This is the mail archive of the
libstdc++@gcc.gnu.org
mailing list for the libstdc++ project.
Re: [PATCH] libstdc++: Allow using <future> without lock free atomic int
- From: Jonathan Wakely <jwakely at redhat dot com>
- To: Christophe Lyon <christophe dot lyon at linaro dot org>
- Cc: Pauli <suokkos at gmail dot com>, "libstdc++ at gcc dot gnu dot org" <libstdc++ at gcc dot gnu dot org>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 4 Jan 2017 15:10:29 +0000
- Subject: Re: [PATCH] libstdc++: Allow using <future> without lock free atomic int
- Authentication-results: sourceware.org; auth=none
- References: <20161109212623.2488-1-suokkos@gmail.com> <20161216175257.GG895@redhat.com> <20161219175227.GP895@redhat.com> <20170103153224.GF895@redhat.com> <20170104110232.GG895@redhat.com> <CAKdteObhKNX2cN=Sp1AwDapx_gCko5uu7xz_GZ78ddw=E1X4dg@mail.gmail.com>
On 04/01/17 16:00 +0100, Christophe Lyon wrote:
Hi Jonathan,
On 4 January 2017 at 12:02, Jonathan Wakely <jwakely@redhat.com> wrote:
On 03/01/17 15:32 +0000, Jonathan Wakely wrote:
Here's what I plan to commit to trunk tomorrow.
Committed to trunk.
After this commit (r244051), I do see improvements, but also a few new failures.
The big picture is at
http://people.linaro.org/~christophe.lyon/cross-validation/gcc/trunk/244051/report-build-info.html
Where the expected improvements for arm-none-eabi, with default cpu&fpu are:
http://people.linaro.org/~christophe.lyon/cross-validation/gcc/trunk/244051/arm-none-eabi/diff-libstdc++-rh60-arm-none-eabi-default-default-default.txt
New failures appear when forcing -march=armv5t in runtestflags (the 3
red items in the 1st report):
- FAIL appears [ => FAIL]:
18_support/exception_ptr/60612-terminate.cc execution test
18_support/exception_ptr/60612-unexpected.cc execution test
30_threads/packaged_task/members/at_thread_exit.cc execution test
30_threads/promise/members/at_thread_exit.cc execution test
Note that in these cases we are compiling the test cases with
-march=armv5t, but link
with libraries built --with-cpu=cortex-a9, so there might be a mismatch?
Yes, this is probably the same issue as PR63829
Richard's comment on the bug report says that arm should always use
atomics, via kernel helpers if necessary, so that there is no ABI
change when using -march for older CPUs.
I don't know how to do that, but I hope we can make some progress on
it for gcc 8.