Index: lib/Driver/Driver.cpp
===================================================================
--- lib/Driver/Driver.cpp
+++ lib/Driver/Driver.cpp
@@ -481,6 +481,17 @@
     Target.setVendorName("intel");
   }
 
+  // If target is MIPS and there is no explicit `-target` option,
+  // adjust the target triple accordingly to provided ABI name.
+  if (Target.isMIPS() && !Args.getLastArg(options::OPT_target)) {
+    if (Arg *A = Args.getLastArg(options::OPT_mabi_EQ))
+      Target = llvm::StringSwitch<llvm::Triple>(A->getValue())
+                   .Case("32", Target.get32BitArchVariant())
+                   .Case("n32", Target.get64BitArchVariant())
+                   .Case("64", Target.get64BitArchVariant())
+                   .Default(Target);
+  }
+
   return Target;
 }
 
Index: test/Driver/mips-target-abi.c
===================================================================
--- /dev/null
+++ test/Driver/mips-target-abi.c
@@ -0,0 +1,24 @@
+// Check default target triple adjusting by ABI option.
+//
+// REQUIRES: mips-default-target
+//
+// RUN: %clang -mabi=32 -### %s 2>&1 | FileCheck -check-prefix=O32 %s
+// O32: "-triple" "mips{{[^"]*}}"
+// O32: "-target-cpu" "mips32r2"
+// O32: "-target-abi" "o32"
+// O32: ld{{.*}}"
+// O32: "-m" "elf32btsmip"
+
+// RUN: %clang -mabi=n32 -### %s 2>&1 | FileCheck -check-prefix=N32 %s
+// N32: "-triple" "mips64{{[^"]*}}"
+// N32: "-target-cpu" "mips64r2"
+// N32: "-target-abi" "n32"
+// N32: ld{{.*}}"
+// N32: "-m" "elf32btsmipn32"
+
+// RUN: %clang -mabi=64 -### %s 2>&1 | FileCheck -check-prefix=N64 %s
+// N64: "-triple" "mips64{{[^"]*}}"
+// N64: "-target-cpu" "mips64r2"
+// N64: "-target-abi" "n64"
+// N64: ld{{.*}}"
+// N64: "-m" "elf64btsmip"
Index: test/lit.cfg.py
===================================================================
--- test/lit.cfg.py
+++ test/lit.cfg.py
@@ -136,6 +136,10 @@
 if os.path.exists('/dev/fd/0') and sys.platform not in ['cygwin']:
     config.available_features.add('dev-fd-fs')
 
+# Test that default target triple is mips*
+if re.match(r'^mips*', config.target_triple):
+    config.available_features.add('mips-default-target')
+
 # Not set on native MS environment.
 if not re.match(r'.*-(windows-msvc)$', config.target_triple):
     config.available_features.add('non-ms-sdk')