Subzero: Count lookups of each constant value in the constant pool.

src/IceCfg.h

Index: src/IceCfg.h
diff --git a/src/IceCfg.h b/src/IceCfg.h
index 8cfe4748558a7e3c67cc1c5047d57f40cf574dfd..cfb49565daed7f980ed4cfd04b38681716f671d1 100644
--- a/src/IceCfg.h
+++ b/src/IceCfg.h
@@ -41,7 +41,7 @@ public:
   uint32_t getSequenceNumber() const { return SequenceNumber; }
 
   static constexpr VerboseMask defaultVerboseMask() {
-    return IceV_All & ~IceV_Status & ~IceV_AvailableRegs;
+    return (IceV_NO_PER_PASS_DUMP_BEYOND << 1) - 1;
   }
   /// Returns true if any of the specified options in the verbose mask are set.
   /// If the argument is omitted, it checks if any verbose options at all are