diff --git a/clang/docs/analyzer/checkers.rst b/clang/docs/analyzer/checkers.rst
--- a/clang/docs/analyzer/checkers.rst
+++ b/clang/docs/analyzer/checkers.rst
@@ -66,7 +66,20 @@
 
 core.NullDereference (C, C++, ObjC)
 """""""""""""""""""""""""""""""""""
-Check for dereferences of null pointers.
+Check for dereferences of null pointers. 
+
+This checker specifically does
+not report null pointer dereferences for x86 and x86-64 targets when the
+address space is 256 (x86 GS Segment), 257 (x86 FS Segment), or 258 (x86 SS
+segment). See `X86/X86-64 Language Extensions
+<https://clang.llvm.org/docs/LanguageExtensions.html#memory-references-to-specified-segments>`__
+for reference.
+
+The ``SuppressAddressSpaces`` option suppresses 
+warnings for null dereferences of all pointers with address spaces. You can
+disable this behavior with the option
+``-analyzer-config core.NullDereference:SuppressAddressSpaces=false``.
+*Defaults to true*.
 
 .. code-block:: objc
 
diff --git a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
--- a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -191,6 +191,13 @@
 
 def DereferenceChecker : Checker<"NullDereference">,
   HelpText<"Check for dereferences of null pointers">,
+  CheckerOptions<[
+    CmdLineOption<Boolean,
+                  "SuppressAddressSpaces",
+                  "Suppresses warning when pointer dereferences an address space",
+                  "true",
+                  Released>
+  ]>,
   Documentation<HasDocumentation>;
 
 def NonNullParamChecker : Checker<"NonNullParamChecker">,
diff --git a/clang/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
--- a/clang/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/DereferenceChecker.cpp
@@ -11,9 +11,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
 #include "clang/AST/ExprObjC.h"
 #include "clang/AST/ExprOpenMP.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
 #include "clang/StaticAnalyzer/Core/Checker.h"
 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
@@ -39,6 +40,8 @@
   void reportBug(DerefKind K, ProgramStateRef State, const Stmt *S,
                  CheckerContext &C) const;
 
+  bool suppressReport(CheckerContext &C, const Expr *E) const;
+
 public:
   void checkLocation(SVal location, bool isLoad, const Stmt* S,
                      CheckerContext &C) const;
@@ -49,6 +52,8 @@
                              const Expr *Ex, const ProgramState *state,
                              const LocationContext *LCtx,
                              bool loadedFrom = false);
+
+  bool SuppressAddressSpaces = false;
 };
 } // end anonymous namespace
 
@@ -109,9 +114,35 @@
   return E;
 }
 
-static bool suppressReport(const Expr *E) {
-  // Do not report dereferences on memory in non-default address spaces.
-  return E->getType().hasAddressSpace();
+bool DereferenceChecker::suppressReport(CheckerContext &C,
+                                        const Expr *E) const {
+  // Do not report dereferences on memory that use address space #256, #257,
+  // and #258. Those address spaces are used when dereferencing address spaces
+  // relative to the GS, FS, and SS segments on x86/x86-64 targets.
+  // Dereferencing a null pointer in these address spaces is not defined
+  // as an error. All other null dereferences in other address spaces
+  // are defined as an error unless explicitly defined.
+  // See https://clang.llvm.org/docs/LanguageExtensions.html, the section
+  // "X86/X86-64 Language Extensions"
+
+  QualType Ty = E->getType();
+  if (!Ty.hasAddressSpace())
+    return false;
+  if (SuppressAddressSpaces)
+    return true;
+
+  const llvm::Triple::ArchType Arch =
+      C.getASTContext().getTargetInfo().getTriple().getArch();
+
+  if ((Arch == llvm::Triple::x86) || (Arch == llvm::Triple::x86_64)) {
+    switch (toTargetAddressSpace(E->getType().getAddressSpace())) {
+    case 256:
+    case 257:
+    case 258:
+      return true;
+    }
+  }
+  return false;
 }
 
