Lower signatures exposing struct registers to byval struct pointers

tools/opt/opt.cpp

 //===- opt.cpp - The LLVM Modular Optimizer -------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Optimizations may be specified an arbitrary number of times on the command
@@ skipping 373 matching lines @@
   initializeExpandSmallArgumentsPass(Registry);
   initializeExpandStructRegsPass(Registry);
   initializeExpandTlsConstantExprPass(Registry);
   initializeExpandTlsPass(Registry);
   initializeExpandVarArgsPass(Registry);
   initializeFixVectorLoadStoreAlignmentPass(Registry);
   initializeFlattenGlobalsPass(Registry);
   initializeGlobalCleanupPass(Registry);
   initializeGlobalizeConstantVectorsPass(Registry);
   initializeInsertDivideCheckPass(Registry);
+  initializeSimplifyStructRegSignaturesPass(Registry);
   initializePNaClABIVerifyFunctionsPass(Registry);
   initializePNaClABIVerifyModulePass(Registry);
   initializePNaClSjLjEHPass(Registry);
   initializePromoteI1OpsPass(Registry);
   initializePromoteIntegersPass(Registry);
   initializeRemoveAsmMemoryPass(Registry);
   initializeRenameEntryPointPass(Registry);
   initializeReplacePtrsWithIntsPass(Registry);
   initializeResolveAliasesPass(Registry);
   initializeResolvePNaClIntrinsicsPass(Registry);
@@ skipping 308 matching lines @@
 
   // Now that we have all of the passes ready, run them.
   Passes.run(*M.get());
 
   // Declare success.
   if (!NoOutput || PrintBreakpoints)
     Out->keep();
 
   return 0;
 }