https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66848
Bug ID: 66848 Summary: boehm-gc fails test suite on x86_64-apple-darwin15 Product: gcc Version: 5.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: boehm-gc Assignee: unassigned at gcc dot gnu.org Reporter: howarth.at.gcc at gmail dot com Target Milestone: --- The boehm-gc test suite in FSF gcc shows regressions at -m32/-m64 when run on x86_64-apple-darwin15... WARNING: program timed out. FAIL: boehm-gc.c/gctest.c -O2 execution test FAIL: boehm-gc.c/thread_leak_test.c -O2 execution test FAIL: boehm-gc.lib/staticrootstest.c -O2 execution test The same regressions are seen when running the boehm-gc test suite binaries and libraries, built entirely on x86_64-apple-darwin14, on x86_64-apple-darwin15. Replacing the libunwind.dylib on x86_64-apple-darwin15 with one from x86_64-apple-darwin14 eliminates the boehm-gc test suite regressions. This issue has been opened as radr://21372179, "the FSF boehm-gc library built on 10.10 fails to pass its tests on 10.11". The Apple programmers claim the sources for libunwind.dylib are unchanged between darwin14 and darwin15. The only difference is the use of the darwin15 SDK and the Xcode 7 clang compilers. They believe the optimizations applied by the newer clang compiler are safe (which seems to be supported by the fact that upstream boehm-gc from http://www.hboehm.info/gc/ shows no test suite failures when built and run under x86_64-apple-darwin15 with Xcode 7). Rather, they suspect we are tripping over a latent bug in the FSF gcc boehm-gc sources.