Index: lib/Target/AMDGPU/AMDGPUISelLowering.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -4094,6 +4094,23 @@
       Known.Zero.setHighBits(Size - Subtarget->getWavefrontSizeLog2());
       break;
     }
+    case Intrinsic::amdgcn_workitem_id_x:
+    case Intrinsic::amdgcn_workitem_id_y:
+    case Intrinsic::amdgcn_workitem_id_z:
+    case Intrinsic::r600_read_tidig_x:
+    case Intrinsic::r600_read_tidig_y:
+    case Intrinsic::r600_read_tidig_z:
+    case Intrinsic::r600_read_local_size_x:
+    case Intrinsic::r600_read_local_size_y:
+    case Intrinsic::r600_read_local_size_z: {
+      unsigned Min, Max;
+
+      // Returns 1 more than the maximum value.
+      std::tie(Min, Max) = Subtarget->getWorkitemIDRange(
+        *DAG.getMachineFunction().getFunction(), IID);
+      Known.Zero.setHighBits(countLeadingZeros(Max - 1));
+      break;
+    }
     default:
       break;
     }
Index: lib/Target/AMDGPU/AMDGPUSubtarget.h
===================================================================
--- lib/Target/AMDGPU/AMDGPUSubtarget.h
+++ lib/Target/AMDGPU/AMDGPUSubtarget.h
@@ -627,6 +627,10 @@
   /// size, register usage, and/or lds usage.
   std::pair<unsigned, unsigned> getWavesPerEU(const Function &F) const;
 
+  /// Return min, max value range for a workitemid.* inrinsic call.
+  std::pair<unsigned, unsigned> getWorkitemIDRange(const Function &Kernel,
+                                                   unsigned FuncID) const;
+
   /// Creates value range metadata on an workitemid.* inrinsic call or load.
   bool makeLIDRangeMetadata(Instruction *I) const;
 };
Index: lib/Target/AMDGPU/AMDGPUSubtarget.cpp
===================================================================
--- lib/Target/AMDGPU/AMDGPUSubtarget.cpp
+++ lib/Target/AMDGPU/AMDGPUSubtarget.cpp
@@ -288,53 +288,49 @@
   return Requested;
 }
 
-bool AMDGPUSubtarget::makeLIDRangeMetadata(Instruction *I) const {
-  Function *Kernel = I->getParent()->getParent();
+std::pair<unsigned, unsigned> AMDGPUSubtarget::getWorkitemIDRange(
+  const Function &Kernel, unsigned FuncID) const {
   unsigned MinSize = 0;
-  unsigned MaxSize = getFlatWorkGroupSizes(*Kernel).second;
+  unsigned MaxSize = getFlatWorkGroupSizes(Kernel).second;
   bool IdQuery = false;
 
   // If reqd_work_group_size is present it narrows value down.
-  if (auto *CI = dyn_cast<CallInst>(I)) {
-    const Function *F = CI->getCalledFunction();
-    if (F) {
-      unsigned Dim = UINT_MAX;
-      switch (F->getIntrinsicID()) {
-      case Intrinsic::amdgcn_workitem_id_x:
-      case Intrinsic::r600_read_tidig_x:
-        IdQuery = true;
-        LLVM_FALLTHROUGH;
-      case Intrinsic::r600_read_local_size_x:
-        Dim = 0;
-        break;
-      case Intrinsic::amdgcn_workitem_id_y:
-      case Intrinsic::r600_read_tidig_y:
-        IdQuery = true;
-        LLVM_FALLTHROUGH;
-      case Intrinsic::r600_read_local_size_y:
-        Dim = 1;
-        break;
-      case Intrinsic::amdgcn_workitem_id_z:
-      case Intrinsic::r600_read_tidig_z:
-        IdQuery = true;
-        LLVM_FALLTHROUGH;
-      case Intrinsic::r600_read_local_size_z:
-        Dim = 2;
-        break;
-      default:
-        break;
-      }
-      if (Dim <= 3) {
-        if (auto Node = Kernel->getMetadata("reqd_work_group_size"))
-          if (Node->getNumOperands() == 3)
-            MinSize = MaxSize = mdconst::extract<ConstantInt>(
-                                  Node->getOperand(Dim))->getZExtValue();
-      }
-    }
+  unsigned Dim = UINT_MAX;
+  switch (FuncID) {
+  case Intrinsic::amdgcn_workitem_id_x:
+  case Intrinsic::r600_read_tidig_x:
+    IdQuery = true;
+    LLVM_FALLTHROUGH;
+  case Intrinsic::r600_read_local_size_x:
+    Dim = 0;
+    break;
+  case Intrinsic::amdgcn_workitem_id_y:
+  case Intrinsic::r600_read_tidig_y:
+    IdQuery = true;
+    LLVM_FALLTHROUGH;
+  case Intrinsic::r600_read_local_size_y:
+    Dim = 1;
+    break;
+  case Intrinsic::amdgcn_workitem_id_z:
+  case Intrinsic::r600_read_tidig_z:
+    IdQuery = true;
+    LLVM_FALLTHROUGH;
+  case Intrinsic::r600_read_local_size_z:
+    Dim = 2;
+    break;
+  default:
+    break;
+  }
+
+  if (Dim <= 3) {
+    if (auto Node = Kernel.getMetadata("reqd_work_group_size"))
+      if (Node->getNumOperands() == 3)
+        MinSize = MaxSize = mdconst::extract<ConstantInt>(
+          Node->getOperand(Dim))->getZExtValue();
   }
 
   if (!MaxSize)
-    return false;
+    return std::make_pair(MinSize, MaxSize);
 
   // Range metadata is [Lo, Hi). For ID query we need to pass max size
   // as Hi. For size query we need to pass Hi + 1.
@@ -343,6 +339,32 @@
   else
     ++MaxSize;
 
+  return std::make_pair(MinSize, MaxSize);
+}
+
+bool AMDGPUSubtarget::makeLIDRangeMetadata(Instruction *I) const {
+  unsigned MinSize = 0, MaxSize = 0;
+
+  unsigned IntrinID = 0;
+  if (auto *CI = dyn_cast<CallInst>(I)) {
+    if (const Function *F = CI->getCalledFunction()) {
+      IntrinID = F->getIntrinsicID();
+      std::tie(MinSize, MaxSize) = getWorkitemIDRange(
+        *I->getParent()->getParent(), IntrinID);
+    }
+  } else {
+    // Used when emitting loads from dispatch packet.
+    MaxSize = getFlatWorkGroupSizes(*I->getParent()->getParent()).second;
+
+    // Range metadata is [Lo, Hi). For ID query we need to pass max size
+    // as Hi. For size query we need to pass Hi + 1.
+    // This is a load, which is only used for sizes.
+    ++MaxSize;
+  }
+
+  if (!MaxSize)
+    return false;
+
   MDBuilder MDB(I->getContext());
   MDNode *MaxWorkGroupSizeRange = MDB.createRange(APInt(32, MinSize),
                                                   APInt(32, MaxSize));