PerformanceInliner: enable generic inlining of co-routines

[eeckstein]

Co-routines are so expensive (e.g. Array.subscript.read) that it makes sense to enable generic inlining of co-routines.
This will speed up array iteration (e.g. for elem in array { }) in a generic context significantly.
Another example is ManagedBuffer.header.read, which gets much faster.
In both cases, the speedup is mainly because there is no malloc happening anymore.

https://bugs.swift.org/browse/SR-11231
rdar://problem/53777612

[eeckstein]

@swift-ci test

[eeckstein]

@swift-ci benchmark

[swift-ci]

Performance: -O

Regression	OLD	NEW	DELTA	RATIO
PrefixWhileAnySeqCntRangeLazy	34	40	+17.6%	0.85x (?)
Improvement	OLD	NEW	DELTA	RATIO
Dictionary4	198	156	-21.2%	1.27x
Dictionary4OfObjects	225	197	-12.4%	1.14x

Code size: -O

Regression	OLD	NEW	DELTA	RATIO
BucketSort.o	11083	11339	+2.3%	0.98x

Performance: -Osize

Regression	OLD	NEW	DELTA	RATIO
MapReduce	218	262	+20.2%	0.83x (?)
RandomShuffleLCG2	368	416	+13.0%	0.88x
RemoveWhereSwapInts	31	35	+12.9%	0.89x
Array2D	3696	4144	+12.1%	0.89x (?)
MapReduceAnyCollection	239	261	+9.2%	0.92x
RemoveWhereFilterInts	23	25	+8.7%	0.92x (?)
SubstringFromLongStringGeneric	12	13	+8.3%	0.92x (?)
ArraySetElement	262	283	+8.0%	0.93x (?)
Improvement	OLD	NEW	DELTA	RATIO
FlattenListLoop	2791	2416	-13.4%	1.16x (?)
ObjectiveCBridgeStubNSDateRefAccess	196	174	-11.2%	1.13x (?)

Code size: -Osize

Regression	OLD	NEW	DELTA	RATIO
StringRemoveDupes.o	4529	4641	+2.5%	0.98x
BucketSort.o	11169	11393	+2.0%	0.98x

Performance: -Onone

Code size: -swiftlibs

How to read the data

The tables contain differences in performance which are larger than 8% and differences in code size which are larger than 1%.

If you see any unexpected regressions, you should consider fixing the
regressions before you merge the PR.

Noise: Sometimes the performance results (not code size!) contain false
alarms. Unexpected regressions which are marked with '(?)' are probably noise.
If you see regressions which you cannot explain you can try to run the
benchmarks again. If regressions still show up, please consult with the
performance team (@eeckstein).

Hardware Overview

  Model Name: Mac mini
  Model Identifier: Macmini8,1
  Processor Name: Intel Core i7
  Processor Speed: 3.2 GHz
  Number of Processors: 1
  Total Number of Cores: 6
  L2 Cache (per Core): 256 KB
  L3 Cache: 12 MB
  Memory: 64 GB

[swift-ci]

Build failed
Swift Test Linux Platform
Git Sha - 8c04047435d7fa5539afc9be0a6ad540c4f826c0

[swift-ci]

Build failed
Swift Test OS X Platform
Git Sha - 8c04047435d7fa5539afc9be0a6ad540c4f826c0

[eeckstein]

@swift-ci test

[eeckstein]

@swift-ci test

[swift-ci]

Build failed
Swift Test Linux Platform
Git Sha - d07593b

[swift-ci]

Build failed
Swift Test OS X Platform
Git Sha - d07593b

[eeckstein]

@swift-ci test