Index: lib/Target/Mips/Mips64InstrInfo.td
===================================================================
--- lib/Target/Mips/Mips64InstrInfo.td
+++ lib/Target/Mips/Mips64InstrInfo.td
@@ -363,6 +363,16 @@
 //  Arbitrary patterns that map to one or more instructions
 //===----------------------------------------------------------------------===//
 
+// Add/sub with carry
+def : MipsPat<(subc GPR64:$lhs, GPR64:$rhs),
+              (DSUBu GPR64:$lhs, GPR64:$rhs)>, ISA_MIPS3;
+let AdditionalPredicates = [NotDSP] in {
+  def : MipsPat<(addc GPR64:$lhs, GPR64:$rhs),
+                (DADDu GPR64:$lhs, GPR64:$rhs)>, ISA_MIPS3;
+  def : MipsPat<(addc  GPR64:$src, immSExt16:$imm),
+                (DADDiu GPR64:$src, imm:$imm)>, ISA_MIPS3;
+}
+
 // extended loads
 def : MipsPat<(i64 (extloadi1  addr:$src)), (LB64 addr:$src)>;
 def : MipsPat<(i64 (extloadi8  addr:$src)), (LB64 addr:$src)>;
Index: lib/Target/Mips/MipsSEISelDAGToDAG.cpp
===================================================================
--- lib/Target/Mips/MipsSEISelDAGToDAG.cpp
+++ lib/Target/Mips/MipsSEISelDAGToDAG.cpp
@@ -240,9 +240,27 @@
   SDValue LHS = Node->getOperand(0), RHS = Node->getOperand(1);
   EVT VT = LHS.getValueType();
 
-  SDNode *Carry = CurDAG->getMachineNode(Mips::SLTu, DL, VT, Ops);
-  SDNode *AddCarry = CurDAG->getMachineNode(Mips::ADDu, DL, VT,
-                                            SDValue(Carry, 0), RHS);
+  unsigned SltOp = Mips::SLTu;
+  unsigned AddOp = Mips::ADDu;
+  if (VT == MVT::i64) {
+    SltOp = Mips::SLTu64;
+    AddOp = Mips::DADDu;
+  }
+
+  SDValue Carry = SDValue(CurDAG->getMachineNode(SltOp, DL, VT, Ops), 0);
+  if (SltOp == Mips::SLTu64) {
+    // On 64-bit targets, sltu produces an i64 but our backend currently says
+    // that SLTu64 produces an i32. We need to fix this in the long run but for
+    // now, just make the DAG type-correct by asserting the upper bits are zero.
+    Carry = SDValue(CurDAG->getMachineNode(
+                        Mips::SUBREG_TO_REG, DL, VT,
+                        CurDAG->getTargetConstant(0, VT), Carry,
+                        CurDAG->getTargetConstant(Mips::sub_32, MVT::i32)),
+                    0);
+  }
+
+  SDNode *AddCarry = CurDAG->getMachineNode(AddOp, DL, VT, Carry, RHS);
+
   return CurDAG->SelectNodeTo(Node, MOp, VT, MVT::Glue, LHS,
                               SDValue(AddCarry, 0));
 }
@@ -641,7 +659,9 @@
 
   case ISD::SUBE: {
     SDValue InFlag = Node->getOperand(2);
-    Result = selectAddESubE(Mips::SUBu, InFlag, InFlag.getOperand(0), DL, Node);
+    unsigned SubOp =
+        Node->getValueType(0) == MVT::i64 ? Mips::DSUBu : Mips::SUBu;
+    Result = selectAddESubE(SubOp, InFlag, InFlag.getOperand(0), DL, Node);
     return std::make_pair(true, Result);
   }
 
@@ -649,7 +669,9 @@
     if (Subtarget->hasDSP()) // Select DSP instructions, ADDSC and ADDWC.
       break;
     SDValue InFlag = Node->getOperand(2);
-    Result = selectAddESubE(Mips::ADDu, InFlag, InFlag.getValue(0), DL, Node);
+    unsigned AddOp =
+        Node->getValueType(0) == MVT::i64 ? Mips::DADDu : Mips::ADDu;
+    Result = selectAddESubE(AddOp, InFlag, InFlag.getValue(0), DL, Node);
     return std::make_pair(true, Result);
   }
 
