Index: clang-tools-extra/clang-tidy/readability/StaticAccessedThroughInstanceCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/readability/StaticAccessedThroughInstanceCheck.cpp
+++ clang-tools-extra/clang-tidy/readability/StaticAccessedThroughInstanceCheck.cpp
@@ -9,6 +9,7 @@
 #include "StaticAccessedThroughInstanceCheck.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "llvm/ADT/StringRef.h"
 
 using namespace clang::ast_matchers;
 
@@ -54,7 +55,7 @@
 
   const Expr *BaseExpr = MemberExpression->getBase();
 
-  // Do not warn for overlaoded -> operators.
+  // Do not warn for overloaded -> operators.
   if (isa<CXXOperatorCallExpr>(BaseExpr))
     return;
 
@@ -70,6 +71,10 @@
   std::string BaseTypeName =
       BaseType.getAsString(PrintingPolicyWithSupressedTag);
 
+  // Do not warn for CUDA built-in variables.
+  if (StringRef(BaseTypeName).startswith("__cuda_builtin_"))
+    return;
+
   SourceLocation MemberExprStartLoc = MemberExpression->getBeginLoc();
   auto Diag =
       diag(MemberExprStartLoc, "static member accessed through instance");
Index: clang-tools-extra/test/clang-tidy/checkers/Inputs/readability-static-accessed-through-instance/__clang_cuda_builtin_vars.h
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/Inputs/readability-static-accessed-through-instance/__clang_cuda_builtin_vars.h
@@ -0,0 +1,36 @@
+//===--- __clang_cuda_builtin_vars.h - Stub header for tests ----*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ___CLANG_CUDA_BUILTIN_VARS_H_
+#define ___CLANG_CUDA_BUILTIN_VARS_H_
+
+#define __CUDA_DEVICE_BUILTIN(FIELD) \
+  static unsigned int FIELD;
+
+struct __cuda_builtin_threadIdx_t {
+  __CUDA_DEVICE_BUILTIN(x);
+};
+
+struct __cuda_builtin_blockIdx_t {
+  __CUDA_DEVICE_BUILTIN(x);
+};
+
+struct __cuda_builtin_blockDim_t {
+  __CUDA_DEVICE_BUILTIN(x);
+};
+
+struct __cuda_builtin_gridDim_t {
+  __CUDA_DEVICE_BUILTIN(x);
+};
+
+__cuda_builtin_threadIdx_t threadIdx;
+__cuda_builtin_blockIdx_t blockIdx;
+__cuda_builtin_blockDim_t blockDim;
+__cuda_builtin_gridDim_t gridDim;
+
+#endif // ___CLANG_CUDA_BUILTIN_VARS_H_
Index: clang-tools-extra/test/clang-tidy/checkers/readability-static-accessed-through-instance.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/readability-static-accessed-through-instance.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/readability-static-accessed-through-instance.cpp
@@ -1,4 +1,5 @@
-// RUN: %check_clang_tidy %s readability-static-accessed-through-instance %t
+// RUN: %check_clang_tidy %s readability-static-accessed-through-instance %t -- -- -isystem %S/Inputs/readability-static-accessed-through-instance
+#include <__clang_cuda_builtin_vars.h>
 
 struct C {
   static void foo();
@@ -248,3 +249,17 @@
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: static member
   // CHECK-FIXES: {{^}}  Outer::S::I;{{$}}
 }
+
+// https://bugs.llvm.org/show_bug.cgi?id=48758
+namespace Bugzilla_48758 {
+
+unsigned int x1 = threadIdx.x;
+// CHECK-MESSAGES-NOT: :[[@LINE-1]]:10: warning: static member
+unsigned int x2 = blockIdx.x;
+// CHECK-MESSAGES-NOT: :[[@LINE-1]]:10: warning: static member
+unsigned int x3 = blockDim.x;
+// CHECK-MESSAGES-NOT: :[[@LINE-1]]:10: warning: static member
+unsigned int x4 = gridDim.x;
+// CHECK-MESSAGES-NOT: :[[@LINE-1]]:10: warning: static member
+
+} // namespace Bugzilla_48758