diff --git a/llvm/lib/Target/AMDGPU/AMDGPULowerKernelAttributes.cpp b/llvm/lib/Target/AMDGPU/AMDGPULowerKernelAttributes.cpp
--- a/llvm/lib/Target/AMDGPU/AMDGPULowerKernelAttributes.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPULowerKernelAttributes.cpp
@@ -102,17 +102,21 @@
       continue;
 
     int64_t Offset = 0;
-    BitCastInst *BCI = dyn_cast<BitCastInst>(U);
-    if (!BCI) {
+    auto *Load = dyn_cast<LoadInst>(U); // Load from ImplicitArgPtr/DispatchPtr?
+    auto *BCI = dyn_cast<BitCastInst>(U);
+    if (!Load && !BCI) {
       if (GetPointerBaseWithConstantOffset(U, Offset, DL) != CI)
         continue;
+      Load = dyn_cast<LoadInst>(*U->user_begin()); // Load from GEP?
       BCI = dyn_cast<BitCastInst>(*U->user_begin());
     }
 
-    if (!BCI || !BCI->hasOneUse())
-      continue;
+    if (BCI) {
+      if (!BCI->hasOneUse())
+        continue;
+      Load = dyn_cast<LoadInst>(*BCI->user_begin()); // Load from BCI?
+    }
 
-    auto *Load = dyn_cast<LoadInst>(*BCI->user_begin());
     if (!Load || !Load->isSimple())
       continue;
 
