Compute the loop nest depth of each CfgNode and weight Variables by it.

src/IceDefs.h

Index: src/IceDefs.h
diff --git a/src/IceDefs.h b/src/IceDefs.h
index 7ea34be88f1f40415bdd02346193629adfd3b3a0..353f22f1d4c26419e8fe45729d1e045c16860756 100644
--- a/src/IceDefs.h
+++ b/src/IceDefs.h
@@ -225,6 +225,7 @@ enum VerboseItem {
   IceV_Random = 1 << 10,
   IceV_Folding = 1 << 11,
   IceV_RMW = 1 << 12,
+  IceV_Loop = 1 << 13,
   IceV_All = ~IceV_None,
   IceV_Most = IceV_All & ~IceV_LinearScan
 };
@@ -291,6 +292,17 @@ enum RandomizationPassesEnum {
   RPE_num
 };
 
+inline bool add_overflow(uint32_t x, uint32_t y, uint32_t *sum) {

[Jim Stichnoth, 2015/09/03 21:35:09]

Maybe this should go in IceUtils.h?  Also, document it.

[ascull, 2015/09/03 22:47:12]

Done.

+  static_assert(std::is_same<uint32_t, unsigned>::value, "Need to match type");
+#if __has_builtin(__builtin_uadd_overflow)
+  return __builtin_uadd_overflow(x, y, sum);
+#else
+  uint64_t res = static_cast<uint64_t>(x) + y;
+  *sum = static_cast<uint32_t>(res);
+  return res > std::numeric_limits<uint32_t>;
+#endif
+}
+
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEDEFS_H