Index: llvm/trunk/include/llvm/ADT/Triple.h
===================================================================
--- llvm/trunk/include/llvm/ADT/Triple.h
+++ llvm/trunk/include/llvm/ADT/Triple.h
@@ -56,9 +56,9 @@
     bpfeb,          // eBPF or extended BPF or 64-bit BPF (big endian)
     hexagon,        // Hexagon: hexagon
     mips,           // MIPS: mips, mipsallegrex
-    mipsel,         // MIPSEL: mipsel, mipsallegrexel
-    mips64,         // MIPS64: mips64
-    mips64el,       // MIPS64EL: mips64el
+    mipsel,         // MIPSEL: mipsel, mipsallegrexe
+    mips64,         // MIPS64: mips64, mipsn32
+    mips64el,       // MIPS64EL: mips64el, mipsn32el
     msp430,         // MSP430: msp430
     nios2,          // NIOSII: nios2
     ppc,            // PPC: powerpc
Index: llvm/trunk/lib/Support/Triple.cpp
===================================================================
--- llvm/trunk/lib/Support/Triple.cpp
+++ llvm/trunk/lib/Support/Triple.cpp
@@ -401,8 +401,8 @@
     .Case("msp430", Triple::msp430)
     .Cases("mips", "mipseb", "mipsallegrex", Triple::mips)
     .Cases("mipsel", "mipsallegrexel", Triple::mipsel)
-    .Cases("mips64", "mips64eb", Triple::mips64)
-    .Case("mips64el", Triple::mips64el)
+    .Cases("mips64", "mips64eb", "mipsn32", Triple::mips64)
+    .Cases("mips64el", "mipsn32el", Triple::mips64el)
     .Case("nios2", Triple::nios2)
     .Case("r600", Triple::r600)
     .Case("amdgcn", Triple::amdgcn)
@@ -711,6 +711,14 @@
           ObjectFormat = parseFormat(Components[3]);
         }
       }
+    } else {
+      Environment = StringSwitch<Triple::EnvironmentType>(Components[0])
+                        .StartsWith("mipsn32", Triple::GNUABIN32)
+                        .StartsWith("mips64", Triple::GNUABI64)
+                        .StartsWith("mipsisa64", Triple::GNUABI64)
+                        .StartsWith("mipsisa32", Triple::GNU)
+                        .Cases("mips", "mipsel",  Triple::GNU)
+                        .Default(UnknownEnvironment);
     }
   }
   if (ObjectFormat == UnknownObjectFormat)
Index: llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp
===================================================================
--- llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp
+++ llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp
@@ -55,6 +55,8 @@
     return MipsABIInfo::N32();
   if (Options.getABIName().startswith("n64"))
     return MipsABIInfo::N64();
+  if (TT.getEnvironment() == llvm::Triple::GNUABIN32)
+    return MipsABIInfo::N32();
   assert(Options.getABIName().empty() && "Unknown ABI option for MIPS");
 
   if (TT.isMIPS64())
Index: llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
===================================================================
--- llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
+++ llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
@@ -13,6 +13,7 @@
 //
 
 #include "MCTargetDesc/MipsAsmBackend.h"
+#include "MCTargetDesc/MipsABIInfo.h"
 #include "MCTargetDesc/MipsFixupKinds.h"
 #include "MCTargetDesc/MipsMCExpr.h"
 #include "MCTargetDesc/MipsMCTargetDesc.h"
@@ -572,6 +573,6 @@
                                          const MCSubtargetInfo &STI,
                                          const MCRegisterInfo &MRI,
                                          const MCTargetOptions &Options) {
-  return new MipsAsmBackend(T, MRI, STI.getTargetTriple(), STI.getCPU(),
-                            Options.ABIName == "n32");
+  MipsABIInfo ABI = MipsABIInfo::computeTargetABI(STI.getTargetTriple(), STI.getCPU(), Options);
+  return new MipsAsmBackend(T, MRI, STI.getTargetTriple(), STI.getCPU(), ABI.IsN32());
 }
Index: llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
===================================================================
--- llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
+++ llvm/trunk/lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
@@ -59,6 +59,10 @@
   if (TheTriple.getEnvironment() == Triple::GNUABI64)
     UseIntegratedAssembler = true;
 
