Recent libstdc++ regression on i686-linux: abi/cxx_runtime_only_linkage.cc

[Paolo Carlini]

Hi,
> One significant case is where atomic operations are available with kernel 
> help.  SH GNU/Linux provides __sync_* in libgcc and there is an unreviewed 
> patch to do the same for ARM GNU/Linux; both use kernel help in those 
> implementations, and more targets may do this in future.  (It's been 
> proposed for HPPA.  The ColdFire NPTL specification doesn't include 
> exporting such helpers from libgcc but they could easily be exported from 
> libc; the use of a vDSO may make exporting from libgcc harder.)  The 
> GLIBCXX_ENABLE_ATOMIC_BUILTINS configure test looks like it's incorrect 
> for such cases, because it greps for __sync in a .s file and these targets 
> will have such __sync_* references resolved in libgcc.  So on GNU/Linux 
> that configure test ought to be a link test.
>   
For this issue, do you think it would be Ok to the change the current 
open-coded test to the usual GCC_TRY_COMPILE_OR_LINK pattern?

Thanks,
Paolo.