diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index 261b3c4fa4aa573b501faf04cb2390623e9f5834..ed9bb5e77d65f2158768037a038c4650cc935fb8 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -225,6 +225,9 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
     CI.setFileManager(&AST->getFileManager());
     CI.setSourceManager(&AST->getSourceManager());
     CI.setPreprocessor(AST->getPreprocessorPtr());
+    Preprocessor &PP = CI.getPreprocessor();
+    PP.getBuiltinInfo().initializeBuiltins(PP.getIdentifierTable(),
+                                           PP.getLangOpts());
     CI.setASTContext(&AST->getASTContext());
 
     setCurrentInput(Input, std::move(AST));
diff --git a/test/Modules/Inputs/codegen/bar.h b/test/Modules/Inputs/codegen-opt/bar.h
similarity index 100%
rename from test/Modules/Inputs/codegen/bar.h
rename to test/Modules/Inputs/codegen-opt/bar.h
diff --git a/test/Modules/Inputs/codegen/bar.modulemap b/test/Modules/Inputs/codegen-opt/bar.modulemap
similarity index 100%
rename from test/Modules/Inputs/codegen/bar.modulemap
rename to test/Modules/Inputs/codegen-opt/bar.modulemap
diff --git a/test/Modules/Inputs/codegen-opt/foo.h b/test/Modules/Inputs/codegen-opt/foo.h
new file mode 100644
index 0000000000000000000000000000000000000000..b3a7af7c9d9bc650a03d8f434c7ea51ec2fb804f
--- /dev/null
+++ b/test/Modules/Inputs/codegen-opt/foo.h
@@ -0,0 +1,10 @@
+void f1(int &);
+static void f2() {}
+inline void foo() {
+  static int i;
+  f1(i);
+  f2();
+}
+inline void foo2() {
+}
+void foo_ext() {}
diff --git a/test/Modules/Inputs/codegen-opt/foo.modulemap b/test/Modules/Inputs/codegen-opt/foo.modulemap
new file mode 100644
index 0000000000000000000000000000000000000000..2e095d2794c3448b44a9990e8aac19e576ff6835
--- /dev/null
+++ b/test/Modules/Inputs/codegen-opt/foo.modulemap
@@ -0,0 +1 @@
+module foo { header "foo.h" }
diff --git a/test/Modules/Inputs/codegen/use.cpp b/test/Modules/Inputs/codegen-opt/use.cpp
similarity index 100%
rename from test/Modules/Inputs/codegen/use.cpp
rename to test/Modules/Inputs/codegen-opt/use.cpp
diff --git a/test/Modules/Inputs/codegen/foo.h b/test/Modules/Inputs/codegen/foo.h
index b3a7af7c9d9bc650a03d8f434c7ea51ec2fb804f..3fcab7185731b9aa07d258f948573a2cf95ea496 100644
--- a/test/Modules/Inputs/codegen/foo.h
+++ b/test/Modules/Inputs/codegen/foo.h
@@ -1,10 +1,4 @@
-void f1(int &);
-static void f2() {}
-inline void foo() {
-  static int i;
-  f1(i);
-  f2();
+inline void f1(const char* fmt, ...) {
+  __builtin_va_list args;
+  __builtin_va_start(args, fmt);
 }
-inline void foo2() {
-}
-void foo_ext() {}
diff --git a/test/Modules/codegen-opt.test b/test/Modules/codegen-opt.test
new file mode 100644
index 0000000000000000000000000000000000000000..2f4997a7c73f076ee764bb1c027426f7d7d22c14
--- /dev/null
+++ b/test/Modules/codegen-opt.test
@@ -0,0 +1,65 @@
+RUN: rm -rf %t
+REQUIRES: x86-registered-target
+
+RUN: %clang_cc1 -triple=x86_64-linux-gnu -fmodules-codegen -x c++ -fmodules -emit-module -fmodule-name=foo %S/Inputs/codegen-opt/foo.modulemap -o %t/foo.pcm
+RUN: %clang_cc1 -triple=x86_64-linux-gnu -fmodules-codegen -x c++ -fmodules -emit-module -fmodule-name=bar %S/Inputs/codegen-opt/bar.modulemap -o %t/bar.pcm -fmodule-file=%t/foo.pcm
+
+RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - %t/foo.pcm | FileCheck --check-prefix=FOO %s
+RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - %t/bar.pcm -fmodule-file=%t/foo.pcm | FileCheck --check-prefix=BAR-CMN --check-prefix=BAR %s
+RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -fmodules -fmodule-file=%t/foo.pcm -fmodule-file=%t/bar.pcm %S/Inputs/codegen-opt/use.cpp | FileCheck --check-prefix=USE-CMN --check-prefix=USE %s
+
+RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes %t/foo.pcm | FileCheck --check-prefix=FOO %s
+RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes %t/bar.pcm -fmodule-file=%t/foo.pcm | FileCheck --check-prefix=BAR-CMN --check-prefix=BAR-OPT %s
+RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes -fmodules -fmodule-file=%t/foo.pcm -fmodule-file=%t/bar.pcm %S/Inputs/codegen-opt/use.cpp | FileCheck --check-prefix=USE-CMN --check-prefix=USE-OPT %s
+
+FOO-NOT: comdat
+FOO: $_Z3foov = comdat any
+FOO: $_Z4foo2v = comdat any
+FOO: $_ZZ3foovE1i = comdat any
+FOO: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat
+FOO-NOT: {{comdat|define|declare}}
+FOO: define void @_Z7foo_extv()
+FOO-NOT: {{define|declare}}
+FOO: define weak_odr void @_Z3foov() #{{[0-9]+}} comdat
+FOO-NOT: {{define|declare}}
+FOO: declare void @_Z2f1Ri(i32*
+FOO-NOT: {{define|declare}}
+
+FIXME: this internal function should be weak_odr, comdat, and with a new mangling
+FOO: define internal void @_ZL2f2v() #{{[0-9]+}}
+FOO-NOT: {{define|declare}}
+
+FOO: define weak_odr void @_Z4foo2v() #{{[0-9]+}} comdat
+FOO-NOT: {{define|declare}}
+
+
+BAR-CMN-NOT: comdat
+BAR-CMN: $_Z3barv = comdat any
+BAR-OPT: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat
+BAR-CMN-NOT: {{comdat|define|declare}}
+BAR-CMN: define weak_odr void @_Z3barv() #{{[0-9]+}} comdat
+BAR-CMN-NOT: {{define|declare}}
+BAR: declare void @_Z3foov()
+Include all the available_externally definitions required for bar (foo -> f2)
+BAR-OPT: define available_externally void @_Z3foov()
+BAR-CMN-NOT: {{define|declare}}
+BAR-OPT: declare void @_Z2f1Ri(i32*
+BAR-OPT-NOT: {{define|declare}}
+BAR-OPT: define available_externally void @_ZL2f2v()
+BAR-OPT-NOT: {{define|declare}}
+
+
+USE-OPT: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat
+USE-CMN-NOT: {{comdat|define|declare}}
+USE-CMN: define i32 @main()
+USE-CMN-NOT: {{define|declare}}
+USE: declare void @_Z3barv()
+Include all the available_externally definitions required for main (bar -> foo -> f2)
+USE-OPT: define available_externally void @_Z3barv()
+USE-CMN-NOT: {{define|declare}}
+USE-OPT: define available_externally void @_Z3foov()
+USE-OPT-NOT: {{define|declare}}
+USE-OPT: declare void @_Z2f1Ri(i32*
+USE-OPT-NOT: {{define|declare}}
+USE-OPT: define available_externally void @_ZL2f2v()
+USE-OPT-NOT: {{define|declare}}
diff --git a/test/Modules/codegen.test b/test/Modules/codegen.test
index bc3c14357aa14a8a5f5301a1ecbee07a895e7a4c..f1823d55bafc94c5eeb84b1560081604c15e4ed2 100644
--- a/test/Modules/codegen.test
+++ b/test/Modules/codegen.test
@@ -2,64 +2,9 @@ RUN: rm -rf %t
 REQUIRES: x86-registered-target
 
 RUN: %clang_cc1 -triple=x86_64-linux-gnu -fmodules-codegen -x c++ -fmodules -emit-module -fmodule-name=foo %S/Inputs/codegen/foo.modulemap -o %t/foo.pcm
