Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -8251,6 +8251,8 @@
   "invalid transaction abort code">;
 def err_64_bit_builtin_32_bit_tgt : Error<
   "this builtin is only available on 64-bit targets">;
+def err_32_bit_builtin_64_bit_tgt : Error<
+  "this builtin is only available on 32-bit targets">;
 def err_builtin_x64_aarch64_only : Error<
   "this builtin is only available on x86-64 and aarch64 targets">;
 def err_ppc_builtin_only_on_pwr7 : Error<
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -2309,6 +2309,17 @@
     << Arg->getSourceRange();
 }
 
+static bool isX86_32Builtin(unsigned BuiltinID) {
+  // These builtins only work on x86-32 targets.
+  switch (BuiltinID) {
+  case X86::BI__builtin_ia32_readeflags_u32:
+  case X86::BI__builtin_ia32_writeeflags_u32:
+    return true;
+  }
+
+  return false;
+}
+
 bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
   if (BuiltinID == X86::BI__builtin_cpu_supports)
     return SemaBuiltinCpuSupports(*this, TheCall);
@@ -2316,6 +2327,12 @@
   if (BuiltinID == X86::BI__builtin_cpu_is)
     return SemaBuiltinCpuIs(*this, TheCall);
 
+  // Check for 32-bit only builtins on a 64-bit target.
+  const llvm::Triple &TT = Context.getTargetInfo().getTriple();
+  if (TT.getArch() != llvm::Triple::x86 && isX86_32Builtin(BuiltinID))
+    return Diag(TheCall->getCallee()->getLocStart(),
+                diag::err_32_bit_builtin_64_bit_tgt);
+
   // If the intrinsic has rounding or SAE make sure its valid.
   if (CheckX86BuiltinRoundingOrSAE(BuiltinID, TheCall))
     return true;
Index: test/Sema/builtins-x86.c
===================================================================
--- test/Sema/builtins-x86.c
+++ test/Sema/builtins-x86.c
@@ -16,6 +16,11 @@
 typedef unsigned short __mmask16;
 typedef unsigned int __mmask32;
 
+void call_x86_32_builtins(void) {
+  (void)__builtin_ia32_readeflags_u32();                             // expected-error{{this builtin is only available on 32-bit targets}}
+  (void)__builtin_ia32_writeeflags_u32(4);                           // expected-error{{this builtin is only available on 32-bit targets}}
+}
+
 __m128 test__builtin_ia32_cmpps(__m128 __a, __m128 __b) {
   __builtin_ia32_cmpps(__a, __b, 32); // expected-error {{argument should be a value from 0 to 31}}
 }