swift234

Enable mandatory inlining of generic functions with unbound generic types.

This allows us to inline @transparent functions in cases like this:

  @transparent
  func partial<T, U>(x: T, f: (T) -> U) -> U {
    return f(x)
  }

  func applyPartial<U>(x: Int32, f: (Int32) -> U) -> U {
    return partial(x, f)
  }

I had planned on enabling this same behavior in the performance inliner
first in order to be able to test the underlying functionality more
thoroughly, but I hit a blocking issue pretty quickly in type
lowering (rdar://problem/19387372).

Given that @transparent is not currently user-facing, it seems
reasonable to go ahead and enable this now and fix any new issues it
exposes since it should be easy to work around those issues by not using
@transparent.

There were lots of performance differences as a result of this change,
mostly positive. Below I list the 10 largest improvements for each of
-Onone, -O, and -Ounchecked, along with all regressions greater than
10%. I will be opening radars for these.

-Onone
---------------------------------------
ArrayOfPOD                     104.200%
ArrayOfGenericPOD               40.700%
TwoSum                          37.800%
EditDistance                    35.600%
GenericStack                    33.500%
SwiftStructuresStack            29.700%
SwiftStructuresInsertionSort    29.300%
Havlak                          27.200%
NestedLoop                      26.800%
Life                            26.400%

SwiftStructuresTrie            -15.500%

-O
---------------------------------------
TwoSum                          46.200%
GenericStack                    37.900%
SwiftStructuresStack            37.100%
Dictionary                      30.200%
Forest                          27.800%
NSDictionaryImplicitConversion  24.400%
Prims                           23.500%
Dictionary2                     19.600%
DollarFilter                    17.00%
SwiftStructuresQueue            16.600%

NSStringConversion             -22.600%
SwiftStructuresTrie            -25.900%
PopFrontArray                  -44.100%

-Ounchecked
---------------------------------------
SwiftStructuresStack            38.900%
GenericStack                    37.400%
NSDictionaryImplicitConversion  21.200%
TwoSum                          20.500%
Histogram                       16.600%
DollarFilter                    15.900%
DollarFunction                  13.600%
ArrayLiteral                    12.900%
Forest                          12.300%
Prims                           10.300%

ImageProc                      -10.900%
InsertionSort                  -11.200%
StrToInt                       -11.800%
NBody                          -14.900%
SwiftStructuresTrie            -29.900%

Swift SVN r24263