Subzero. ARM32. Improve constant lowering.

src/IceUtils.h

Index: src/IceUtils.h
diff --git a/src/IceUtils.h b/src/IceUtils.h
index 9387671fa21b5a54e6cf9d5b654dbd1b6b0fd89a..0080a11b87f051691f176f0cef4aa3dc6a8b4955 100644
--- a/src/IceUtils.h
+++ b/src/IceUtils.h
@@ -16,6 +16,7 @@
 #define SUBZERO_SRC_ICEUTILS_H
 
 #include <climits>
+#include <cmath> // std::signbit()
 
 namespace Ice {
 
@@ -117,6 +118,13 @@ public:
       return value;
     return (value >> shift) | (value << (32 - shift));
   }
+
+  /// Returns true if Val is +0.0. It requires T to be a floating point type.
+  template <typename T> static bool isPositiveZero(T Val) {
+    static_assert(std::is_floating_point<T>::value,
+                  "Input type must be floating point");
+    return Val == 0 && !std::signbit(Val);
+  }
 };
 
 } // end of namespace Ice