Made Equality Tests Smarter#38
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Currently,
==compares the underlying arrays. This compiles tomemcmpin llvm.memcmpis then optimized tobcmp. The problem with this is that llvm-opt doesn't do much with bcmp during the instcombine pass. It will also sometimes write to memory just to read it back again.What I did to work around this in div-rem was use
unreachable_unchecked()calls to tell the compiler that thebcmpis equivalent to twoicmps. I have considered overloading the==operator with abcmpplus hints, but now I believe it is best to not usebcmpat all. Ethnum's integers have public fields, so the current equality operation can always be called witha.0 == b.0.I compared and annotated a few alternatives on Compiler Explorer. Note that I have not considered adding an llvm intrinsic.