Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -755,9 +755,14 @@
       break;
     case llvm::Triple::EABIHF:
     case llvm::Triple::EABI:
-    default:
       ABIName = "aapcs";
       break;
+    default:
+      if (Triple.getOS() == llvm::Triple::NetBSD)
+        ABIName = "apcs-gnu";
+      else
+        ABIName = "aapcs";
+      break;
     }
   }
   CmdArgs.push_back("-target-abi");
Index: test/Driver/arm-abi.c
===================================================================
--- test/Driver/arm-abi.c
+++ test/Driver/arm-abi.c
@@ -20,6 +20,14 @@
 // RUN: %clang -target arm--windows-gnueabi %s -### -o %t.o 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-AAPCS %s
 
+// NetBSD defaults to apcs-gnu, but can also use aapcs
+// RUN: %clang -target arm--netbsd- %s -### -o %t.o 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-APCS-GNU %s
+// RUN: %clang -target arm--netbsd-eabi %s -### -o %t.o 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-AAPCS %s
+// RUN: %clang -target arm--netbsd-eabihf %s -### -o %t.o 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-AAPCS %s
+
 // Otherwise, ABI is celected based on environment
 // RUN: %clang -target arm---android %s -### -o %t.o 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-AAPCS-LINUX %s