[NFC] Convenience for setting a singleton explosion

Author: rjmccall

lib/IRGen/IRGenSIL.cpp

@@ -200,6 +200,11 @@ class LoweredValue {
   }
   ExternalUnion<Kind, Members, getMemberIndexForKind> Storage;
 
+  explicit LoweredValue(llvm::Value *singletonValue)
+      : kind(Kind::SingletonExplosion) {
+    Storage.emplace<SingletonExplosion>(kind, singletonValue);
+  }
+
 public:
 
   /// Create an address value without a stack restore point.
@@ -275,6 +280,10 @@ class LoweredValue {
     Storage.moveConstruct(kind, std::move(lv.Storage));
   }
 
+  static LoweredValue forSingletonExplosion(llvm::Value *value) {
+    return LoweredValue(value);
+  }
+
   LoweredValue &operator=(LoweredValue &&lv) {
     Storage.moveAssign(kind, lv.kind, std::move(lv.Storage));
     kind = lv.kind;
@@ -491,6 +500,10 @@ class IRGenSILFunction :
     assert(v->getType().isObject() && "explosion for address value?!");
     setLoweredValue(v, LoweredValue(e));
   }
+  void setLoweredSingletonExplosion(SILValue v, llvm::Value *value) {
+    assert(v->getType().isObject() && "explosion for address value?!");
+    setLoweredValue(v, LoweredValue::forSingletonExplosion(value));
+  }
 
   void setCorrespondingLoweredValues(SILInstructionResultArray results,
                                      Explosion &allValues) {