diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 0475814..0c12410 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1646,10 +1646,10 @@
     Flag = Chain.getValue(1);
   }
 
-  // The x86-64 ABI for returning structs by value requires that we copy
-  // the sret argument into %rax for the return. We saved the argument into
-  // a virtual register in the entry block, so now we copy the value out
-  // and into %rax.
+  // The x86-64 ABIs require that for returning structs by value we copy
+  // the sret argument into %rax/%eax (depending on ABI) for the return.
+  // We saved the argument into a virtual register in the entry block,
+  // so now we copy the value out and into %rax/%eax.
   if (Subtarget->is64Bit() &&
       DAG.getMachineFunction().getFunction()->hasStructRetAttr()) {
     MachineFunction &MF = DAG.getMachineFunction();
@@ -1659,11 +1659,12 @@
            "SRetReturnReg should have been set in LowerFormalArguments().");
     SDValue Val = DAG.getCopyFromReg(Chain, dl, Reg, getPointerTy());
 
-    Chain = DAG.getCopyToReg(Chain, dl, X86::RAX, Val, Flag);
+    unsigned RetValReg = Subtarget->isTarget64BitILP32() ? X86::EAX : X86::RAX;
+    Chain = DAG.getCopyToReg(Chain, dl, RetValReg, Val, Flag);
     Flag = Chain.getValue(1);
 
-    // RAX now acts like a return value.
-    MRI.addLiveOut(X86::RAX);
+    // RAX/EAX now acts like a return value.
+    MRI.addLiveOut(RetValReg);
   }
 
   RetOps[0] = Chain;  // Update chain.
@@ -2015,14 +2016,16 @@
     InVals.push_back(ArgValue);
   }
 
-  // The x86-64 ABI for returning structs by value requires that we copy
-  // the sret argument into %rax for the return. Save the argument into
-  // a virtual register so that we can access it from the return points.
+  // The x86-64 ABIs require that for returning structs by value we copy
+  // the sret argument into %rax/%eax (depending on ABI) for the return.
+  // Save the argument into a virtual register so that we can access it
+  // from the return points.
   if (Is64Bit && MF.getFunction()->hasStructRetAttr()) {
     X86MachineFunctionInfo *FuncInfo = MF.getInfo<X86MachineFunctionInfo>();
     unsigned Reg = FuncInfo->getSRetReturnReg();
     if (!Reg) {
-      Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i64));
+      MVT PtrTy = getPointerTy();
+      Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(PtrTy));
       FuncInfo->setSRetReturnReg(Reg);
     }
     SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), dl, Reg, InVals[0]);
diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index 58064b8..1dd1e41 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -177,20 +177,21 @@
 const TargetRegisterClass *
 X86RegisterInfo::getPointerRegClass(const MachineFunction &MF, unsigned Kind)
                                                                          const {
+  const X86Subtarget &Subtarget = TM.getSubtarget<X86Subtarget>();
   switch (Kind) {
   default: llvm_unreachable("Unexpected Kind in getPointerRegClass!");
   case 0: // Normal GPRs.
-    if (TM.getSubtarget<X86Subtarget>().is64Bit())
+    if (Subtarget.isTarget64BitLP64())
       return &X86::GR64RegClass;
     return &X86::GR32RegClass;
   case 1: // Normal GPRs except the stack pointer (for encoding reasons).
-    if (TM.getSubtarget<X86Subtarget>().is64Bit())
+    if (Subtarget.isTarget64BitLP64())
       return &X86::GR64_NOSPRegClass;
     return &X86::GR32_NOSPRegClass;
   case 2: // Available for tailcall (not callee-saved GPRs).
-    if (TM.getSubtarget<X86Subtarget>().isTargetWin64())
+    if (Subtarget.isTargetWin64())
       return &X86::GR64_TCW64RegClass;
-    if (TM.getSubtarget<X86Subtarget>().is64Bit())
+    else if (Subtarget.is64Bit())
       return &X86::GR64_TCRegClass;
 
     const Function *F = MF.getFunction();
diff --git a/lib/Target/X86/X86Subtarget.h b/lib/Target/X86/X86Subtarget.h
index 080f4cf..b325f62 100644
--- a/lib/Target/X86/X86Subtarget.h
+++ b/lib/Target/X86/X86Subtarget.h
@@ -194,7 +194,20 @@
   /// instruction.
   void AutoDetectSubtargetFeatures();
 