+  // Enable IAS by default for Debian mipsn32/mipsn32el.
+  if (TheTriple.getEnvironment() == Triple::GNUABIN32)
+    UseIntegratedAssembler = true;
+
   // Enable IAS by default for Android mips64el that uses N64 ABI.
   if (TheTriple.getArch() == Triple::mips64el && TheTriple.isAndroid())
     UseIntegratedAssembler = true;
Index: llvm/trunk/test/MC/Mips/elf-N32.s
===================================================================
--- llvm/trunk/test/MC/Mips/elf-N32.s
+++ llvm/trunk/test/MC/Mips/elf-N32.s
@@ -2,6 +2,10 @@
 
 // RUN: llvm-mc -filetype=obj -triple=mips64-linux-gnu -mcpu=mips3 \
 // RUN:         -target-abi=n32  %s -o - | llvm-readobj -r | FileCheck %s
+// RUN: llvm-mc -filetype=obj -triple=mips64-linux-gnuabin32 -mcpu=mips3 \
+// RUN:          %s -o - | llvm-readobj -r | FileCheck %s
+// RUN: llvm-mc -filetype=obj -triple=mipsn32 -mcpu=mips3 \
+// RUN:          %s -o - | llvm-readobj -r | FileCheck %s
 
 // CHECK:      Relocations [
 // CHECK-NEXT:   Section (3) .rela.text {
Index: llvm/trunk/unittests/ADT/TripleTest.cpp
===================================================================
--- llvm/trunk/unittests/ADT/TripleTest.cpp
+++ llvm/trunk/unittests/ADT/TripleTest.cpp
@@ -366,6 +366,59 @@
   EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
   EXPECT_EQ(Triple::Linux, T.getOS());
   EXPECT_EQ(Triple::GNUABI64, T.getEnvironment());
+  T = Triple("mips64el");
+  EXPECT_EQ(Triple::mips64el, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::GNUABI64, T.getEnvironment());
+
+  T = Triple("mips64-unknown-linux-gnuabi64");
+  EXPECT_EQ(Triple::mips64, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::Linux, T.getOS());
+  EXPECT_EQ(Triple::GNUABI64, T.getEnvironment());
+  T = Triple("mips64");
+  EXPECT_EQ(Triple::mips64, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::GNUABI64, T.getEnvironment());
+
+  T = Triple("mips64el-unknown-linux-gnuabin32");
+  EXPECT_EQ(Triple::mips64el, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::Linux, T.getOS());
+  EXPECT_EQ(Triple::GNUABIN32, T.getEnvironment());
+  T = Triple("mipsn32el");
+  EXPECT_EQ(Triple::mips64el, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::GNUABIN32, T.getEnvironment());
+
+  T = Triple("mips64-unknown-linux-gnuabin32");
+  EXPECT_EQ(Triple::mips64, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::Linux, T.getOS());
+  EXPECT_EQ(Triple::GNUABIN32, T.getEnvironment());
+  T = Triple("mipsn32");
+  EXPECT_EQ(Triple::mips64, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::GNUABIN32, T.getEnvironment());
+
+  T = Triple("mipsel-unknown-linux-gnu");
+  EXPECT_EQ(Triple::mipsel, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::Linux, T.getOS());
+  EXPECT_EQ(Triple::GNU, T.getEnvironment());
+  T = Triple("mipsel");
+  EXPECT_EQ(Triple::mipsel, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::GNU, T.getEnvironment());
+
+  T = Triple("mips-unknown-linux-gnu");
+  EXPECT_EQ(Triple::mips, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::GNU, T.getEnvironment());
+  T = Triple("mips");
+  EXPECT_EQ(Triple::mips, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::GNU, T.getEnvironment());
 
   T = Triple("arm-oe-linux-gnueabi");
   EXPECT_EQ(Triple::arm, T.getArch());