Revert 159f1c048e08a8780d92858cfc80e723c90235e3 (#173893)
This causes non-determinism in compiles.
From nikic: "FYI the non-determinism is also visible on
llvm-opt-benchmark. Maybe repeatedly running test cases from
https://github.com/dtcxzyw/llvm-opt-benchmark/commit/299446d99f04024d5f569ce1f7e9338c9bcf55fe
could reproduce the issue..."
Also revert dependent 796fafeff92fe5d2d20594859e92607116e30a16 and
e135447bda617125688b71d33480d131d1076a72.
