Hi all, I've been building GCC from source for GCC Explorer[1]. To that end I've modified a script I've used at work for many years to build GCC. The result is a build script[2], a patch[3] (to get in-tree binutils working on 4.x and 5.x), and a Docker container that allows me a repeatable build of GCC. The script uses an in-tree build of the latest binutils (2.27). It correctly builds GCC 6.x and 5.x, but when configured to build 4.9.x I get a failure comparing stages 2 and 3: Comparing stages 2 and 3 warning: gcc/cc1plus-checksum.o differs warning: gcc/cc1-checksum.o differs Bootstrap comparison failure! gold/aarch64.o differs Makefile:28237: recipe for target 'compare' failed I've tried with 4.9.0 through 4.9.4 but to no avail. Can anyone offer any suggestions as to what might be going on? For anyone interested in poking about in an instance and doesn't mind using docker, one can get a shell into a build instance with `docker run -ti mattgodbolt/gcc-builder bash` - the 'build.sh' in there expects a GCC version number. Of course, one can also take a look at the script source[2] which has all the config options I'm passing to configure. Probably the interesting ones are LTO, linker build id and gold (given the error message). Thanks in advance for any help offered! Regards, Matt [1]: https://gcc.godbolt.org/ [2]: https://github.com/mattgodbolt/gcc-explorer-image/blob/master/gcc/build/build.sh [3]: https://gcc.gnu.org/ml/gcc-patches/2015-07/msg01233.html -- Matt