SIL: streamline Operand Sequence APIs

* remove `filterUsers(ofType:)`, because it's a duplication of `users(ofType:)`
* rename `filterUses(ofType:)` -> `filter(usersOfType:)`
* rename `ignoreUses(ofType:)` -> `ignore(usersOfType:)`
* rename `getSingleUser` -> `singleUser`
* implement `singleUse` with `Sequence.singleElement`
* implement `ignoreDebugUses` with `ignore(usersOfType:)`

This is a follow-up of eb1d5f484c.

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/AllocBoxToStack.swift

@@ -363,7 +363,7 @@ private func createAllocStack(for allocBox: AllocBoxInst, flags: Flags, _ contex
                                      isLexical: flags.isLexical,
                                      isFromVarDecl: flags.isFromVarDecl)
   let stackLocation: Value
-  if let mu = allocBox.uses.getSingleUser(ofType: MarkUninitializedInst.self) {
+  if let mu = allocBox.uses.singleUser(ofType: MarkUninitializedInst.self) {
     stackLocation = builder.createMarkUninitialized(value: asi, kind: mu.kind)
   } else {
     stackLocation = asi
@@ -484,7 +484,7 @@ private func hoistMarkUnresolvedInsts(stackAddress: Value,
     builder = Builder(atBeginOf: stackAddress.parentBlock, context)
   }
   let mu = builder.createMarkUnresolvedNonCopyableValue(value: stackAddress, checkKind: checkKind,  isStrict: false)
-  stackAddress.uses.ignore(user: mu).ignoreDebugUses.ignoreUses(ofType: DeallocStackInst.self)
+  stackAddress.uses.ignore(user: mu).ignoreDebugUses.ignore(usersOfType: DeallocStackInst.self)
     .replaceAll(with: mu, context)
 }
 

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/ConstantCapturePropagation.swift

@@ -233,7 +233,7 @@ private func rewritePartialApply(_ partialApply: PartialApplyInst, withSpecializ
   // leave the key path itself out of the dependency chain, and introduce dependencies on those
   // operands instead, so that the key path object itself can be made dead.
   for md in newClosure.uses.users(ofType: MarkDependenceInst.self) {
-    if md.base.uses.getSingleUser(ofType: PartialApplyInst.self) == partialApply {
+    if md.base.uses.singleUser(ofType: PartialApplyInst.self) == partialApply {
       md.replace(with: newClosure, context)
     }
   }

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/DestroyHoisting.swift

@@ -83,7 +83,7 @@ let destroyHoisting = FunctionPass(name: "destroy-hoisting") {
 private func optimize(value: Value, _ context: FunctionPassContext) {
   guard value.ownership == .owned,
         // Avoid all the analysis effort if there are no destroys to hoist.
-        !value.uses.filterUses(ofType: DestroyValueInst.self).isEmpty
+        !value.uses.filter(usersOfType: DestroyValueInst.self).isEmpty
   else {
     return
   }

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/InitializeStaticGlobals.swift

@@ -478,7 +478,7 @@ private struct InitValueBuilder: AddressDefUseWalker {
       case .PrepareInitialization:
         return .continueWalk
       case .AddressOfRawLayout:
-        if let addr2Ptr = bi.uses.getSingleUser(ofType: PointerToAddressInst.self) {
+        if let addr2Ptr = bi.uses.singleUser(ofType: PointerToAddressInst.self) {
           return walkDownUses(ofAddress: addr2Ptr, path: path)
         }
         return .abortWalk

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/TempRValueElimination.swift

@@ -83,7 +83,7 @@ private func tryEliminate(copy: CopyLikeInstruction, keepDebugInfo: Bool, _ cont
     removeDestroys(of: allocStack, context)
   }
 
-  allocStack.uses.ignoreUses(ofType: DeallocStackInst.self).replaceAll(with: copy.sourceAddress, context)
+  allocStack.uses.ignore(usersOfType: DeallocStackInst.self).replaceAll(with: copy.sourceAddress, context)
 
   if keepDebugInfo {
     Builder(before: copy, context).createDebugStep()
@@ -247,7 +247,7 @@ private extension AllocStackInst {
     var liferange = InstructionRange(begin: self, context)
     defer { liferange.deinitialize() }
 
