Mark setjmp as "returns twice" and turn off SimpleCoalescing when called.

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.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the kinds of intrinsics supported by PNaCl.
@@ skipping 71 matching lines @@
     MemoryOrderAcquire,
     MemoryOrderRelease,
     MemoryOrderAcquireRelease,
     MemoryOrderSequentiallyConsistent,
     MemoryOrderNum // Invalid, keep last.
   };
 
   static bool VerifyMemoryOrder(uint64_t Order);
 
   // Basic attributes related to each intrinsic, that are relevant to
-  // code generation. We will want to have more attributes (e.g., Setjmp
-  // returns twice and which affects stack coloring) once the lowering
-  // cares about such attributes. Perhaps the attributes representation
-  // can be shared with general function calls, though most functions
-  // will be opaque.
+  // code generation. Perhaps the attributes representation can be shared
+  // with general function calls, but PNaCl currently strips all
+  // attributes from functions.
   struct IntrinsicInfo {
-    IntrinsicID ID : 31;
+    IntrinsicID ID : 30;
     bool HasSideEffects : 1;
+    bool ReturnsTwice : 1;
   };
 
   // The complete set of information about an intrinsic.
   struct FullIntrinsicInfo {
     struct IntrinsicInfo Info; // Information that CodeGen would care about.
 
     // Sanity check during parsing.
     Type Signature[kMaxIntrinsicParameters];
     uint8_t NumTypes;
   };
 
   // Find the information about a given intrinsic, based on function name.
   // The function name is expected to have the common "llvm." prefix
   // stripped. If found, returns a reference to a FullIntrinsicInfo entry
   // (valid for the lifetime of the map). Otherwise returns null.
   const FullIntrinsicInfo *find(const IceString &Name) const;
 
 private:
   // TODO(jvoung): May want to switch to something like LLVM's StringMap.
   typedef std::map<IceString, FullIntrinsicInfo> IntrinsicMap;
   IntrinsicMap map;
 
   Intrinsics(const Intrinsics &) LLVM_DELETED_FUNCTION;
   Intrinsics &operator=(const Intrinsics &) LLVM_DELETED_FUNCTION;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINTRINSICS_H