I see some small performance improvements on a few benchmarks, but they
are likely to be due to noise.
The compilation pipeline is very epilogue release friendly at the moment,i.e.
we do not move the epilogue release of a function till very late in the pipeline.
Therefore, this global data flow sort of an overkill. I am going to change
the pass pipeline next so that we can move epilogue releases freely and the data
flow will become useful.
I do not see compilation time increase.
rdar://26446587
This speeds and reduces memory consumption of test cases with large
CFGs. The specific test case that spawned this fix was a large function
with many dictionary assignments:
public func func_0(dictIn : [String : MyClass]) -> [String : MyClass] {
var dictOut : [String : MyClass] = [:]
dictOut["key5000"] = dictIn["key500"]
dictOut["key5010"] = dictIn["key501"]
dictOut["key5020"] = dictIn["key502"]
dictOut["key5030"] = dictIn["key503"]
dictOut["key5040"] = dictIn["key504"]
...
}
This continued for 10k - 20k values.
This commit reduces the compile time by 2.5x and reduces the amount of
memory allocated by ARC by 2.6x (the memory allocation number includes
memory that is subsequently freed).
rdar://24350646
(libraries now)
It has been generally agreed that we need to do this reorg, and now
seems like the perfect time. Some major pass reorganization is in the
works.
This does not have to be the final word on the matter. The consensus
among those working on the code is that it's much better than what we
had and a better starting point for future bike shedding.
Note that the previous organization was designed to allow separate
analysis and optimization libraries. It turns out this is an
artificial distinction and not an important goal.
