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

src/IceCompileServer.cpp

 //===- subzero/src/IceCompileServer.cpp - Compile server ------------------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 222 matching lines @@
     std::thread CompileThread([this, &ExtraFlags, &InputStream]() {
       Ctx->initParserThread();
       getCompiler().run(ExtraFlags, *Ctx.get(), std::move(InputStream));
     });
     CompileThread.join();
   } else {
     getCompiler().run(ExtraFlags, *Ctx.get(), std::move(InputStream));
   }
   transferErrorCode(getReturnValue(
       ExtraFlags, static_cast<ErrorCodes>(Ctx->getErrorStatus()->value())));
+  Ctx->dumpConstantLookupCounts();
 }
 
 } // end of namespace Ice