Fix performance regression

Author: Ben Ng

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -180,7 +180,6 @@ void addHighLevelLoopOptPasses(SILPassPipelinePlan &P) {
   P.addSimplifyCFG();
   P.addPerformanceConstantPropagation();
   P.addSimplifyCFG();
-  P.addArrayElementPropagation();
   // End of unrolling passes.
   P.addRemovePins();
   P.addABCOpt();
@@ -295,6 +294,7 @@ static void addHighLevelEarlyLoopOptPipeline(SILPassPipelinePlan &P) {
   P.startPipeline("HighLevel+EarlyLoopOpt");
   // FIXME: update this to be a function pass.
   P.addEagerSpecializer();
+  P.addArrayElementPropagation();
   addSSAPasses(P, OptimizationLevelKind::HighLevel);
   addHighLevelLoopOptPasses(P);
 }

lib/SILOptimizer/Transforms/PerformanceInliner.cpp

@@ -228,7 +228,8 @@ SILFunction *SILPerformanceInliner::getEligibleFunction(FullApplySite AI) {
   // Don't inline functions that are marked with the @_semantics or @effects
   // attribute if the inliner is asked not to inline them.
   if (Callee->hasSemanticsAttrs() || Callee->hasEffectsKind()) {
-    if (WhatToInline == InlineSelection::NoSemanticsAndGlobalInit) {
+    if (WhatToInline == InlineSelection::NoSemanticsAndGlobalInit &&
+      !Callee->hasSemanticsAttr("early_inline")) {
       return nullptr;
     }
     // The "availability" semantics attribute is treated like global-init.

stdlib/public/core/Arrays.swift.gyb

@@ -1338,6 +1338,7 @@ extension ${Self} : RangeReplaceableCollection, _ArrayProtocol {
   ///   bridged `NSArray` instance as its storage, the efficiency is
   ///   unspecified.
   @_semantics("array.append_element")
+  @_semantics("early_inline")
   public mutating func append(_ newElement: Element) {
     _makeUniqueAndReserveCapacityIfNotUnique()
     let oldCount = _getCount()
@@ -1360,6 +1361,7 @@ extension ${Self} : RangeReplaceableCollection, _ArrayProtocol {
   ///
   /// - Complexity: O(*n*), where *n* is the length of the resulting array.
   @_semantics("array.append_contentsOf")
+  @_semantics("early_inline")
   public mutating func append<S : Sequence>(contentsOf newElements: S)
     where S.Iterator.Element == Element {