I disassembled all libraries and binaries in all riscv64 debian packages and counted how often each individual instruction is used: http://svn.clifford.at/handicraft/2018/rvinsfreq/combined.txt … (The most frequently used instruction is "http://c.mv ", followed by "auipc", "addi", and "jal".)
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Yes that’s true. To find macro-op fusion pairs in existing code we’d need to find dependent pairs that overwrite a temporary potentially separated by other instructions. There would need to be micro-arch options in the compiler to optimise for processors with macro-op fusion.
That's what I did in the analysis I did last year on fusion options for neg and not: http://svn.clifford.at/handicraft/2017/bitcode/notneg.py … uses some heuristics because it does not follow branches, and it keeps track of branch targets to avoid false positives that span basic blocks.
