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