce Evans <b...@optusnet.com.au> wrote: >> compiler-rt's complex division support routines contain calls to >> compiler builtins such as `__builtin_scalbnl`. Unfortunately Clang >> turns these back into a call to `scalbnl`. > > gcc-4.2 has the same bug.
Oh, interesting. Do you know off hand if it's resolved in later GCC? It seems particularly unfortunate for the compiler to report (by whatever mechanism) that a builtin exists, and then just turn that builtin into a library call. >> For now link libm's C version of the required support routines. > > Even libm doesn't use these in some cases. i386 mostly uses asm > versions. Hopefully the rt division routines don't need to be efficient > because they are rarely called. Most likely I'll switch to the asm versions across suitable architectures in a subsequent change, mirroring the choices made in libm. I just wanted to get a version in, to enable further testing (ports exp-runs, etc.) of this libunwind / compiler-rt combination. [Details about specific groups of functions omitted -- I'll try to take a look at these later.] > libcompiler_rt.a now on amd64 now has the following namespace bugs: > > U compilerrt_abort_impl > U fflush > U fprintf > U mprotect > U sysconf > U fmaxl > U logbl > U scalbnl > U logbf > U scalbnf > U logb > U scalbn > U abort > > These are bugs since division must be available with -ffreestanding and > the freestanding library shouldn't have to reimplement it. Yes, these libcompiler_rt.a issues seem rather surprising to me, but presumably they aren't causing much of an issue in practice in the static lib. In any case, my hope is that once I try disentangling these libraries I can take a look at these issues across the set of libraries (libcompiler_rt.a aka libgcc.a, libgcc_eh.a, libgcc_s.so). _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
