Added "isExact" field to FloatingLiteral. This flag indicates whether or not

the APFloat representing the parsed literal can represent the literal value
exactly.  This is useful when performing various semantic checks on the code,
and issuing appropriate warnings to users.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@44423 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 15 insertions, 5 deletions

diff --git a/AST/StmtSerialization.cpp b/AST/StmtSerialization.cpp
index 3134f8859c..120b68e5c5 100644
--- a/AST/StmtSerialization.cpp
+++ b/AST/StmtSerialization.cpp
@@ -507,14 +507,16 @@ DoStmt* DoStmt::CreateImpl(Deserializer& D) {
 void FloatingLiteral::EmitImpl(Serializer& S) const {
   S.Emit(Loc);
   S.Emit(getType());
+  S.EmitBool(isExact());
   S.Emit(Value);
 }
 
 FloatingLiteral* FloatingLiteral::CreateImpl(Deserializer& D) {
   SourceLocation Loc = SourceLocation::ReadVal(D);
   QualType t = QualType::ReadVal(D);
+  bool isExact = D.ReadBool();
   llvm::APFloat Val = llvm::APFloat::ReadVal(D);
-  FloatingLiteral* expr = new FloatingLiteral(Val,t,Loc);
+  FloatingLiteral* expr = new FloatingLiteral(Val,&isExact,t,Loc);
   return expr;
 }
 
diff --git a/Sema/SemaExpr.cpp b/Sema/SemaExpr.cpp
index 14302aab08..336dca716e 100644
--- a/Sema/SemaExpr.cpp
+++ b/Sema/SemaExpr.cpp
@@ -188,8 +188,12 @@ Action::ExprResult Sema::ActOnNumericConstant(const Token &Tok) {
       Context.Target.getDoubleInfo(Size, Align, Format, Tok.getLocation());
     }
     
-    Res = new FloatingLiteral(Literal.GetFloatValue(*Format), Ty,
-                              Tok.getLocation());
+    // isExact will be set by GetFloatValue().
+    bool isExact = false;
+    
+    Res = new FloatingLiteral(Literal.GetFloatValue(*Format,&isExact), &isExact, 
+                              Ty, Tok.getLocation());
+    
   } else if (!Literal.isIntegerLiteral()) {
     return ExprResult(true);
   } else {
diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index 7ee3afc6b7..91cee5ef00 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -240,12 +240,16 @@ public:
 
 class FloatingLiteral : public Expr {
   llvm::APFloat Value;
+  bool IsExact : 1;
   SourceLocation Loc;
 public:
-  FloatingLiteral(const llvm::APFloat &V, QualType Type, SourceLocation L)
-    : Expr(FloatingLiteralClass, Type), Value(V), Loc(L) {} 
+  FloatingLiteral(const llvm::APFloat &V, bool* isexact, 
+                  QualType Type, SourceLocation L)
+    : Expr(FloatingLiteralClass, Type), Value(V), IsExact(*isexact), Loc(L) {} 
 
   const llvm::APFloat &getValue() const { return Value; }
+  
+  bool isExact() const { return IsExact; }
 
   /// getValueAsDouble - This returns the value as an inaccurate double.  Note
   /// that this may cause loss of precision, but is useful for debugging dumps