-RUN: %clang_cc1 -triple=x86_64-linux-gnu -fmodules-codegen -x c++ -fmodules -emit-module -fmodule-name=bar %S/Inputs/codegen/bar.modulemap -o %t/bar.pcm -fmodule-file=%t/foo.pcm
 
-RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - %t/foo.pcm | FileCheck --check-prefix=FOO %s
-RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - %t/bar.pcm -fmodule-file=%t/foo.pcm | FileCheck --check-prefix=BAR-CMN --check-prefix=BAR %s
-RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -fmodules -fmodule-file=%t/foo.pcm -fmodule-file=%t/bar.pcm %S/Inputs/codegen/use.cpp | FileCheck --check-prefix=USE-CMN --check-prefix=USE %s
+RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - %t/foo.pcm | FileCheck %s
 
-RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes %t/foo.pcm | FileCheck --check-prefix=FOO %s
-RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes %t/bar.pcm -fmodule-file=%t/foo.pcm | FileCheck --check-prefix=BAR-CMN --check-prefix=BAR-OPT %s
-RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -o - -O2 -disable-llvm-passes -fmodules -fmodule-file=%t/foo.pcm -fmodule-file=%t/bar.pcm %S/Inputs/codegen/use.cpp | FileCheck --check-prefix=USE-CMN --check-prefix=USE-OPT %s
-
-FOO-NOT: comdat
-FOO: $_Z3foov = comdat any
-FOO: $_Z4foo2v = comdat any
-FOO: $_ZZ3foovE1i = comdat any
-FOO: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat
-FOO-NOT: {{comdat|define|declare}}
-FOO: define void @_Z7foo_extv()
-FOO-NOT: {{define|declare}}
-FOO: define weak_odr void @_Z3foov() #{{[0-9]+}} comdat
-FOO-NOT: {{define|declare}}
-FOO: declare void @_Z2f1Ri(i32*
-FOO-NOT: {{define|declare}}
-
-FIXME: this internal function should be weak_odr, comdat, and with a new mangling
-FOO: define internal void @_ZL2f2v() #{{[0-9]+}}
-FOO-NOT: {{define|declare}}
-
-FOO: define weak_odr void @_Z4foo2v() #{{[0-9]+}} comdat
-FOO-NOT: {{define|declare}}
-
-
-BAR-CMN-NOT: comdat
-BAR-CMN: $_Z3barv = comdat any
-BAR-OPT: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat
-BAR-CMN-NOT: {{comdat|define|declare}}
-BAR-CMN: define weak_odr void @_Z3barv() #{{[0-9]+}} comdat
-BAR-CMN-NOT: {{define|declare}}
-BAR: declare void @_Z3foov()
-Include all the available_externally definitions required for bar (foo -> f2)
-BAR-OPT: define available_externally void @_Z3foov()
-BAR-CMN-NOT: {{define|declare}}
-BAR-OPT: declare void @_Z2f1Ri(i32*
-BAR-OPT-NOT: {{define|declare}}
-BAR-OPT: define available_externally void @_ZL2f2v()
-BAR-OPT-NOT: {{define|declare}}
-
-
-USE-OPT: @_ZZ3foovE1i = linkonce_odr global i32 0, comdat
-USE-CMN-NOT: {{comdat|define|declare}}
-USE-CMN: define i32 @main()
-USE-CMN-NOT: {{define|declare}}
-USE: declare void @_Z3barv()
-Include all the available_externally definitions required for main (bar -> foo -> f2)
-USE-OPT: define available_externally void @_Z3barv()
-USE-CMN-NOT: {{define|declare}}
-USE-OPT: define available_externally void @_Z3foov()
-USE-OPT-NOT: {{define|declare}}
-USE-OPT: declare void @_Z2f1Ri(i32*
-USE-OPT-NOT: {{define|declare}}
-USE-OPT: define available_externally void @_ZL2f2v()
-USE-OPT-NOT: {{define|declare}}
+CHECK: $_Z2f1PKcz = comdat any
+CHECK: define weak_odr void @_Z2f1PKcz(i8* %fmt, ...) #{{[0-9]+}} comdat
+CHECK:   call void @llvm.va_start(i8* %{{[a-zA-Z0-9]*}})