[ARM] Use getSignedConstant. NFC

Author: topperc

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -6051,7 +6051,7 @@ static SDValue LowerFP_TO_INT_SAT(SDValue Op, SelectionDAG &DAG,
                             DAG.getConstant((1 << BW) - 1, DL, VT));
   if (IsSigned)
     Max = DAG.getNode(ISD::SMAX, DL, VT, Max,
-                      DAG.getConstant(-(1 << BW), DL, VT));
+                      DAG.getSignedConstant(-(1 << BW), DL, VT));
   return Max;
 }
 

llvm/lib/Target/ARM/ARMInstrThumb2.td

@@ -77,8 +77,8 @@ def t2_so_imm_not_XFORM : SDNodeXForm<imm, [{
 
 // t2_so_imm_neg_XFORM - Return the negation of a t2_so_imm value
 def t2_so_imm_neg_XFORM : SDNodeXForm<imm, [{
-  return CurDAG->getTargetConstant(-((int)N->getZExtValue()), SDLoc(N),
-                                   MVT::i32);
+  return CurDAG->getSignedConstant(-((int)N->getZExtValue()), SDLoc(N),
+                                   MVT::i32, /*isTarget=*/true);
 }]>;
 
 // so_imm_notSext_XFORM - Return a so_imm value packed into the format