5 files changed, 50 insertions, 6 deletions
diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index 0a457d6b97a..474b796ea63 100644
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -3269,7 +3269,7 @@ private:
 
   // This is only meaningful for operations on floating point types and 0
   // otherwise.
-  unsigned FPFeatures : 2;
+  unsigned FPFeatures : 3;
   SourceLocation OpLoc;
 
   enum { LHS, RHS, END_EXPR };
@@ -3448,6 +3448,12 @@ public:
     return FPOptions(FPFeatures).allowFPContractWithinStatement();
   }
 
+  // Get the FENV_ACCESS status of this operator. Only meaningful for
+  // operations on floating point types.
+  bool isFEnvAccessOn() const {
+    return FPOptions(FPFeatures).allowFEnvAccess();
+  }
+
 protected:
   BinaryOperator(Expr *lhs, Expr *rhs, Opcode opc, QualType ResTy,
                  ExprValueKind VK, ExprObjectKind OK,
diff --git a/clang/include/clang/Basic/LangOptions.h b/clang/include/clang/Basic/LangOptions.h
index a1396f84352..a7a5105fdfb 100644
--- a/clang/include/clang/Basic/LangOptions.h
+++ b/clang/include/clang/Basic/LangOptions.h
@@ -137,6 +137,14 @@ public:
     FPC_Fast
   };
 
+  // TODO: merge FEnvAccessModeKind and FPContractModeKind
+  enum FEnvAccessModeKind {
+    FEA_Off,
+
+    FEA_On
+  };
+
+
 public:
   /// Set of enabled sanitizers.
   SanitizerSet Sanitize;
@@ -262,14 +270,19 @@ public:
 /// Floating point control options
 class FPOptions {
 public:
-  FPOptions() : fp_contract(LangOptions::FPC_Off) {}
+  FPOptions() : fp_contract(LangOptions::FPC_Off), 
+                fenv_access(LangOptions::FEA_Off) {}
 
   // Used for serializing.
   explicit FPOptions(unsigned I)
-      : fp_contract(static_cast<LangOptions::FPContractModeKind>(I)) {}
+      : fp_contract(static_cast<LangOptions::FPContractModeKind>(I & 3)),
+        fenv_access(static_cast<LangOptions::FEnvAccessModeKind>((I >> 2) & 1))
+        {}
 
   explicit FPOptions(const LangOptions &LangOpts)
-      : fp_contract(LangOpts.getDefaultFPContractMode()) {}
+      : fp_contract(LangOpts.getDefaultFPContractMode()),
+        fenv_access(LangOptions::FEA_Off) {}
+  // FIXME: Use getDefaultFEnvAccessMode() when available.
 
   bool allowFPContractWithinStatement() const {
     return fp_contract == LangOptions::FPC_On;
@@ -289,12 +302,24 @@ public:
 
   void setDisallowFPContract() { fp_contract = LangOptions::FPC_Off; }
 
+  bool allowFEnvAccess() const {
+    return fenv_access == LangOptions::FEA_On;
+  }
+
+  void setAllowFEnvAccess() {
+    fenv_access = LangOptions::FEA_On;
+  }
+
+  void setDisallowFEnvAccess() { fenv_access = LangOptions::FEA_Off; }
+
   /// Used to serialize this.
-  unsigned getInt() const { return fp_contract; }
+  unsigned getInt() const { return fp_contract | (fenv_access << 2); }
 
 private:
-  /// Adjust BinaryOperator::FPFeatures to match the bit-field size of this.
+  /// Adjust BinaryOperator::FPFeatures to match the total bit-field size 
+  /// of these two.
   unsigned fp_contract : 2;
+  unsigned fenv_access : 1;
 };
 
 /// Describes the kind of translation unit being processed.
diff --git a/clang/include/clang/Basic/TokenKinds.def b/clang/include/clang/Basic/TokenKinds.def
index 30cb022f1cb..caea67adba4 100644
--- a/clang/include/clang/Basic/TokenKinds.def
+++ b/clang/include/clang/Basic/TokenKinds.def
@@ -780,6 +780,11 @@ ANNOTATION(pragma_redefine_extname)
 // handles them.
 ANNOTATION(pragma_fp_contract)
 
+// Annotation for #pragma STDC FENV_ACCESS
+// The lexer produces these so that they only take effect when the parser
+// handles them.
+ANNOTATION(pragma_fenv_access)
+
 // Annotation for #pragma pointers_to_members...
 // The lexer produces these so that they only take effect when the parser
 // handles them.
diff --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 1d6849cd5b4..32874ee44ff 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -670,6 +670,10 @@ private:
   void HandlePragmaFPContract();
 
   /// Handle the annotation token produced for
+  /// #pragma STDC FENV_ACCESS...
+  void HandlePragmaFEnvAccess();
+
+  /// \brief Handle the annotation token produced for
   /// #pragma clang fp ...
   void HandlePragmaFP();
 
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index b3d1c96bdfc..aa6e4b7cfe8 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -8434,6 +8434,10 @@ public:
   /// \#pragma clang fp contract
   void ActOnPragmaFPContract(LangOptions::FPContractModeKind FPC);
 
+  /// ActOnPragmaFenvAccess - Called on well formed
+  /// \#pragma STDC FENV_ACCESS
+  void ActOnPragmaFEnvAccess(LangOptions::FEnvAccessModeKind FPC);
+
   /// AddAlignmentAttributesForRecord - Adds any needed alignment attributes to
   /// a the record decl, to handle '\#pragma pack' and '\#pragma options align'.
   void AddAlignmentAttributesForRecord(RecordDecl *RD);