diff --git a/clang/lib/Driver/ToolChains/Arch/X86.cpp b/clang/lib/Driver/ToolChains/Arch/X86.cpp
--- a/clang/lib/Driver/ToolChains/Arch/X86.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/X86.cpp
@@ -102,18 +102,27 @@
   if (Is64Bit)
     return "x86-64";
 
-  switch (Triple.getOS()) {
-  case llvm::Triple::NetBSD:
-    return "i486";
-  case llvm::Triple::Haiku:
-  case llvm::Triple::OpenBSD:
-    return "i586";
-  case llvm::Triple::FreeBSD:
-    return "i686";
-  default:
-    // Fallback to p4.
-    return "pentium4";
+  StringRef ArchName = Triple.getArchName();
+
+  if (ArchName == "i386") {
+    switch (Triple.getOS()) {
+    case llvm::Triple::NetBSD:
+      return "i486";
+    case llvm::Triple::Haiku:
+    case llvm::Triple::OpenBSD:
+      return "i586";
+    case llvm::Triple::FreeBSD:
+      return "i686";
+    default:
+      // Fallback to p4.
+      return "pentium4";
+    }
   }
+
+  if (ArchName == "i786" || ArchName == "i886" || ArchName == "i986")
+    return "pentium4";
+
+  return std::string(ArchName);
 }
 
 void x86::getX86TargetFeatures(const Driver &D, const llvm::Triple &Triple,
diff --git a/clang/test/Driver/cl-x86-flags.c b/clang/test/Driver/cl-x86-flags.c
--- a/clang/test/Driver/cl-x86-flags.c
+++ b/clang/test/Driver/cl-x86-flags.c
@@ -133,5 +133,11 @@
 // tune: "-target-cpu" "sandybridge"
 // tune-SAME: "-tune-cpu" "haswell"
 
+// RUN: %clang_cl --target=i686-unknown-unknown -### -- 2>&1 %s | FileCheck -check-prefix=i686 %s
+// i686: "-target-cpu" "i686"
+
+// RUN: %clang_cl --target=i786-unknown-unknown -### -- 2>&1 %s | FileCheck -check-prefix=i786 %s
+// i786: "-target-cpu" "pentium4"
+
 void f(void) {
 }
diff --git a/clang/test/Driver/nacl-direct.c b/clang/test/Driver/nacl-direct.c
--- a/clang/test/Driver/nacl-direct.c
+++ b/clang/test/Driver/nacl-direct.c
@@ -6,7 +6,7 @@
 // RUN:   | FileCheck --check-prefix=CHECK-I686 %s
 // CHECK-I686: "-cc1"
 // CHECK-I686-NOT: "-fno-use-init-array"
-// CHECK-I686: "-target-cpu" "pentium4"
+// CHECK-I686: "-target-cpu" "i686"
 // CHECK-I686: "-resource-dir" "foo"
 // CHECK-I686: "-internal-isystem" "foo{{/|\\\\}}include"
 // CHECK-I686: "-internal-isystem" "{{.*}}{{/|\\\\}}..{{/|\\\\}}i686-nacl{{/|\\\\}}usr{{/|\\\\}}include"