Index: llvm/trunk/include/llvm/Object/ELFObjectFile.h
===================================================================
--- llvm/trunk/include/llvm/Object/ELFObjectFile.h
+++ llvm/trunk/include/llvm/Object/ELFObjectFile.h
@@ -825,6 +825,8 @@
     switch (EF.getHeader()->e_machine) {
     case ELF::EM_386:
       return "ELF32-i386";
+    case ELF::EM_IAMCU:
+      return "ELF32-iamcu";
     case ELF::EM_X86_64:
       return "ELF32-x86-64";
     case ELF::EM_ARM:
@@ -873,6 +875,7 @@
   bool IsLittleEndian = ELFT::TargetEndianness == support::little;
   switch (EF.getHeader()->e_machine) {
   case ELF::EM_386:
+  case ELF::EM_IAMCU:
     return Triple::x86;
   case ELF::EM_X86_64:
     return Triple::x86_64;
Index: llvm/trunk/lib/Object/ELF.cpp
===================================================================
--- llvm/trunk/lib/Object/ELF.cpp
+++ llvm/trunk/lib/Object/ELF.cpp
@@ -26,6 +26,7 @@
     }
     break;
   case ELF::EM_386:
+  case ELF::EM_IAMCU:
     switch (Type) {
 #include "llvm/Support/ELFRelocs/i386.def"
     default:
Index: llvm/trunk/lib/Object/ELFYAML.cpp
===================================================================
--- llvm/trunk/lib/Object/ELFYAML.cpp
+++ llvm/trunk/lib/Object/ELFYAML.cpp
@@ -486,6 +486,7 @@
 #include "llvm/Support/ELFRelocs/Hexagon.def"
     break;
   case ELF::EM_386:
+  case ELF::EM_IAMCU:
 #include "llvm/Support/ELFRelocs/i386.def"
     break;
   case ELF::EM_AARCH64:
Index: llvm/trunk/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
+++ llvm/trunk/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
@@ -359,6 +359,17 @@
   }
 };
 
+class ELFX86_IAMCUAsmBackend : public ELFX86AsmBackend {
+public:
+  ELFX86_IAMCUAsmBackend(const Target &T, uint8_t OSABI, StringRef CPU)
+      : ELFX86AsmBackend(T, OSABI, CPU) {}
+
+  MCObjectWriter *createObjectWriter(raw_pwrite_stream &OS) const override {
+    return createX86ELFObjectWriter(OS, /*IsELF64*/ false, OSABI,
+                                    ELF::EM_IAMCU);
+  }
+};
+
 class ELFX86_64AsmBackend : public ELFX86AsmBackend {
 public:
   ELFX86_64AsmBackend(const Target &T, uint8_t OSABI, StringRef CPU)
@@ -780,6 +791,10 @@
     return new WindowsX86AsmBackend(T, false, CPU);
 
   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TheTriple.getOS());
+
+  if (TheTriple.isOSIAMCU())
+    return new ELFX86_IAMCUAsmBackend(T, OSABI, CPU);
+
   return new ELFX86_32AsmBackend(T, OSABI, CPU);
 }
 
Index: llvm/trunk/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
+++ llvm/trunk/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp
@@ -32,9 +32,11 @@
 
 X86ELFObjectWriter::X86ELFObjectWriter(bool IsELF64, uint8_t OSABI,
                                        uint16_t EMachine)
-  : MCELFObjectTargetWriter(IsELF64, OSABI, EMachine,
-                            // Only i386 uses Rel instead of RelA.
-                            /*HasRelocationAddend*/ EMachine != ELF::EM_386) {}
+    : MCELFObjectTargetWriter(IsELF64, OSABI, EMachine,
+                              // Only i386 and IAMCU use Rel instead of RelA.
+                              /*HasRelocationAddend*/
+                              (EMachine != ELF::EM_386) &&
+                                  (EMachine != ELF::EM_IAMCU)) {}
 
 X86ELFObjectWriter::~X86ELFObjectWriter()
 {}
@@ -246,7 +248,8 @@
   if (getEMachine() == ELF::EM_X86_64)
     return getRelocType64(Modifier, Type, IsPCRel);
 
-  assert(getEMachine() == ELF::EM_386 && "Unsupported ELF machine type.");
+  assert((getEMachine() == ELF::EM_386 || getEMachine() == ELF::EM_IAMCU) &&
+         "Unsupported ELF machine type.");
   return getRelocType32(Modifier, getType32(Type), IsPCRel);
 }
 
Index: llvm/trunk/test/MC/ELF/relocation-386.s
===================================================================
--- llvm/trunk/test/MC/ELF/relocation-386.s
+++ llvm/trunk/test/MC/ELF/relocation-386.s
@@ -1,8 +1,11 @@
-// RUN: llvm-mc -filetype=obj -triple i386-pc-linux-gnu %s -o - | llvm-readobj -r  | FileCheck  %s
+// RUN: llvm-mc -filetype=obj -triple i386-pc-linux-gnu %s -o - | llvm-readobj -r  | FileCheck  %s --check-prefix=CHECK --check-prefix=I386 
+// RUN: llvm-mc -filetype=obj -triple i386-pc-elfiamcu %s -o - | llvm-readobj -r  | FileCheck  %s --check-prefix=CHECK --check-prefix=IAMCU
 
 // Test that we produce the correct relocation types and that the relocations
 // correctly point to the section or the symbol.
 
+// IAMCU: Format: ELF32-iamcu
+// I386: Format: ELF32-i386
 // CHECK:      Relocations [
 // CHECK-NEXT:   Section {{.*}} .rel.text {
 // CHECK-NEXT:     0x2          R_386_GOTOFF     .Lfoo 0x0
Index: llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp
===================================================================
--- llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp
+++ llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp
@@ -477,6 +477,7 @@
     break;
   }
   case ELF::EM_386:
+  case ELF::EM_IAMCU:
   case ELF::EM_ARM:
   case ELF::EM_HEXAGON:
   case ELF::EM_MIPS: