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

src/IceDefs.h

 //===- subzero/src/IceDefs.h - Common Subzero declarations ------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 207 matching lines @@
   IceV_Preds = 1 << 3,
   IceV_Succs = 1 << 4,
   IceV_Liveness = 1 << 5,
   IceV_RegOrigins = 1 << 6,
   IceV_LinearScan = 1 << 7,
   IceV_Frame = 1 << 8,
   IceV_AddrOpt = 1 << 9,
   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
 };
 typedef uint32_t VerboseMask;
 
 enum FileType {
   FT_Elf, /// ELF .o file
   FT_Asm, /// Assembly .s file
   FT_Iasm /// "Integrated assembler" .byte-style .s file
 };
@@ skipping 46 matching lines @@
   RPE_BasicBlockReordering,
   RPE_ConstantBlinding,
   RPE_FunctionReordering,
   RPE_GlobalVariableReordering,
   RPE_NopInsertion,
   RPE_PooledConstantReordering,
   RPE_RegAllocRandomization,
   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