Ian Lance Taylor <i...@google.com> writes: > On Thu, Mar 13, 2014 at 6:27 PM, Michael Hudson-Doyle > <michael.hud...@linaro.org> wrote: >> Ian Lance Taylor <i...@google.com> writes: >> >>> The bug report http://golang.org/issue/7074 shows that math.Log2(1) >>> produces the wrong result on Aarch64, because the Go math package is >>> compiled to use a fused multiply-add instruction. This patch to the >>> libgo configure script will use -ffp-contract=off when compiling the >>> math package on processors other than x86. Bootstrapped and ran Go >>> testsuite on x86_64-unknown-linux-gnu, not that that tests much. >>> Committed to mainline. >> >> Thanks for this! If you are willing to go into battle enough to argue >> that libgcc should also be compiled with -ffp-contract=off (I did not >> have the stomach for that fight) then we'll be down to 1 check-go >> failure on aarch64 (which is peano -- due to the absence of >> split/copyable stacks and should probably xfail). > > Hmmm, what is it that fails with libgcc? Is there a bug report for > it?
https://code.google.com/p/go/issues/detail?id=7066 and then http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59714 I wanted to propose a version using "Kahan's algorithm for the determinant" as described in http://hal-ens-lyon.archives-ouvertes.fr/docs/00/78/57/86/PDF/Jeannerod_Louvet_Muller_final.pdf but I haven't gotten around to it... Cheers, mwh > I agree that peano is likely to fail without split stacks. > > Ian