I noticed that ICC 13 on Godbolt compiled it "correctly", assuming correctly means as written. I wondered if this was just because it's an older version that

I noticed that ICC 13 on Godbolt compiled it "correctly", assuming correctly means as written. I wondered if this was just because it's an older version that wasn't yet optimized, so I tried with the current ICC 17 Beta. But with all the optimization options I tried, it stuck to its guns and compiled it as written: 0: c7 07 03 00 00 00 movl $0x3,(%rdi) 6: c7 05 00 00 00 00 04 movl $0x4,0x0(%rip) d: 00 00 00 10: 8b 07 mov (%rdi),%eax 12: c3 retq From what I can tell testing with http://webcompiler.cloudapp.net http://webcompiler.cloudapp.net, MSVC seems to also produce the "correct" result at all optimization settings, while GCC and Clang do so only with -O1 or lower for all versions that I tried.