diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.cpp b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
--- a/clang/lib/Driver/ToolChains/Arch/ARM.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
@@ -314,6 +314,10 @@
 
   // FIXME: this is invalid for WindowsCE
   case llvm::Triple::Win32:
+    // It is incorrect to select hard float ABI on MachO platforms if the ABI is
+    // "apcs-gnu".
+    if (Triple.isOSBinFormatMachO() && !useAAPCSForMachO(Triple))
+      return FloatABI::Soft;
     return FloatABI::Hard;
 
   case llvm::Triple::NetBSD:
diff --git a/clang/test/Driver/windows-macho.c b/clang/test/Driver/windows-macho.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Driver/windows-macho.c
@@ -0,0 +1,11 @@
+// RUN: %clang -target armv7-pc-win32-macho -msoft-float -### -c %s 2>&1 \
+// RUN: | FileCheck %s --check-prefix CHECK-SOFTFLOAT
+// CHECK-SOFTFLOAT-NOT: error: unsupported option '-msoft-float' for target 'thumbv7-pc-windows-macho'
+
+// RUN: %clang -target armv7-pc-win32-macho -mhard-float -### -c %s 2>&1 \
+// RUN: | FileCheck %s --check-prefix CHECK-HARDFLOAT
+// CHECK-HARDFLOAT: error: unsupported option '-mhard-float' for target 'thumbv7-pc-windows-macho'
+
+// RUN: %clang -target armv7-pc-win32-macho -### -c %s 2>&1 \
+// RUN: | FileCheck %s --check-prefix CHECK-DEFAULT-SOFTFLOAT-ABI
+// CHECK-DEFAULT-SOFTFLOAT-ABI: "-mfloat-abi" "soft"