diff --git a/llvm/test/CodeGen/AMDGPU/implicit-arg-v5-opt-opaque-ptr.ll b/llvm/test/CodeGen/AMDGPU/implicit-arg-v5-opt-opaque-ptr.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/implicit-arg-v5-opt-opaque-ptr.ll
@@ -0,0 +1,76 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -mtriple=amdgcn-amd-amdhsa --amdhsa-code-object-version=5 -S -opaque-pointers -passes=amdgpu-lower-kernel-attributes,instcombine %s | FileCheck -enable-var-scope -check-prefix=GCN %s
+
+; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn
+define amdgpu_kernel void @get_local_size_x_opaque_pointer(i16 addrspace(1)* %out) #0 {
+; GCN-LABEL: @get_local_size_x_opaque_pointer(
+; GCN-NEXT:    [[IMPLICITARG_PTR:%.*]] = tail call ptr addrspace(4) @llvm.amdgcn.implicitarg.ptr()
+; GCN-NEXT:    [[GEP_LOCAL_SIZE:%.*]] = getelementptr inbounds i8, ptr addrspace(4) [[IMPLICITARG_PTR]], i64 12
+; GCN-NEXT:    [[LOCAL_SIZE:%.*]] = load i16, ptr addrspace(4) [[GEP_LOCAL_SIZE]], align 4
+; GCN-NEXT:    store i16 [[LOCAL_SIZE]], ptr addrspace(1) [[OUT:%.*]], align 2
+; GCN-NEXT:    ret void
+;
+  %group.id = tail call i32 @llvm.amdgcn.workgroup.id.x()
+  %implicitarg.ptr = tail call ptr addrspace(4) @llvm.amdgcn.implicitarg.ptr()
+  %block.count.x = load i32, ptr addrspace(4) %implicitarg.ptr, align 4
+  %cmp.id.count = icmp ult i32 %group.id, %block.count.x
+  %local.size.offset = select i1 %cmp.id.count, i64 12, i64 18
+  %gep.local.size = getelementptr inbounds i8, ptr addrspace(4) %implicitarg.ptr, i64 %local.size.offset
+  %local.size = load i16, ptr addrspace(4) %gep.local.size, align 2
+  store i16 %local.size, i16 addrspace(1)* %out
+  ret void
+}
+
+; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn
+define amdgpu_kernel void @get_local_size_y_opaque_pointer(i16 addrspace(1)* %out) #0 {
+; GCN-LABEL: @get_local_size_y_opaque_pointer(
+; GCN-NEXT:    [[IMPLICITARG_PTR:%.*]] = tail call ptr addrspace(4) @llvm.amdgcn.implicitarg.ptr()
+; GCN-NEXT:    [[GEP_LOCAL_SIZE:%.*]] = getelementptr inbounds i8, ptr addrspace(4) [[IMPLICITARG_PTR]], i64 14
+; GCN-NEXT:    [[LOCAL_SIZE:%.*]] = load i16, ptr addrspace(4) [[GEP_LOCAL_SIZE]], align 2
+; GCN-NEXT:    store i16 [[LOCAL_SIZE]], ptr addrspace(1) [[OUT:%.*]], align 2
+; GCN-NEXT:    ret void
+;
+  %group.id = tail call i32 @llvm.amdgcn.workgroup.id.y()
+  %implicitarg.ptr = tail call ptr addrspace(4) @llvm.amdgcn.implicitarg.ptr()
+  %gep.block.count.y = getelementptr inbounds i8, ptr addrspace(4) %implicitarg.ptr, i64 4
+  %block.count.y = load i32, ptr addrspace(4) %gep.block.count.y, align 4
+  %cmp.id.count = icmp ult i32 %group.id, %block.count.y
+  %local.size.offset = select i1 %cmp.id.count, i64 14, i64 20
+  %gep.local.size = getelementptr inbounds i8, ptr addrspace(4) %implicitarg.ptr, i64 %local.size.offset
+  %local.size = load i16, ptr addrspace(4) %gep.local.size, align 2
+  store i16 %local.size, i16 addrspace(1)* %out
+  ret void
+}
+
+; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn
+define amdgpu_kernel void @get_local_size_z_opaque_pointer(i16 addrspace(1)* %out) #0 {
+; GCN-LABEL: @get_local_size_z_opaque_pointer(
+; GCN-NEXT:    [[IMPLICITARG_PTR:%.*]] = tail call ptr addrspace(4) @llvm.amdgcn.implicitarg.ptr()
+; GCN-NEXT:    [[GEP_LOCAL_SIZE:%.*]] = getelementptr inbounds i8, ptr addrspace(4) [[IMPLICITARG_PTR]], i64 16
+; GCN-NEXT:    [[LOCAL_SIZE:%.*]] = load i16, ptr addrspace(4) [[GEP_LOCAL_SIZE]], align 4
+; GCN-NEXT:    store i16 [[LOCAL_SIZE]], ptr addrspace(1) [[OUT:%.*]], align 2
+; GCN-NEXT:    ret void
+;
+  %group.id = tail call i32 @llvm.amdgcn.workgroup.id.z()
+  %implicitarg.ptr = tail call ptr addrspace(4) @llvm.amdgcn.implicitarg.ptr()
+  %gep.block.count.z = getelementptr inbounds i8, ptr addrspace(4) %implicitarg.ptr, i64 8
+  %block.count.z = load i32, ptr addrspace(4) %gep.block.count.z, align 4
+  %cmp.id.count = icmp ult i32 %group.id, %block.count.z
+  %local.size.offset = select i1 %cmp.id.count, i64 16, i64 22
+  %gep.local.size = getelementptr inbounds i8, ptr addrspace(4) %implicitarg.ptr, i64 %local.size.offset
+  %local.size = load i16, ptr addrspace(4) %gep.local.size, align 2
+  store i16 %local.size, i16 addrspace(1)* %out
+  ret void
+}
+
+declare ptr addrspace(4) @llvm.amdgcn.implicitarg.ptr() #1
+declare i32 @llvm.amdgcn.workgroup.id.x() #1
+declare i32 @llvm.amdgcn.workgroup.id.y() #1
+declare i32 @llvm.amdgcn.workgroup.id.z() #1
+
+!llvm.module.flags = !{!1}
+
+attributes #0 = { nounwind "uniform-work-group-size"="true" }
+attributes #1 = { nounwind readnone speculatable }
+!0 = !{i32 8, i32 16, i32 2}
+!1 = !{i32 1, !"amdgpu_code_object_version", i32 500}