[AMDGPU] Fix expansion for v_abs_v4i16

Author: tgymnich

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

@@ -791,7 +791,7 @@ SITargetLowering::SITargetLowering(const TargetMachine &TM,
     for (MVT VT : {MVT::v4i16, MVT::v8i16, MVT::v16i16, MVT::v32i16})
       // Split vector operations.
       setOperationAction({ISD::SHL, ISD::SRA, ISD::SRL, ISD::ADD, ISD::SUB,
-                          ISD::MUL, ISD::SMIN, ISD::SMAX, ISD::UMIN, ISD::UMAX,
+                          ISD::MUL, ISD::ABS, ISD::SMIN, ISD::SMAX, ISD::UMIN, ISD::UMAX,
                           ISD::UADDSAT, ISD::SADDSAT, ISD::USUBSAT,
                           ISD::SSUBSAT},
                          VT, Custom);
@@ -5804,6 +5804,7 @@ SDValue SITargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
     return lowerTRAP(Op, DAG);
   case ISD::DEBUGTRAP:
     return lowerDEBUGTRAP(Op, DAG);
+  case ISD::ABS:
   case ISD::FABS:
   case ISD::FNEG:
   case ISD::FCANONICALIZE: