There's an issue with LLVM metadata support; it triggers an assert when trying to generate asm for code with metadata globals. This new pass is used as a workaround: it strips metadata from the module before it reaches the code generator. Obviously, this is disabled if LLVM doesn't support metadata.

LLVM D Compiler (LDC)

This compiler is based on the Digital Mars D (DMD) compiler frontend, and
the LLVM compiler toolkit. See LICENSE for licensing information.

For more information, including build instructions, visit the LDC website:

http://www.dsource.org/projects/llvmdc