[CodeGen][NFC] Update comments in CGExprConstant.cpp.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@353571 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 8dbfab8345aa5959b732d15b207f70466f53f203..62cc12c7def50505d503d0f18ce7e0448f23f1e4 100644 (file)
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -700,10 +700,12 @@ EmitArrayConstant(CodeGenModule &CGM, const ConstantArrayType *DestType,
   return llvm::ConstantStruct::get(SType, Elements);
 }
 
-/// This class only needs to handle two cases:
-/// 1) Literals (this is used by APValue emission to emit literals).
-/// 2) Arrays, structs and unions (outside C++11 mode, we don't currently
-///    constant fold these types).
+// This class only needs to handle arrays, structs and unions. Outside C++11
+// mode, we don't currently constant fold those types.  All other types are
+// handled by constant folding.
+//
+// Constant folding is currently missing support for a few features supported
+// here: CK_ToUnion, CK_ReinterpretMemberPointer, and DesignatedInitUpdateExpr.
 class ConstExprEmitter :
   public StmtVisitor<ConstExprEmitter, llvm::Constant*, QualType> {
   CodeGenModule &CGM;
@@ -1076,6 +1078,7 @@ public:
   }
 
   llvm::Constant *VisitStringLiteral(StringLiteral *E, QualType T) {
+    // This is a string literal initializing an array in an initializer.
     return CGM.GetConstantArrayFromStringLiteral(E);
   }
 
@@ -1649,7 +1652,7 @@ private:
 llvm::Constant *ConstantLValueEmitter::tryEmit() {
   const APValue::LValueBase &base = Value.getLValueBase();
 
-  // Otherwise, the destination type should be a pointer or reference
+  // The destination type should be a pointer or reference
   // type, but it might also be a cast thereof.
   //
   // FIXME: the chain of casts required should be reflected in the APValue.