LLVM passes for compiling Rust code with Emscripten. The code could use some cleanup, but it more or less works. Currently it appears only -remove-overflow-checks and -remove-assume are needed. Otherwise, upstream emscripten-fastcomp (version 1.29.0) works.

Compile with:

make RemoveOverflowChecks.so RemoveAssume.so \
    LLVM_PREFIX=.../emscripten-fastcomp/build

Use with:

.../emscripten-fastcomp/build/bin/opt \
    -load=RemoveOverflowChecks.so -load=RemoveAssume.so \
    -O3 -remove-overflow-checks -remove-assume -globaldce \
    input.ll -S -o output.ll