Index: lib/Target/NVPTX/NVPTXISelLowering.cpp
===================================================================
--- lib/Target/NVPTX/NVPTXISelLowering.cpp
+++ lib/Target/NVPTX/NVPTXISelLowering.cpp
@@ -490,6 +490,7 @@
   setOperationAction(ISD::INTRINSIC_W_CHAIN, MVT::i8, Custom);
 
   for (const auto& Ty : {MVT::i16, MVT::i32, MVT::i64}) {
+    setOperationAction(ISD::ABS,  Ty, Legal);
     setOperationAction(ISD::SMIN, Ty, Legal);
     setOperationAction(ISD::SMAX, Ty, Legal);
     setOperationAction(ISD::UMIN, Ty, Legal);
Index: lib/Target/NVPTX/NVPTXInstrInfo.td
===================================================================
--- lib/Target/NVPTX/NVPTXInstrInfo.td
+++ lib/Target/NVPTX/NVPTXInstrInfo.td
@@ -547,15 +547,14 @@
 // Integer absolute value.  NumBits should be one minus the bit width of RC.
 // This idiom implements the algorithm at
 // http://graphics.stanford.edu/~seander/bithacks.html#IntegerAbs.
-multiclass ABS<RegisterClass RC, int NumBits, string SizeName> {
+multiclass ABS<RegisterClass RC, string SizeName> {
   def : NVPTXInst<(outs RC:$dst), (ins RC:$a),
                   !strconcat("abs", SizeName, " \t$dst, $a;"),
-                  [(set RC:$dst, (xor (add (sra RC:$a, (i32 NumBits)), RC:$a),
-                                      (sra RC:$a, (i32 NumBits))))]>;
+                  [(set RC:$dst, (abs RC:$a))]>;
 }
-defm ABS_16 : ABS<Int16Regs, 15, ".s16">;
-defm ABS_32 : ABS<Int32Regs, 31, ".s32">;
-defm ABS_64 : ABS<Int64Regs, 63, ".s64">;
+defm ABS_16 : ABS<Int16Regs, ".s16">;
+defm ABS_32 : ABS<Int32Regs, ".s32">;
+defm ABS_64 : ABS<Int64Regs, ".s64">;
 
 // Integer min/max.
 defm SMAX : I3<"max.s", smax>;