Index: lib/Target/R600/R600ISelLowering.cpp
===================================================================
--- lib/Target/R600/R600ISelLowering.cpp
+++ lib/Target/R600/R600ISelLowering.cpp
@@ -1392,7 +1392,12 @@
 
     // The first 36 bytes of the input buffer contains information about
     // thread group and global sizes.
-    SDValue Arg = DAG.getExtLoad(ISD::SEXTLOAD, DL, VT, Chain,
+
+    // FIXME: This should really check the extload type, but the handling of
+    // extload vecto parameters seems to be broken.
+    //ISD::LoadExtType Ext = Ins[i].Flags.isSExt() ? ISD::SEXTLOAD : ISD::ZEXTLOAD;
+    ISD::LoadExtType Ext = ISD::SEXTLOAD;
+    SDValue Arg = DAG.getExtLoad(Ext, DL, VT, Chain,
                                  DAG.getConstant(36 + VA.getLocMemOffset(), MVT::i32),
                                  MachinePointerInfo(UndefValue::get(PtrTy)),
                                  MemVT, false, false, 4);
Index: lib/Target/R600/SIISelLowering.h
===================================================================
--- lib/Target/R600/SIISelLowering.h
+++ lib/Target/R600/SIISelLowering.h
@@ -22,7 +22,7 @@
 
 class SITargetLowering : public AMDGPUTargetLowering {
   SDValue LowerParameter(SelectionDAG &DAG, EVT VT, EVT MemVT, SDLoc DL,
-                         SDValue Chain, unsigned Offset) const;
+                         SDValue Chain, unsigned Offset, bool Signed) const;
   SDValue LowerSampleIntrinsic(unsigned Opcode, const SDValue &Op,
                                SelectionDAG &DAG) const;
   SDValue LowerLOAD(SDValue Op, SelectionDAG &DAG) const;
Index: lib/Target/R600/SIISelLowering.cpp
===================================================================
--- lib/Target/R600/SIISelLowering.cpp
+++ lib/Target/R600/SIISelLowering.cpp
@@ -224,7 +224,7 @@
 
 SDValue SITargetLowering::LowerParameter(SelectionDAG &DAG, EVT VT, EVT MemVT,
                                          SDLoc DL, SDValue Chain,
-                                         unsigned Offset) const {
+                                         unsigned Offset, bool Signed) const {
   MachineRegisterInfo &MRI = DAG.getMachineFunction().getRegInfo();
   PointerType *PtrTy = PointerType::get(VT.getTypeForEVT(*DAG.getContext()),
                                             AMDGPUAS::CONSTANT_ADDRESS);
@@ -232,7 +232,7 @@
                            MRI.getLiveInVirtReg(AMDGPU::SGPR0_SGPR1), MVT::i64);
   SDValue Ptr = DAG.getNode(ISD::ADD, DL, MVT::i64, BasePtr,
                                              DAG.getConstant(Offset, MVT::i64));
-  return DAG.getExtLoad(ISD::SEXTLOAD, DL, VT, Chain, Ptr,
+  return DAG.getExtLoad(Signed ? ISD::SEXTLOAD : ISD::ZEXTLOAD, DL, VT, Chain, Ptr,
                             MachinePointerInfo(UndefValue::get(PtrTy)), MemVT,
                             false, false, MemVT.getSizeInBits() >> 3);
 
@@ -340,7 +340,8 @@
       // The first 36 bytes of the input buffer contains information about
       // thread group and global sizes.
       SDValue Arg = LowerParameter(DAG, VT, MemVT,  DL, DAG.getRoot(),
-                                   36 + VA.getLocMemOffset());
+                                   36 + VA.getLocMemOffset(),
+                                   Ins[i].Flags.isSExt());
       InVals.push_back(Arg);
       continue;
     }
@@ -533,23 +534,23 @@
     switch (IntrinsicID) {
     default: return AMDGPUTargetLowering::LowerOperation(Op, DAG);
     case Intrinsic::r600_read_ngroups_x:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 0);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 0, false);
     case Intrinsic::r600_read_ngroups_y:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 4);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 4, false);
     case Intrinsic::r600_read_ngroups_z:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 8);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 8, false);
     case Intrinsic::r600_read_global_size_x:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 12);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 12, false);
     case Intrinsic::r600_read_global_size_y:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 16);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 16, false);
     case Intrinsic::r600_read_global_size_z:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 20);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 20, false);
     case Intrinsic::r600_read_local_size_x:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 24);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 24, false);
     case Intrinsic::r600_read_local_size_y:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 28);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 28, false);
     case Intrinsic::r600_read_local_size_z:
-      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 32);
+      return LowerParameter(DAG, VT, VT, DL, DAG.getEntryNode(), 32, false);
     case Intrinsic::r600_read_tgid_x:
       return CreateLiveInRegister(DAG, &AMDGPU::SReg_32RegClass,
                      AMDGPU::SReg_32RegClass.getRegister(NumUserSGPRs + 0), VT);