Merge pull request swiftlang#29841 from eeckstein/revert-inliner-change

Author: swift-ci

lib/SILOptimizer/Transforms/PerformanceInliner.cpp

@@ -526,15 +526,6 @@ bool SILPerformanceInliner::isProfitableToInline(
   return true;
 }
 
-static bool returnsClosure(SILFunction *F) {
-  for (SILBasicBlock &BB : *F) {
-    if (auto *RI = dyn_cast<ReturnInst>(BB.getTerminator())) {
-      return isa<PartialApplyInst>(RI->getOperand());
-    }
-  }
-  return false;
-}
-
 /// Checks if a given generic apply should be inlined unconditionally, i.e.
 /// without any complex analysis using e.g. a cost model.
 /// It returns true if a function should be inlined.
@@ -579,13 +570,6 @@ static Optional<bool> shouldInlineGeneric(FullApplySite AI) {
     return None;
   }
 
-  // The returned partial_apply of a thunk is most likely being optimized away
-  // if inlined. Because some thunks cannot be specialized (e.g. if an opened
-  // existential is in the subsitution list), we inline such thunks also in case
-  // they are generic.
-  if (Callee->isThunk() && returnsClosure(Callee))
-    return true;
-
   // All other generic functions should not be inlined if this kind of inlining
   // is disabled.
   if (!EnableSILInliningOfGenerics)