[llvm-dev] Useless exit instruction in "main", replaceable with return inst

[Friedman, Eli via llvm-dev]

On 4/3/2018 9:24 AM, Dávid Bolvanský via llvm-dev wrote:
> Hi,
>
> LLVM optimizer seems to leave "call exit" instruction in "main" 
> function but it could be replaced by a return instruction.
> Any reason why leave it as is or this simple optimization could be 
> implemented e.g. in SimplifyLibCalls?

The usual answer to this sort of question is "nobody has implemented it 
yet".  And frankly, it's not really worth implementing; a minor size 
reduction on a cold path in main() has very little benefit. (And 
strictly speaking, C allows programs to recursively call main().)

-Eli

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