[llvm-dev] Missed strlen optimizations

[Dávid Bolvanský via llvm-dev]

Hello,

Code: https://godbolt.org/g/EG4Wi6

unsigned fff3(void) {
    char buf[10] = "";
    return strlen(buf);
}

Since we are memset-ing before strlen call, we could replace strlen with
just 0.

Has LLVM any API to get "last instruction before strlen" which modifies
strlen argument "buf"? So we can check "yes, it is memset there, replace
strlen with zero" ?


Thanks
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