MLton runs fine on the PowerPC64 architecture.
When compiling for PowerPC64, MLton targets the 64-bit PowerPC architecture.
When compiling for PowerPC64, MLton doesn’t support native code generation (-codegen native). Hence, performance is not as good as it might be and compile times are longer. Also, the quality of code generated by gcc is important. By default, MLton calls gcc -O1. You can change this by calling MLton with -cc-opt -O2.