 static bool isDeclRefExprToReference(const Expr *E) {
@@ -209,7 +240,7 @@
   // Check for dereference of an undefined value.
   if (l.isUndef()) {
     const Expr *DerefExpr = getDereferenceExpr(S);
-    if (!suppressReport(DerefExpr))
+    if (!suppressReport(C, DerefExpr))
       reportBug(DerefKind::UndefinedPointerValue, C.getState(), DerefExpr, C);
     return;
   }
@@ -230,7 +261,7 @@
       // We know that 'location' can only be null.  This is what
       // we call an "explicit" null dereference.
       const Expr *expr = getDereferenceExpr(S);
-      if (!suppressReport(expr)) {
+      if (!suppressReport(C, expr)) {
         reportBug(DerefKind::NullPointer, nullState, expr, C);
         return;
       }
@@ -272,7 +303,7 @@
   if (StNull) {
     if (!StNonNull) {
       const Expr *expr = getDereferenceExpr(S, /*IsBind=*/true);
-      if (!suppressReport(expr)) {
+      if (!suppressReport(C, expr)) {
         reportBug(DerefKind::NullPointer, StNull, expr, C);
         return;
       }
@@ -308,7 +339,9 @@
 }
 
 void ento::registerDereferenceChecker(CheckerManager &mgr) {
-  mgr.registerChecker<DereferenceChecker>();
+  auto *Chk = mgr.registerChecker<DereferenceChecker>();
+  Chk->SuppressAddressSpaces = mgr.getAnalyzerOptions().getCheckerBooleanOption(
+      mgr.getCurrentCheckerName(), "SuppressAddressSpaces");
 }
 
 bool ento::shouldRegisterDereferenceChecker(const CheckerManager &mgr) {
diff --git a/clang/test/Analysis/analyzer-config.c b/clang/test/Analysis/analyzer-config.c
--- a/clang/test/Analysis/analyzer-config.c
+++ b/clang/test/Analysis/analyzer-config.c
@@ -41,6 +41,7 @@
 // CHECK-NEXT: core.CallAndMessage:NilReceiver = true
 // CHECK-NEXT: core.CallAndMessage:ParameterCount = true
 // CHECK-NEXT: core.CallAndMessage:UndefReceiver = true
+// CHECK-NEXT: core.NullDereference:SuppressAddressSpaces = true
 // CHECK-NEXT: cplusplus.Move:WarnOn = KnownsAndLocals
 // CHECK-NEXT: cplusplus.SmartPtrModeling:ModelSmartPtrDereference = false
 // CHECK-NEXT: crosscheck-with-z3 = false
diff --git a/clang/test/Analysis/cast-value-notes.cpp b/clang/test/Analysis/cast-value-notes.cpp
--- a/clang/test/Analysis/cast-value-notes.cpp
+++ b/clang/test/Analysis/cast-value-notes.cpp
@@ -1,10 +1,44 @@
-// RUN: %clang_analyze_cc1 -std=c++14 \
-// RUN:  -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
-// RUN:  -analyzer-output=text -verify -DDEFAULT_TRIPLE %s 2>&1 | FileCheck %s -check-prefix=DEFAULT-CHECK
+// RUN: %clang_analyze_cc1 -std=c++14 -triple amdgcn-unknown-unknown \
+// RUN: -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN: -analyzer-output=text -verify -DX86 -DSUPPRESSED %s 2>&1 | FileCheck %s -check-prefix=X86-CHECK
+//
+// RUN: %clang_analyze_cc1 -std=c++14 -triple amdgcn-unknown-unknown \
+// RUN: -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN:  -analyzer-config core.NullDereference:SuppressAddressSpaces=false\
+// RUN:  -analyzer-output=text -verify -DX86 -DNOT_SUPPRESSED %s 2>&1 | FileCheck %s -check-prefix=X86-CHECK
 //
 // RUN: %clang_analyze_cc1 -std=c++14 -triple amdgcn-unknown-unknown \
 // RUN: -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
-// RUN: -analyzer-output=text -verify -DAMDGCN_TRIPLE %s 2>&1 | FileCheck %s -check-prefix=AMDGCN-CHECK
+// RUN:  -analyzer-config core.NullDereference:SuppressAddressSpaces=true\
+// RUN:  -analyzer-output=text -verify -DX86 -DSUPPRESSED %s 2>&1 | FileCheck %s -check-prefix=X86-CHECK
+//
+// RUN: %clang_analyze_cc1 -std=c++14 -triple x86_64-unknown-unknown \
+// RUN:  -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN:  -analyzer-output=text -verify -DX86 -DSUPPRESSED %s 2>&1 | FileCheck %s --check-prefix=X86-CHECK
+//
+// RUN: %clang_analyze_cc1 -std=c++14 -triple x86_64-unknown-unknown \
+// RUN:  -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN:  -analyzer-config core.NullDereference:SuppressAddressSpaces=true\
+// RUN:  -analyzer-output=text -verify -DX86 -DSUPPRESSED %s 2>&1 | FileCheck %s --check-prefix=X86-CHECK-SUPPRESSED
+//
+// RUN: %clang_analyze_cc1 -std=c++14 -triple x86_64-unknown-unknown \
+// RUN:  -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN:  -analyzer-config core.NullDereference:SuppressAddressSpaces=false\
+// RUN:  -analyzer-output=text -verify -DX86 -DNOT_SUPPRESSED %s 2>&1 | FileCheck %s --check-prefix=X86-CHECK
+//
+// RUN: %clang_analyze_cc1 -std=c++14 -triple mips-unknown-unknown \
+// RUN: -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN: -analyzer-output=text -verify -DMIPS %s 2>&1
+//
+// RUN: %clang_analyze_cc1 -std=c++14 -triple mips-unknown-unknown \
+// RUN: -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN: -analyzer-config core.NullDereference:SuppressAddressSpaces=false\
+// RUN: -analyzer-output=text -verify -DMIPS %s 2>&1
+//
+// RUN: %clang_analyze_cc1 -std=c++14 -triple mips-unknown-unknown \
+// RUN: -analyzer-checker=core,apiModeling.llvm.CastValue,debug.ExprInspection\
+// RUN: -analyzer-config core.NullDereference:SuppressAddressSpaces=true\
+// RUN: -analyzer-output=text -verify -DMIPS_SUPPRESSED %s
 
