[x86_64] Unimplemented conversions
When trying to run test_pypy.py on develop, for some reason I am know longer running out of memory, instead I get the following error:
thread '<unnamed>' panicked at 'not yet implemented', src/compiler/backend/arch/x86_64/inst_sel.rs:1352
It seems that BITCAST, FPTRUNC and FPEXT are the only unimplemented conversion ops on x86-64. This should be fixed (the aarch64 backend implements them by emitting single assembly instructions, hopefully there are equivalent instructions for x86-64).