[LLVMdev] some llvm/clang missed optimizations
regehr at cs.utah.edu
Tue Jan 26 17:55:53 PST 2010
>> Repetitive code with lots of bitwise operations is compiled by LLVM into
>> much larger code than the other compilers:
>> Note that this is straight-line code, so LLVM's output will run 4-5
>> times longer than everyone else's.
>> I'll be interested to learn the source of this one.
> This looks like a one-off case; instcombine destroys the symmetry of
> the code that the test harness duplicated by reducing the masking
> constants. Probably too complicated for too little gain to be worth
There are a bunch of these actually, I can try to make a list...
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