Index: include/llvm/IR/Module.h
===================================================================
--- include/llvm/IR/Module.h
+++ include/llvm/IR/Module.h
@@ -16,6 +16,7 @@
 #define LLVM_IR_MODULE_H
 
 #include "llvm-c/Types.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
@@ -840,6 +841,17 @@
   void setPIELevel(PIELevel::Level PL);
 /// @}
 
+  /// @}
+  /// @name Utility function for querying and setting code model
+  /// @{
+
+  /// Returns the code model (tiny, small, kernel, medium or large model)
+  Optional<CodeModel::Model> getCodeModel() const;
+
+  /// Set the code model (tiny, small, kernel, medium or large)
+  void setCodeModel(CodeModel::Model CL);
+  /// @}
+
   /// @name Utility functions for querying and setting PGO summary
   /// @{
 
Index: lib/IR/Module.cpp
===================================================================
--- lib/IR/Module.cpp
+++ lib/IR/Module.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/IR/Module.h"
 #include "SymbolTableListTraitsImpl.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
@@ -507,6 +508,24 @@
   addModuleFlag(ModFlagBehavior::Max, "PIE Level", PL);
 }
 
+Optional<CodeModel::Model> Module::getCodeModel() const {
+  auto *Val = cast_or_null<ConstantAsMetadata>(getModuleFlag("Code Model"));
+
+  if (!Val)
+    return None;
+
+  return static_cast<CodeModel::Model>(
+      cast<ConstantInt>(Val->getValue())->getZExtValue());
+}
+
+void Module::setCodeModel(CodeModel::Model CL) {
+  // Linking object files with different code models is undefined behavior
+  // because the compiler would have to generate additional code (to span
+  // longer jumps) if a larger code model is used with a smaller one.
+  // Therefore we will treat attempts to mix code models as an error.
+  addModuleFlag(ModFlagBehavior::Error, "Code Model", CL);
+}
+
 void Module::setProfileSummary(Metadata *M) {
   addModuleFlag(ModFlagBehavior::Error, "ProfileSummary", M);
 }
Index: lib/LTO/LTOBackend.cpp
===================================================================
--- lib/LTO/LTOBackend.cpp
+++ lib/LTO/LTOBackend.cpp
@@ -138,9 +138,15 @@
     RelocModel =
         M.getPICLevel() == PICLevel::NotPIC ? Reloc::Static : Reloc::PIC_;
 
+  Optional<CodeModel::Model> CodeModel;
+  if (Conf.CodeModel)
+    CodeModel = *Conf.CodeModel;
+  else if (M.getCodeModel())
+    CodeModel = M.getCodeModel();
+
   return std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(
       TheTriple, Conf.CPU, Features.getString(), Conf.Options, RelocModel,
-      Conf.CodeModel, Conf.CGOptLevel));
+      CodeModel, Conf.CGOptLevel));
 }
 
 static void runNewPMPasses(Config &Conf, Module &Mod, TargetMachine *TM,
Index: test/LTO/X86/Inputs/codemodel-3.ll
===================================================================
--- test/LTO/X86/Inputs/codemodel-3.ll
+++ test/LTO/X86/Inputs/codemodel-3.ll
@@ -0,0 +1,16 @@
+target triple = "x86_64-unknown-linux-gnu"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 1, !"Code Model", i32 1}
+
+%struct.rtx_def = type { i16, i16 }
+
+define void @bar(%struct.rtx_def* %a, i8 %b, i32 %c) {
+  call void  @llvm.memset.p0struct.rtx_def.i32(%struct.rtx_def* align 4 %a, i8 %b, i32 %c, i1 true)
+  ret void
+}
+
+declare void @llvm.memset.p0struct.rtx_def.i32(%struct.rtx_def*, i8, i32, i1)
Index: test/LTO/X86/codemodel-1.ll
===================================================================
--- test/LTO/X86/codemodel-1.ll
+++ test/LTO/X86/codemodel-1.ll
@@ -0,0 +1,20 @@
+; RUN: llvm-as %s -o %t.o
+; RUN: llvm-lto2 run -r %t.o,_start,px %t.o -o %t.s
+; RUN: llvm-objdump -d %t.s.0 | FileCheck %s --check-prefix=CHECK-SMALL
+
+target triple = "x86_64-unknown-linux-gnu"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 1, !"Code Model", i32 1}
+
+@data = internal constant [0 x i32] []
+
+define i32* @_start() nounwind readonly {
+entry:
+; CHECK-SMALL-LABEL:  _start:
+; CHECK-SMALL: leaq    (%rip), %rax
+    ret i32* getelementptr ([0 x i32], [0 x i32]* @data, i64 0, i64 0)
+}
Index: test/LTO/X86/codemodel-2.ll
===================================================================
--- test/LTO/X86/codemodel-2.ll
+++ test/LTO/X86/codemodel-2.ll
@@ -0,0 +1,20 @@
+; RUN: llvm-as %s -o %t.o
+; RUN: llvm-lto2 run -r %t.o,_start,px %t.o -o %t.s
+; RUN: llvm-objdump -d %t.s.0 | FileCheck %s --check-prefix=CHECK-LARGE
+
+target triple = "x86_64-unknown-linux-gnu"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 1, !"Code Model", i32 4}
+
+@data = internal constant [0 x i32] []
+
+define i32* @_start() nounwind readonly {
+entry:
+; CHECK-LARGE-LABEL: _start:
+; CHECK-LARGE: movabsq $0, %rax
+    ret i32* getelementptr ([0 x i32], [0 x i32]* @data, i64 0, i64 0)
+}
Index: test/LTO/X86/codemodel-3.ll
===================================================================
--- test/LTO/X86/codemodel-3.ll
+++ test/LTO/X86/codemodel-3.ll
@@ -0,0 +1,20 @@
+; RUN: llvm-as %s -o %t0.o
+; RUN: llvm-as < %p/Inputs/codemodel-3.ll > %t1.o
+; RUN: not llvm-lto2 run -r %t0.o,_start,px -r %t1.o,bar,px %t0.o %t1.o -o %t2.s 2>&1 | FileCheck %s 
+
+target triple = "x86_64-unknown-linux-gnu"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 1, !"Code Model", i32 4}
+
+@data = internal constant [0 x i32] []
+
+define i32* @_start() nounwind readonly {
+entry:
+    ret i32* getelementptr ([0 x i32], [0 x i32]* @data, i64 0, i64 0)
+}
+
+; CHECK: 'Code Model': IDs have conflicting values