-    liferange.insert(contentsOf: uses.ignoreUses(ofType: DeallocStackInst.self).lazy.map { $0.instruction })
+    liferange.insert(contentsOf: uses.ignore(usersOfType: DeallocStackInst.self).lazy.map { $0.instruction })
 
     for use in uses {
       switch use.instruction {

SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyAllocStack.swift

@@ -207,7 +207,7 @@ private extension AllocStackInst {
           iea.replace(with: newAlloc, context)
         }
       case let oea as OpenExistentialAddrInst:
-        assert(oea.uses.ignoreUses(ofType: DestroyAddrInst.self).isEmpty)
+        assert(oea.uses.ignore(usersOfType: DestroyAddrInst.self).isEmpty)
         oea.replace(with: newAlloc, context)
       case let cab as CheckedCastAddrBranchInst:
         let builder = Builder(before: cab, context)
@@ -247,7 +247,7 @@ private extension AllocStackInst {
            is DebugValueInst:
         break
       case let oea as OpenExistentialAddrInst:
-        if !oea.uses.ignoreUses(ofType: DestroyAddrInst.self).isEmpty {
+        if !oea.uses.ignore(usersOfType: DestroyAddrInst.self).isEmpty {
           return nil
         }
       case let iea as InitExistentialAddrInst:

SwiftCompilerSources/Sources/Optimizer/InstructionSimplification/SimplifyBeginAndLoadBorrow.swift

@@ -29,7 +29,7 @@ extension BeginBorrowInst : OnoneSimplifiable, SILCombineSimplifiable {
 
 extension LoadBorrowInst : Simplifiable, SILCombineSimplifiable {
   func simplify(_ context: SimplifyContext) {
-    if uses.ignoreDebugUses.ignoreUses(ofType: EndBorrowInst.self).isEmpty {
+    if uses.ignoreDebugUses.ignore(usersOfType: EndBorrowInst.self).isEmpty {
       context.erase(instructionIncludingAllUsers: self)
       return
     }
@@ -52,7 +52,7 @@ extension LoadBorrowInst : Simplifiable, SILCombineSimplifiable {
 
   private func tryCombineWithCopy(_ context: SimplifyContext) {
     let forwardedValue = lookThroughSingleForwardingUses()
-    guard let singleUser = forwardedValue.uses.ignoreUses(ofType: EndBorrowInst.self).singleUse?.instruction,
+    guard let singleUser = forwardedValue.uses.ignore(usersOfType: EndBorrowInst.self).singleUse?.instruction,
           let copy = singleUser as? CopyValueInst,
           copy.parentBlock == self.parentBlock else {
       return
@@ -81,13 +81,13 @@ private func tryReplaceBorrowWithOwnedOperand(beginBorrow: BeginBorrowInst, _ co
 private func removeBorrowOfThinFunction(beginBorrow: BeginBorrowInst, _ context: SimplifyContext) {
   guard let thin2thickFn = beginBorrow.borrowedValue as? ThinToThickFunctionInst,
         // For simplicity don't go into the trouble of removing reborrow phi arguments.
-        beginBorrow.uses.filterUses(ofType: BranchInst.self).isEmpty else
+        beginBorrow.uses.filter(usersOfType: BranchInst.self).isEmpty else
   {
     return
   }
   // `thin_to_thick_function` has "none" ownership and is compatible with guaranteed values.
   // Therefore the `begin_borrow` is not needed.
-  beginBorrow.uses.ignoreUses(ofType: EndBorrowInst.self).replaceAll(with: thin2thickFn, context)
+  beginBorrow.uses.ignore(usersOfType: EndBorrowInst.self).replaceAll(with: thin2thickFn, context)
   context.erase(instructionIncludingAllUsers: beginBorrow)
 }
 
@@ -110,7 +110,7 @@ private func tryReplaceCopy(
   withCopiedOperandOf beginBorrow: BeginBorrowInst,
   _ context: SimplifyContext
 ) -> Bool {
-  guard let singleUser = forwardedValue.uses.ignoreUses(ofType: EndBorrowInst.self).singleUse?.instruction,
+  guard let singleUser = forwardedValue.uses.ignore(usersOfType: EndBorrowInst.self).singleUse?.instruction,
         let copy = singleUser as? CopyValueInst,
         copy.parentBlock == beginBorrow.parentBlock else {
     return false
@@ -153,7 +153,7 @@ private extension Value {
   /// ```
   /// Returns self if this value has no uses which are ForwardingInstructions.
   func lookThroughSingleForwardingUses() -> Value {
-    if let singleUse = uses.ignoreUses(ofType: EndBorrowInst.self).singleUse,
+    if let singleUse = uses.ignore(usersOfType: EndBorrowInst.self).singleUse,
        let fwdInst = singleUse.instruction as? (SingleValueInstruction & ForwardingInstruction),
        fwdInst.canConvertToOwned,
        fwdInst.isSingleForwardedOperand(singleUse),
@@ -165,17 +165,17 @@ private extension Value {
   }
 
