Index: lib/Driver/Driver.cpp
===================================================================
--- lib/Driver/Driver.cpp
+++ lib/Driver/Driver.cpp
@@ -1746,8 +1746,15 @@
   }
   case phases::Backend: {
     if (isUsingLTO()) {
-      types::ID Output =
-          Args.hasArg(options::OPT_S) ? types::TY_LTO_IR : types::TY_LTO_BC;
+      // -flto in conjunction with -S will still produce
+      // assembler, unless -emit-llvm is also specified.
+      // In that case, LLVM IR is produced instead.
+      types::ID Output;
+      if (Args.hasArg(options::OPT_S))
+        Output = (Args.hasArg(options::OPT_emit_llvm)) ? types::TY_LLVM_IR :
+            types::TY_PP_Asm;
+      else
+        Output = types::TY_LTO_BC;
       return C.MakeAction<BackendJobAction>(Input, Output);
     }
     if (Args.hasArg(options::OPT_emit_llvm)) {
Index: test/CodeGen/2009-10-20-GlobalDebug.c
===================================================================
--- test/CodeGen/2009-10-20-GlobalDebug.c
+++ test/CodeGen/2009-10-20-GlobalDebug.c
@@ -1,5 +1,6 @@
 // REQUIRES: x86-registered-target
-// RUN: %clang -target i386-apple-darwin10 -flto -S -g %s -o - | FileCheck %s
+// RUN: %clang -target i386-apple-darwin10 -flto -emit-llvm -S -g %s -o - |\
+// RUN:    FileCheck %s
 int global;
 int main() { 
   static int localstatic;
@@ -8,9 +9,9 @@
 
 // CHECK: !DIGlobalVariable(name: "localstatic"
 // CHECK-NOT:               linkageName:
-// CHECK-SAME:              line: 5,
+// CHECK-SAME:              line: 6,
 // CHECK-SAME:              variable: i32* @main.localstatic
 // CHECK: !DIGlobalVariable(name: "global"
 // CHECK-NOT:               linkageName:
-// CHECK-SAME:              line: 3,
+// CHECK-SAME:              line: 4,
 // CHECK-SAME:              variable: i32* @global
Index: test/CodeGen/emit-asm.c
===================================================================
--- test/CodeGen/emit-asm.c
+++ test/CodeGen/emit-asm.c
@@ -0,0 +1,15 @@
+// Make sure ASM is emitted instead of LLVM IR.
+// RUN: %clang_cc1 %s -S -flto -o - | FileCheck %s
+
+int foo(int goo) { return goo + 42; }
+
+// CHECK:   .section  __TEXT,__text,regular,pure_instructions
+// CHECK:   .macosx_version_min 10, 11
+// CHECK:   .globl  _foo
+// CHECK:   .p2align  4, 0x90
+// CHECK: _foo:
+// CHECK:   movl  %edi, -4(%rsp)
+// CHECK:   movl  -4(%rsp), %edi
+// CHECK:   addl  $42, %edi
+// CHECK:   movl  %edi, %eax
+// CHECK:   retq
Index: test/CodeGenCXX/cxx-apple-kext.cpp
===================================================================
--- test/CodeGenCXX/cxx-apple-kext.cpp
+++ test/CodeGenCXX/cxx-apple-kext.cpp
@@ -1,7 +1,7 @@
-// RUN: %clangxx -target x86_64-apple-darwin10 %s -flto -S -o - |\
+// RUN: %clangxx -target x86_64-apple-darwin10 %s -flto -S -emit-llvm -o - |\
 // RUN:   FileCheck --check-prefix=CHECK-NO-KEXT %s
-// RUN: %clangxx -target x86_64-apple-darwin10 %s -fapple-kext -flto -S -o - |\
-// RUN:   FileCheck --check-prefix=CHECK-KEXT %s
+// RUN: %clangxx -target x86_64-apple-darwin10 %s -fapple-kext -flto -S \
+// RUN:   -emit-llvm -o - | FileCheck --check-prefix=CHECK-KEXT %s
 
 // CHECK-NO-KEXT-NOT: _GLOBAL__D_a
 // CHECK-NO-KEXT: @is_hosted = global
Index: test/Driver/darwin-iphone-defaults.m
===================================================================
--- test/Driver/darwin-iphone-defaults.m
+++ test/Driver/darwin-iphone-defaults.m
@@ -1,4 +1,4 @@
-// RUN: %clang -target i386-apple-darwin9 -miphoneos-version-min=3.0 -arch armv7 -stdlib=platform -flto -S -o - %s | FileCheck %s
+// RUN: %clang -target i386-apple-darwin9 -miphoneos-version-min=3.0 -arch armv7 -stdlib=platform -flto -S -emit-llvm -o - %s | FileCheck %s
 
 // CHECK: @f0() [[F0:#[0-9]+]]
 // CHECK: @__f0_block_invoke
Index: test/Driver/darwin-objc-gc.m
===================================================================
--- test/Driver/darwin-objc-gc.m
+++ test/Driver/darwin-objc-gc.m
@@ -1,6 +1,6 @@
 // Check that we warn, but accept, -fobjc-gc for iPhone OS.
 
-// RUN: %clang -target i386-apple-darwin9 -miphoneos-version-min=3.0 -stdlib=platform -fobjc-gc -flto -S -o %t %s 2> %t.err
+// RUN: %clang -target i386-apple-darwin9 -miphoneos-version-min=3.0 -stdlib=platform -fobjc-gc -flto -S -emit-llvm -o %t %s 2> %t.err
 // RUN: FileCheck --check-prefix=IPHONE_OBJC_GC_LL %s < %t 
 // RUN: FileCheck --check-prefix=IPHONE_OBJC_GC_STDERR %s < %t.err