Index: test/CodeGen/Mips/llvm-ir/add.ll
===================================================================
--- /dev/null
+++ test/CodeGen/Mips/llvm-ir/add.ll
@@ -0,0 +1,95 @@
+; RUN: llc < %s -march=mips -mcpu=mips2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-32BIT -check-prefix=M2
+; RUN: llc < %s -march=mips -mcpu=mips32 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-32BIT -check-prefix=32R1-R2 -check-prefix=32R1
+; RUN: llc < %s -march=mips -mcpu=mips32r2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-32BIT -check-prefix=32R1-R2 -check-prefix=32R2
+; RUN: llc < %s -march=mips -mcpu=mips32r6 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-32BIT -check-prefix=32R6
+; RUN: llc < %s -march=mips64 -mcpu=mips4 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-64BIT -check-prefix=M4
+; RUN: llc < %s -march=mips64 -mcpu=mips64 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-64BIT -check-prefix=64R1-R2
+; RUN: llc < %s -march=mips64 -mcpu=mips64r2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-64BIT -check-prefix=64R1-R2
+; RUN: llc < %s -march=mips64 -mcpu=mips64r6 | FileCheck %s \
+; RUN:     -check-prefix=ALL -check-prefix=ALL-64BIT -check-prefix=64R6
+
+; FIXME: We should be able to have signext on the return value without incurring
+;        a sign extend.
+define i8 @add_i8(i8 signext %a, i8 signext %b) {
+entry:
+; ALL-LABEL: add_i8:
+
+; ALL:           addu $2, $4, $5
+
+  %r = add i8 %a, %b
+  ret i8 %r
+}
+
+; FIXME: We should be able to have signext on the return value without incurring
+;        a sign extend.
+define i16 @add_i16(i16 signext %a, i16 signext %b) {
+entry:
+; ALL-LABEL: add_i16:
+
+; ALL:           addu $2, $4, $5
+
+  %r = add i16 %a, %b
+  ret i16 %r
+}
+
+define signext i32 @add_i32(i32 signext %a, i32 signext %b) {
+entry:
+; ALL-LABEL: add_i32:
+
+; ALL:           addu $2, $4, $5
+
+  %r = add i32 %a, %b
+  ret i32 %r
+}
+
+define signext i64 @add_i64(i64 signext %a, i64 signext %b) {
+entry:
+; ALL-LABEL: add_i64:
+
+; ALL-32BIT-DAG: addu [[R1:\$3]], $5, $7
+; ALL-32BIT-DAG: sltu [[T0:\$[0-9]+]], [[R1]], $7
+; ALL-32BIT-DAG: addu [[T1:\$[0-9]+]], [[T0]], $6
+; ALL-32BIT-DAG: addu $2, $4, [[T1]]
+
+; ALL-64BIT:     daddu $2, $4, $5
+
+  %r = add i64 %a, %b
+  ret i64 %r
+}
+
+define signext i128 @add_i128(i128 signext %a, i128 signext %b) {
+entry:
+; ALL-LABEL: add_i128:
+
+; ALL-32BIT-DAG: lw      [[A3:\$[0-9]+]], 28($sp)
+; ALL-32BIT-DAG: addu    [[T0:\$[0-9]+]], $7, [[A3]]
+; ALL-32BIT-DAG: sltu    [[T1:\$[0-9]+]], [[T0]], [[A3]]
+; ALL-32BIT-DAG: lw      [[A2:\$[0-9]+]], 24($sp)
+; ALL-32BIT-DAG: addu    [[T2:\$[0-9]+]], [[T1]], [[A2]]
+; ALL-32BIT-DAG: addu    [[T3:\$[0-9]+]], $6, [[T2]]
+; ALL-32BIT-DAG: sltu    [[T4:\$[0-9]+]], [[T3]], [[A2]]
+; ALL-32BIT-DAG: lw      [[A1:\$[0-9]+]], 20($sp)
+; ALL-32BIT-DAG: addu    [[T5:\$[0-9]+]], [[T4]], [[A1]]
+; ALL-32BIT-DAG: lw      [[A0:\$[0-9]+]], 16($sp)
+; ALL-32BIT-DAG: addu    [[R1:\$3]], [[R3:\$5]], [[T5]]
+; ALL-32BIT-DAG: sltu    [[T6:\$[0-9]+]], [[R1]], [[A1]]
+; ALL-32BIT-DAG: addu    [[T7:\$[0-9]+]], [[T6]], [[A0]]
+; ALL-32BIT-DAG: addu    $2, [[R2:\$4]], [[T7]]
+; ALL-32BIT-DAG: move    [[R2]], [[T3]]
+; ALL-32BIT-DAG: move    [[R3]], [[T0]]
+
+; ALL-64BIT-DAG: daddu [[R0:\$3]], $5, $7
+; ALL-64BIT-DAG: sltu [[T1:\$[0-9]+]], [[R0]], $7
+; ALL-64BIT-DAG: daddu [[T2:\$[0-9]+]], [[T1]], $6
+; ALL-64BIT-DAG: daddu $2, $4, [[T2]]