   var allUsesCanBeConvertedToOwned: Bool {
-    let relevantUses = uses.ignoreUses(ofType: EndBorrowInst.self)
+    let relevantUses = uses.ignore(usersOfType: EndBorrowInst.self)
     return relevantUses.allSatisfy { $0.canAccept(ownership: .owned) }
   }
 
   func isDestroyed(after nonDestroyUser: Instruction) -> Bool {
-    return uses.getSingleUser(notOfType: DestroyValueInst.self) == nonDestroyUser &&
+    return uses.singleUser(notOfType: DestroyValueInst.self) == nonDestroyUser &&
            nonDestroyUser.dominates(destroysOf: self)
   }
 
   func replaceAllDestroys(with replacement: Value, _ context: SimplifyContext) {
-    uses.filterUses(ofType: DestroyValueInst.self).replaceAll(with: replacement, context)
+    uses.filter(usersOfType: DestroyValueInst.self).replaceAll(with: replacement, context)
   }
 }
 
@@ -187,7 +187,7 @@ private extension Instruction {
       // The value and instruction are in the same block. All uses are dominated by both.
       return true
     }
-    let destroys = value.uses.filterUses(ofType: DestroyValueInst.self)
+    let destroys = value.uses.filter(usersOfType: DestroyValueInst.self)
     return destroys.allSatisfy({ $0.instruction.parentBlock == parentBlock})
   }
 }

SwiftCompilerSources/Sources/Optimizer/ModulePasses/MandatoryPerformanceOptimizations.swift

@@ -406,7 +406,7 @@ private extension Value {
       //   var p = Point(x: 10, y: 20)
       //   let o = UnsafePointer(&p)
       // Therefore ignore the `end_access` use of a `begin_access`.
-      let relevantUses = singleUseValue.uses.ignoreDebugUses.ignoreUses(ofType: EndAccessInst.self)
+      let relevantUses = singleUseValue.uses.ignoreDebugUses.ignore(usersOfType: EndAccessInst.self)
 
       guard let use = relevantUses.singleUse else {
         return nil

SwiftCompilerSources/Sources/Optimizer/ModulePasses/StackProtection.swift

@@ -361,7 +361,7 @@ private struct StackProtectionOptimization {
     let builder = Builder(after: beginAccess, location: beginAccess.location.asAutoGenerated, context)
     let temporary = builder.createAllocStack(beginAccess.type)
 
-    beginAccess.uses.ignoreUses(ofType: EndAccessInst.self).replaceAll(with: temporary, context)
+    beginAccess.uses.ignore(usersOfType: EndAccessInst.self).replaceAll(with: temporary, context)
 
     for endAccess in beginAccess.endInstructions {
       let endBuilder = Builder(before: endAccess, location: endAccess.location.asAutoGenerated, context)

SwiftCompilerSources/Sources/Optimizer/Utilities/OptUtils.swift

@@ -432,7 +432,7 @@ extension Instruction {
       case .USubOver:
         // Handle StringObjectOr(tuple_extract(usub_with_overflow(x, offset)), bits)
         // This pattern appears in UTF8 String literal construction.
-        if let tei = bi.uses.getSingleUser(ofType: TupleExtractInst.self),
+        if let tei = bi.uses.singleUser(ofType: TupleExtractInst.self),
            tei.isResultOfOffsetSubtract {
           return true
         }
@@ -446,7 +446,7 @@ extension Instruction {
       // Handle StringObjectOr(tuple_extract(usub_with_overflow(x, offset)), bits)
       // This pattern appears in UTF8 String literal construction.
       if tei.isResultOfOffsetSubtract,
-         let bi = tei.uses.getSingleUser(ofType: BuiltinInst.self),
+         let bi = tei.uses.singleUser(ofType: BuiltinInst.self),
          bi.id == .StringObjectOr {
         return true
       }

