Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -4091,9 +4091,10 @@
   if (Triple.isOSWindows() && (Triple.getArch() == llvm::Triple::arm ||
                                Triple.getArch() == llvm::Triple::thumb)) {
     unsigned Offset = Triple.getArch() == llvm::Triple::arm ? 4 : 6;
-    unsigned Version;
-    Triple.getArchName().substr(Offset).getAsInteger(10, Version);
-    if (Version < 7)
+    unsigned Version = 0;
+    bool Failure =
+        Triple.getArchName().substr(Offset).consumeInteger(10, Version);
+    if (Failure || Version < 7)
       D.Diag(diag::err_target_unsupported_arch) << Triple.getArchName()
                                                 << TripleStr;
   }
Index: clang/test/Driver/windows-thumbv7em.cpp
===================================================================
--- /dev/null
+++ clang/test/Driver/windows-thumbv7em.cpp
@@ -0,0 +1,5 @@
+// RUN: %clang_cpp --target=thumbv7em-none-windows-eabi-coff \
+// RUN: -mcpu=cortex-m7 -c %s -o /dev/null 2>&1 \
+// RUN: | FileCheck --allow-empty %s
+
+// CHECK-NOT: error: the target architecture 'thumbv7em' is not supported by the target 'thumbv7em-none-windows-eabi'