+
+  %r = add i128 %a, %b
+  ret i128 %r
+}
Index: test/CodeGen/Mips/llvm-ir/sub.ll
===================================================================
--- /dev/null
+++ test/CodeGen/Mips/llvm-ir/sub.ll
@@ -0,0 +1,94 @@
+; RUN: llc < %s -march=mips -mcpu=mips2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-32BIT -check-prefix=M2
+; RUN: llc < %s -march=mips -mcpu=mips32 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-32BIT -check-prefix=32R1-R2 -check-prefix=32R1
+; RUN: llc < %s -march=mips -mcpu=mips32r2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-32BIT -check-prefix=32R1-R2 -check-prefix=32R2
+; RUN: llc < %s -march=mips -mcpu=mips32r6 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-32BIT -check-prefix=32R6
+; RUN: llc < %s -march=mips64 -mcpu=mips4 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-64BIT -check-prefix=M4
+; RUN: llc < %s -march=mips64 -mcpu=mips64 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-64BIT -check-prefix=64R1-R2
+; RUN: llc < %s -march=mips64 -mcpu=mips64r2 | FileCheck %s \
+; RUN:    -check-prefix=ALL -check-prefix=ALL-64BIT -check-prefix=64R1-R2
+; RUN: llc < %s -march=mips64 -mcpu=mips64r6 | FileCheck %s \
+; RUN:     -check-prefix=ALL -check-prefix=ALL-64BIT -check-prefix=64R6
+
+; FIXME: We should be able to have signext on the return value without incurring
+;        a sign extend.
+define i8 @sub_i8(i8 signext %a, i8 signext %b) {
+entry:
+; ALL-LABEL: sub_i8:
+
+; ALL:           subu $2, $4, $5
+
+  %r = sub i8 %a, %b
+  ret i8 %r
+}
+
+; FIXME: We should be able to have signext on the return value without incurring
+;        a sign extend.
+define i16 @sub_i16(i16 signext %a, i16 signext %b) {
+entry:
+; ALL-LABEL: sub_i16:
+
+; ALL:           subu $2, $4, $5
+
+  %r = sub i16 %a, %b
+  ret i16 %r
+}
+
+define signext i32 @sub_i32(i32 signext %a, i32 signext %b) {
+entry:
+; ALL-LABEL: sub_i32:
+
+; ALL:           subu $2, $4, $5
+
+  %r = sub i32 %a, %b
+  ret i32 %r
+}
+
+define signext i64 @sub_i64(i64 signext %a, i64 signext %b) {
+entry:
+; ALL-LABEL: sub_i64:
+
+; ALL-32BIT-DAG: subu [[R1:\$3]], $5, $7
+; ALL-32BIT-DAG: sltu [[T0:\$[0-9]+]], $5, $7
+; ALL-32BIT-DAG: addu [[T1:\$[0-9]+]], [[T0]], $6
+; ALL-32BIT-DAG: subu $2, $4, [[T1]]
+
+; ALL-64BIT:     dsubu $2, $4, $5
+
+  %r = sub i64 %a, %b
+  ret i64 %r
+}
+
+define signext i128 @sub_i128(i128 signext %a, i128 signext %b) {
+entry:
+; ALL-LABEL: sub_i128:
+
+; ALL-32BIT-DAG: lw      [[A1:\$[0-9]+]], 20($sp)
+; ALL-32BIT-DAG: sltu    [[T0:\$[0-9]+]], $5, [[A1]]
+; ALL-32BIT-DAG: lw      [[A0:\$[0-9]+]], 16($sp)
+; ALL-32BIT-DAG: addu    [[T1:\$[0-9]+]], [[T0]], [[A0]]
+; ALL-32BIT-DAG: lw      [[A2:\$[0-9]+]], 24($sp)
+; ALL-32BIT-DAG: lw      [[A3:\$[0-9]+]], 28($sp)
+; ALL-32BIT-DAG: subu    [[T2:\$[0-9]+]], $7, [[A3]]
+; ALL-32BIT-DAG: subu    $2, $4, [[T1]]
+; ALL-32BIT-DAG: sltu    [[T3:\$[0-9]+]], $6, [[A2]]
+; ALL-32BIT-DAG: addu    [[T4:\$[0-9]+]], [[T3]], [[A1]]
+; ALL-32BIT-DAG: subu    $3, $5, [[T4]]
+; ALL-32BIT-DAG: sltu    [[T5:\$[0-9]+]], $7, [[A3]]
+; ALL-32BIT-DAG: addu    [[T6:\$[0-9]+]], [[T5]], [[A2]]
+; ALL-32BIT-DAG: subu    $4, $6, [[T6]]
+; ALL-32BIT-DAG: move    $5, [[T2]]
+
+; ALL-64BIT-DAG: dsubu $3, $5, $7
+; ALL-64BIT-DAG: sltu [[T1:\$[0-9]+]], $5, $7
+; ALL-64BIT-DAG: daddu [[T2:\$[0-9]+]], [[T1]], $6
+; ALL-64BIT-DAG: dsubu $2, $4, [[T2]]
+
+  %r = sub i128 %a, %b
+  ret i128 %r
+}