No, asm.js is just "an extraordinarily optimizable, low-level subset of JavaScript". It doesn't run x86 machine code, you'd need to convert it (or interpret it).
According to the webs, there are some x86 → LLVM converters, and then Emscripten can convert LLVM → asm.js, but getting that to work would probably take many months.
According to the webs, there are some x86 → LLVM converters, and then Emscripten can convert LLVM → asm.js, but getting that to work would probably take many months.