 #include "Inputs/llvm.h"
 
@@ -36,27 +70,51 @@
 
 void clang_analyzer_printState();
 
-#if defined(DEFAULT_TRIPLE)
+#if defined(X86)
 void evalReferences(const Shape &S) {
   const auto &C = dyn_cast<Circle>(S);
   // expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
   // expected-note@-2 {{Dereference of null pointer}}
   // expected-warning@-3 {{Dereference of null pointer}}
   clang_analyzer_printState();
-  // DEFAULT-CHECK: "dynamic_types": [
-  // DEFAULT-CHECK-NEXT: { "region": "SymRegion{reg_$0<const struct clang::Shape & S>}", "dyn_type": "const class clang::Circle &", "sub_classable": true }
+  // XX86-CHECK:      "dynamic_types": [
+  // XX86-CHECK-NEXT:   { "region": "SymRegion{reg_$0<const struct clang::Shape & S>}", "dyn_type": "const class clang::Circle &", "sub_classable": true }
   (void)C;
 }
-#elif defined(AMDGCN_TRIPLE)
-void evalReferences(const Shape &S) {
+#if defined(SUPPRESSED)
+void evalReferences_addrspace(const Shape &S) {
   const auto &C = dyn_cast<DEVICE Circle>(S);
   clang_analyzer_printState();
-  // AMDGCN-CHECK: "dynamic_types": [
-  // AMDGCN-CHECK-NEXT: { "region": "SymRegion{reg_$0<const struct clang::Shape & S>}", "dyn_type": "const __attribute__((address_space(3))) class clang::Circle &", "sub_classable": true }
+  // X86-CHECK-SUPPRESSED: "dynamic_types": [
+  // X86-CHECK-SUPPRESSED-NEXT: { "region": "SymRegion{reg_$0<const struct clang::Shape & S>}", "dyn_type": "const __attribute__((address_space(3))) class clang::Circle &", "sub_classable": true }
   (void)C;
 }
-#else
-#error Target must be specified, and must be pinned
+#endif
+#if defined(NOT_SUPPRESSED)
+void evalReferences_addrspace(const Shape &S) {
+  const auto &C = dyn_cast<DEVICE Circle>(S);
+  // expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
+  // expected-note@-2 {{Dereference of null pointer}}
+  // expected-warning@-3 {{Dereference of null pointer}}
+  clang_analyzer_printState();
+  // X86-CHECK: "dynamic_types": [
+  // X86-CHECK-NEXT: { "region": "SymRegion{reg_$0<const struct clang::Shape & S>}", "dyn_type": "const __attribute__((address_space(3))) class clang::Circle &", "sub_classable": true }
+  (void)C;
+}
+#endif
+#elif defined(MIPS)
+void evalReferences(const Shape &S) {
+  const auto &C = dyn_cast<Circle>(S);
+  // expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
+  // expected-note@-2 {{Dereference of null pointer}}
+  // expected-warning@-3 {{Dereference of null pointer}}
+}
+#if defined(MIPS_SUPPRESSED)
+void evalReferences_addrspace(const Shape &S) {
+  const auto &C = dyn_cast<DEVICE Circle>(S);
+  (void)C;
+}
+#endif
 #endif
 
 void evalNonNullParamNonNullReturnReference(const Shape &S) {