disable pass tree-ifcombine

Stream: general

[Mario Carneiro]

I just tried to compile lean for the first time in a while, and I'm getting these ifcombine warnings. Does anyone know what this is about? lean#77 looks kind of related but I'm not on fedora.

$ ninja
[0/1] Re-running CMake...
-- Lean library will be installed at /usr/local/lib/lean
-- Using standard malloc.
-- git commit sha1: 37a8b750b60fcda9cd11b0a2a183d7f0d3ecec5c
-- Configuring done
-- Generating done
-- Build files have been written to: /home/mario/Documents/lean/lean/build
[1/61] Building CXX object tests/util/CMakeFiles/scoped_map.dir/scoped_map.cpp.o
cc1plus: note: disable pass tree-ifcombine for functions in the range of [0, 4294967295]
[2/61] Building CXX object tests/util/CMakeFiles/worker_queue.dir/worker_queue.cpp.o
cc1plus: note: disable pass tree-ifcombine for functions in the range of [0, 4294967295]
[5/61] Building CXX object tests/util/CMakeFiles/name.dir/name.cpp.o
cc1plus: note: disable pass tree-ifcombine for functions in the range of [0, 4294967295]
[7/61] Building CXX object tests/util/CMakeFiles/serializer.dir/serializer.cpp.o
cc1plus: note: disable pass tree-ifcombine for functions in the range of [0, 4294967295]
[9/61] Building CXX object tests/util/CMakeFiles/lru_cache.dir/lru_cache.cpp.o
cc1plus: note: disable pass tree-ifcombine for functions in the range of [0, 4294967295]

[Gabriel Ebner]

This is a workaround for an old gcc miscompilation bug.

[Mario Carneiro]

g++ --version gives 9.3.0 if that helps

[Gabriel Ebner]

    # TODO(Vtec234): Add upper bound when GCC with a fix is released
    elseif (GCC_VERSION VERSION_GREATER 9.1 OR GCC_VERSION VERSION_EQUAL 9.1)
        # Work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91597

[Mario Carneiro]

the bug report appears to suggest that this is fixed in 9.3