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Re: Thread-safety of a profiled binary (and GCOV runtime library)

On 07/25/16 08:46, Richard Biener wrote:

There is also the question about optimization - we go great lengths to ensure
that for example loop store motion applies to counter updates so we get

 old_ctr = values[42];
 for (;;)
   ...
 values[42] = old_ctr + # iterations

using atomics there might show that we have no facility to optimize atomics
at all (given their usual semantics is to include some kind of barrier).
Hm, that suggests something along the lines of __builtin_gcov_add() and an associated optimization ... 

nathan
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