Merge pull request #67395 from eeckstein/redundant-load-elimination

Optimizer: re-implement the RedundantLoadElimination pass in Swift

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/Analysis/AliasAnalysis.swift

@@ -36,7 +36,7 @@ struct AliasAnalysis {
   static func register() {
     BridgedAliasAnalysis.registerAnalysis(
       // getMemEffectsFn
-      { (bridgedCtxt: BridgedPassContext, bridgedVal: BridgedValue, bridgedInst: BridgedInstruction) -> swift.MemoryBehavior in
+      { (bridgedCtxt: BridgedPassContext, bridgedVal: BridgedValue, bridgedInst: BridgedInstruction, complexityBudget: Int) -> swift.MemoryBehavior in
         let context = FunctionPassContext(_bridged: bridgedCtxt)
         let inst = bridgedInst.instruction
         let val = bridgedVal.value
@@ -47,7 +47,8 @@ struct AliasAnalysis {
         case let builtin as BuiltinInst:
           return getMemoryEffect(ofBuiltin: builtin, for: val, path: path, context).bridged
         default:
-          if val.at(path).isEscaping(using: EscapesToInstructionVisitor(target: inst, isAddress: true), context) {
+          if val.at(path).isEscaping(using: EscapesToInstructionVisitor(target: inst, isAddress: true),
+                                     complexityBudget: complexityBudget, context) {
             return .MayReadWrite
           }
           return .None

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CMakeLists.txt

@@ -17,6 +17,7 @@ swift_compiler_sources(Optimizer
   ObjCBridgingOptimization.swift
   MergeCondFails.swift
   NamedReturnValueOptimization.swift
+  RedundantLoadElimination.swift
   ReleaseDevirtualizer.swift
   SimplificationPasses.swift
   StackPromotion.swift

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DeadStoreElimination.swift

@@ -88,7 +88,7 @@ private func tryEliminate(store: StoreInst, _ context: FunctionPassContext) {
         case .dead:
           // The new individual stores are inserted right after the current store and
           // will be optimized in the following loop iterations.
-          store.split(context)
+          store.trySplit(context)
       }
   }
 }
@@ -158,27 +158,6 @@ private extension StoreInst {
     }
   }
 
-  func split(_ context: FunctionPassContext) {
-    let builder = Builder(after: self, context)
-    let type = source.type
-    if type.isStruct {
-      for idx in 0..<type.getNominalFields(in: parentFunction).count {
-        let srcField = builder.createStructExtract(struct: source, fieldIndex: idx)
-        let destFieldAddr = builder.createStructElementAddr(structAddress: destination, fieldIndex: idx)
-        builder.createStore(source: srcField, destination: destFieldAddr, ownership: storeOwnership)
-      }
-    } else if type.isTuple {
-      for idx in 0..<type.tupleElements.count {
-        let srcField = builder.createTupleExtract(tuple: source, elementIndex: idx)
-        let destFieldAddr = builder.createTupleElementAddr(tupleAddress: destination, elementIndex: idx)
-        builder.createStore(source: srcField, destination: destFieldAddr, ownership: storeOwnership)
-      }
-    } else {
-      fatalError("a materializable projection path should only contain struct and tuple projections")
-    }
-    context.erase(instruction: self)
-  }
-
   var hasValidOwnershipForDeadStoreElimination: Bool {
     switch storeOwnership {
     case .unqualified, .trivial: