Johannes Doerfert 1b6041a9e8 [Attributor] willreturn + noreturn = UB
We gave up on `noreturn` if `willreturn` was known for a while but we
now again try to always derive `noreturn`. This is useful because a
function that is `noreturn` + `willreturn` is basically dead as
executing it would lead to undefined behavior (UB).

This came up in the IPConstantProp cases where a function only contained
a unreachable but was not marked `noreturn` which caused missed
opportunities down the line.
2019-11-02 00:35:22 -05:00
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2019-07-16 15:28:29 +00:00