Mathieu Desnoyers wrote:
I am not saying that the standard marker will have to inhibit optimizations. Actually, it's the contrary : a well-thought marker should _not_ modify that kind of optimization, and we should put markers in code locations less likely to inhibit gcc optimizations. However, in the case where we happen to be interested in information otherwise optimized away by GCC, it makes sense to inhibit this optimization in order to have the information available for tracing. I expect this to happen rarely, but I think we must deal with optimizations to make sure we never trace garbage due to some unexpected gcc optimization. I think it's a small (e.g. undetectable at the macrobenchmark level) price to pay to get correct tracing information.
That's a pretty flippant reply... liveness causes register pressure which can cause rapid degradation in code quality on a register-starved architecture like x86.
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