SwiftCompilerSources/Sources/Optimizer/Utilities/OwnershipLiveness.swift

@@ -717,7 +717,7 @@ extension InteriorUseWalker: AddressUseVisitor {
       if handleInner(borrowed: sb) == .abortWalk {
         return .abortWalk
       }
-      return sb.uses.filterUses(ofType: EndBorrowInst.self).walk {
+      return sb.uses.filter(usersOfType: EndBorrowInst.self).walk {
         useVisitor($0)
       }
     case let load as LoadBorrowInst:

SwiftCompilerSources/Sources/SIL/Operand.swift

@@ -143,16 +143,7 @@ extension Sequence where Element == Operand {
     self.lazy.map { $0.value }
   }
 
-  public var singleUse: Operand? {
+  public var singleUse: Operand? { singleElement }
-    var result: Operand? = nil
-    for op in self {
-      if result != nil {
-        return nil
-      }
-      result = op
-    }
-    return result
-  }
 
   public var isSingleUse: Bool { singleUse != nil }
 
@@ -161,18 +152,14 @@ extension Sequence where Element == Operand {
   }
 
   public var ignoreDebugUses: LazyFilterSequence<Self> {
-    self.lazy.filter { !($0.instruction is DebugValueInst) }
+    ignore(usersOfType: DebugValueInst.self)
   }
 
-  public func filterUses<I: Instruction>(ofType: I.Type) -> LazyFilterSequence<Self> {
+  public func filter<I: Instruction>(usersOfType: I.Type) -> LazyFilterSequence<Self> {
     self.lazy.filter { $0.instruction is I }
   }
 
-  public func filterUsers<I: Instruction>(ofType: I.Type) -> LazyMapSequence<LazyFilterSequence<Self>, I> {
+  public func ignore<I: Instruction>(usersOfType: I.Type) -> LazyFilterSequence<Self> {
-    self.lazy.filter { $0.instruction is I }.lazy.map { $0.instruction as! I }
-  }
-
-  public func ignoreUses<I: Instruction>(ofType: I.Type) -> LazyFilterSequence<Self> {
     self.lazy.filter { !($0.instruction is I) }
   }
 
@@ -180,12 +167,12 @@ extension Sequence where Element == Operand {
     self.lazy.filter { !($0.instruction == user) }
   }
 
-  public func getSingleUser<I: Instruction>(ofType: I.Type) -> I? {
+  public func singleUser<I: Instruction>(ofType: I.Type) -> I? {
-    filterUses(ofType: I.self).singleUse?.instruction as? I
+    filter(usersOfType: I.self).singleUse?.instruction as? I
   }
 
-  public func getSingleUser<I: Instruction>(notOfType: I.Type) -> Instruction? {
+  public func singleUser<I: Instruction>(notOfType: I.Type) -> Instruction? {
-    ignoreUses(ofType: I.self).singleUse?.instruction
+    ignore(usersOfType: I.self).singleUse?.instruction
   }
 
   public var endingLifetime: LazyFilterSequence<Self> {

SwiftCompilerSources/Sources/SIL/Utilities/BorrowUtils.swift

@@ -300,7 +300,7 @@ public enum BorrowingInstruction : CustomStringConvertible, Hashable {
 extension BorrowingInstruction {
   private func visitEndBorrows(value: Value, _ context: Context, _ visitor: @escaping (Operand) -> WalkResult)
     -> WalkResult {
-    return value.lookThroughBorrowedFromUser.uses.filterUses(ofType: EndBorrowInst.self).walk {
+    return value.lookThroughBorrowedFromUser.uses.filter(usersOfType: EndBorrowInst.self).walk {
       visitor($0)
     }
   }

SwiftCompilerSources/Sources/SIL/Utilities/PhiUpdater.swift

@@ -137,7 +137,7 @@ private func createEmptyBorrowedFrom(for phi: Phi, _ context: some MutatingConte
   }
   let builder = Builder(atBeginOf: phi.value.parentBlock, context)
   let bfi = builder.createBorrowedFrom(borrowedValue: phi.value, enclosingValues: [])
-  phi.value.uses.ignoreUses(ofType: BorrowedFromInst.self).replaceAll(with: bfi, context)
+  phi.value.uses.ignore(usersOfType: BorrowedFromInst.self).replaceAll(with: bfi, context)
 }
 
 /// Replaces a phi with the unique incoming value if all incoming values are the same: