Re:Comparing the Cost of Different Multiple-return Technique...
by pcwalton on Monday December 23, 2013 @01:37PM
(#6955764)
In LLVM, internalized functions (which get created in LTO mode) are converted to fastcall. So yes, the ABI becomes smarter in that case.
The platform ABIs mostly are the way they are for backwards compatibility at this point. They aren't particularly efficient and have weird corner cases (e.g. complex numbers are treated differently than the equivalent struct, IIRC). On x86-64 the situation is a little better, but still not ideal.
The platform ABIs mostly are the way they are for backwards compatibility at this point. They aren't particularly efficient and have weird corner cases (e.g. complex numbers are treated differently than the equivalent struct, IIRC). On x86-64 the situation is a little better, but still not ideal.