-  bool is64Bit() const { return In64BitMode; }
+  /// Is this x86_64? (disregarding specific ABI / programming model)
+  bool is64Bit() const {
+    return In64BitMode;
+  }
+
+  /// Is this x86_64 with the ILP32 programming model (x32 ABI)?
+  bool isTarget64BitILP32() const {
+    return In64BitMode && (TargetTriple.getEnvironment() == Triple::GNUX32);
+  }
+
+  /// Is this x86_64 with the LP64 programming model (standard AMD64, no x32)?
+  bool isTarget64BitLP64() const {
+    return In64BitMode && (TargetTriple.getEnvironment() != Triple::GNUX32);
+  }
 
   PICStyles::Style getPICStyle() const { return PICStyle; }
   void setPICStyle(PICStyles::Style Style)  { PICStyle = Style; }
diff --git a/lib/Target/X86/X86TargetMachine.cpp b/lib/Target/X86/X86TargetMachine.cpp
index 799f140..8aa58a2 100644
--- a/lib/Target/X86/X86TargetMachine.cpp
+++ b/lib/Target/X86/X86TargetMachine.cpp
@@ -59,8 +59,12 @@
                                          Reloc::Model RM, CodeModel::Model CM,
                                          CodeGenOpt::Level OL)
   : X86TargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, true),
-    DL("e-p:64:64-s:64-f64:64:64-i64:64:64-f80:128:128-f128:128:128-"
-               "n8:16:32:64-S128"),
+    // The x32 ABI dictates the ILP32 programming model for x64.
+    DL(getSubtargetImpl()->isTarget64BitILP32() ?
+        "e-p:32:32-s:64-f64:64:64-i64:64:64-f80:128:128-f128:128:128-"
+        "n8:16:32:64-S128" :
+        "e-p:64:64-s:64-f64:64:64-i64:64:64-f80:128:128-f128:128:128-"
+        "n8:16:32:64-S128"),
     InstrInfo(*this),
     TLInfo(*this),
     TSInfo(*this),
diff --git a/test/CodeGen/X86/x86-64-ptr-arg-simple.ll b/test/CodeGen/X86/x86-64-ptr-arg-simple.ll
new file mode 100644
index 0000000..6d46663
--- /dev/null
+++ b/test/CodeGen/X86/x86-64-ptr-arg-simple.ll
@@ -0,0 +1,29 @@
+; RUN: llc -mtriple=x86_64-pc-linux < %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnux32 < %s | FileCheck -check-prefix=X32ABI %s
+
+; %in is kept in %esi for both ABIs. But the pointer will be passed in %edi
+; for x32, not %rdi
+
+; CHECK: movl %esi, (%rdi)
+; X32ABI: movl %esi, (%edi)
+
+define void @foo(i32* nocapture %out, i32 %in) nounwind {
+entry:
+  store i32 %in, i32* %out, align 4
+  ret void
+}
+
+; CHECK: bar
+; CHECK: movl (%rsi), %eax
+
+; Similarly here, but for loading
+; X32ABI: bar
+; X32ABI: movl (%esi), %eax
+
+define void @bar(i32* nocapture %pOut, i32* nocapture %pIn) nounwind {
+entry:
+  %0 = load i32* %pIn, align 4
+  store i32 %0, i32* %pOut, align 4
+  ret void
+}
+
diff --git a/test/CodeGen/X86/x86-64-sret-return.ll b/test/CodeGen/X86/x86-64-sret-return.ll
index 7b5f189..bc8a543 100644
--- a/test/CodeGen/X86/x86-64-sret-return.ll
+++ b/test/CodeGen/X86/x86-64-sret-return.ll
@@ -1,11 +1,16 @@
-; RUN: llc < %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-apple-darwin8 < %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-pc-linux < %s | FileCheck %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnux32 < %s | FileCheck -check-prefix=X32ABI %s
 
-target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
-target triple = "x86_64-apple-darwin8"
-	%struct.foo = type { [4 x i64] }
+%struct.foo = type { [4 x i64] }
 
 ; CHECK: bar:
 ; CHECK: movq %rdi, %rax
+
+; For the x32 ABI, pointers are 32-bit so 32-bit instructions will be used
+; X32ABI: bar:
+; X32ABI: movl %edi, %eax
+
 define void @bar(%struct.foo* noalias sret  %agg.result, %struct.foo* %d) nounwind  {
 entry:
 	%d_addr = alloca %struct.foo*		; <%struct.foo**> [#uses=2]
@@ -57,6 +62,11 @@
 
 ; CHECK: foo:
 ; CHECK: movq %rdi, %rax
+
+; For the x32 ABI, pointers are 32-bit so 32-bit instructions will be used
+; X32ABI: foo:
+; X32ABI: movl %edi, %eax
+
 define void @foo({ i64 }* noalias nocapture sret %agg.result) nounwind {
   store { i64 } { i64 0 }, { i64 }* %agg.result
   ret void