1. Not abi compatible 2. Not performant (Relative to other solutions) 3. Would be the odd man out. Literally all other development was on clang/llvm at this p

1. Not abi compatible 2. Not performant (Relative to other solutions) 3. Would be the odd man out. Literally all other development was on clang/llvm at this point. Supporting mingw would have meant duplicating all performance/etc work for GCC. 4. Chrome also wanted other benefits that clang/LLVM would bring them (easy ability to build various forms of refactoring and analysis tooling, etc)