Lower signatures exposing struct registers to byval struct pointers

tools/opt/opt.cpp

Index: tools/opt/opt.cpp
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index d1efd2501799ffeab9e1ce6e8216033bc9a63fe4..0746339362e1f98ba75b61c710b6a086a79692f7 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -391,6 +391,7 @@ int main(int argc, char **argv) {
   initializeGlobalCleanupPass(Registry);
   initializeGlobalizeConstantVectorsPass(Registry);
   initializeInsertDivideCheckPass(Registry);
+  initializeSimplifyStructRegSignaturesPass(Registry);
   initializePNaClABIVerifyFunctionsPass(Registry);
   initializePNaClABIVerifyModulePass(Registry);
   initializePNaClSjLjEHPass(Registry);