Subzero: Fix over-aggressive bool folding.

src/IceIntrinsics.h

 //===- subzero/src/IceIntrinsics.h - List of Ice Intrinsics -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 88 matching lines @@
   // TODO(stichnot,kschimpf): Perform memory order validation in the bitcode
   // reader/parser, allowing LLVM and Subzero to share. See
   // https://code.google.com/p/nativeclient/issues/detail?id=4126 .
   static bool isMemoryOrderValid(IntrinsicID ID, uint64_t Order,
                                  uint64_t OrderOther = MemoryOrderInvalid);
 
   enum SideEffects { SideEffects_F = 0, SideEffects_T = 1 };
 
   enum ReturnsTwice { ReturnsTwice_F = 0, ReturnsTwice_T = 1 };
 
+  enum MemoryWrite { MemoryWrite_F = 0, MemoryWrite_T = 1 };
+
   /// Basic attributes related to each intrinsic, that are relevant to code
   /// generation. Perhaps the attributes representation can be shared with
   /// general function calls, but PNaCl currently strips all attributes from
   /// functions.
   struct IntrinsicInfo {
-    enum IntrinsicID ID : 30;
+    enum IntrinsicID ID : 29;
     enum SideEffects HasSideEffects : 1;
     enum ReturnsTwice ReturnsTwice : 1;
+    enum MemoryWrite IsMemoryWrite : 1;
   };
+  static_assert(sizeof(IntrinsicInfo) == 4, "IntrinsicInfo should be 32 bits");
 
   /// The types of validation values for FullIntrinsicInfo.validateCall.
   enum ValidateCallValue {
     IsValidCall,      /// Valid use of instrinsic call.
     BadReturnType,    /// Return type invalid for intrinsic.
     WrongNumOfArgs,   /// Wrong number of arguments for intrinsic.
     WrongCallArgType, /// Argument of wrong type.
   };
 
   /// The complete set of information about an intrinsic.
@@ skipping 37 matching lines @@
 
 private:
   // TODO(jvoung): May want to switch to something like LLVM's StringMap.
   using IntrinsicMap = std::unordered_map<GlobalString, FullIntrinsicInfo>;
   IntrinsicMap Map;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINTRINSICS_H