SwiftCompilerSources: add a few utility APIs

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/DataStructures/Set.swift

@@ -176,3 +176,16 @@ struct InstructionSet : IntrusiveSet {
     context.freeNodeSet(bridged)
   }
 }
+
+extension IntrusiveSet {
+  mutating func insert(contentsOf source: some Sequence<Element>) {
+    for element in source {
+      _ = insert(element)
+    }
+  }
+
+  init(insertContentsOf source: some Sequence<Element>, _ context: some Context) {
+    self.init(context)
+    insert(contentsOf: source)
+  }
+}

SwiftCompilerSources/Sources/SIL/Operand.swift

@@ -37,6 +37,13 @@ public struct Operand : CustomStringConvertible, NoReflectionChildren {
 
   public var index: Int { instruction.operands.getIndex(of: self) }
 
+  public var nextUse: Operand? {
+    if let bridgedNextUse = bridged.getNextUse().operand {
+      return Operand(bridged: bridgedNextUse)
+    }
+    return nil
+  }
+
   /// True if the operand is used to describe a type dependency, but it's not
   /// used as value.
   public var isTypeDependent: Bool { bridged.isTypeDependent() }

SwiftCompilerSources/Sources/SIL/Utilities/SequenceUtilities.swift

@@ -98,6 +98,8 @@ public extension CollectionLikeSequence {
     }
     return singleElement
   }
+
+  var first: Element? { first(where: { _ in true }) }
 }
 
 // Also make the lazy sequences a CollectionLikeSequence if the underlying sequence is one.