[Mips] Use getSignedConstant() for signed values (#116405)

This also adds a getSignedTargetConstant() helper, as these seem to be
fairly common in general.

Author: nikic

llvm/include/llvm/CodeGen/SelectionDAG.h

@@ -700,6 +700,10 @@ class SelectionDAG {
                             bool isOpaque = false) {
     return getConstant(Val, DL, VT, true, isOpaque);
   }
+  SDValue getSignedTargetConstant(int64_t Val, const SDLoc &DL, EVT VT,
+                                  bool isOpaque = false) {
+    return getSignedConstant(Val, DL, VT, true, isOpaque);
+  }
 
   /// Create a true or false constant of type \p VT using the target's
   /// BooleanContent for type \p OpVT.

llvm/lib/Target/Mips/MipsISelDAGToDAG.h

@@ -133,6 +133,11 @@ class MipsDAGToDAGISel : public SelectionDAGISel {
     return CurDAG->getTargetConstant(Imm, SDLoc(Node), Node->getValueType(0));
   }
 
+  inline SDValue getSignedImm(const SDNode *Node, int64_t Imm) {
+    return CurDAG->getSignedTargetConstant(Imm, SDLoc(Node),
+                                           Node->getValueType(0));
+  }
+
   virtual void processFunctionAfterISel(MachineFunction &MF) = 0;
 
   bool SelectInlineAsmMemoryOperand(const SDValue &Op,

llvm/lib/Target/Mips/MipsISelLowering.cpp

@@ -2360,9 +2360,9 @@ SDValue MipsTargetLowering::lowerVAARG(SDValue Op, SelectionDAG &DAG) const {
         ISD::ADD, DL, VAList.getValueType(), VAList,
         DAG.getConstant(Align.value() - 1, DL, VAList.getValueType()));
 
-    VAList = DAG.getNode(
-        ISD::AND, DL, VAList.getValueType(), VAList,
-        DAG.getConstant(-(int64_t)Align.value(), DL, VAList.getValueType()));
+    VAList = DAG.getNode(ISD::AND, DL, VAList.getValueType(), VAList,
+                         DAG.getSignedConstant(-(int64_t)Align.value(), DL,
+                                               VAList.getValueType()));
   }
 
   // Increment the pointer, VAList, to the next vaarg.
@@ -4289,7 +4289,7 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       EVT Type = Op.getValueType();
       int64_t Val = C->getSExtValue();
       if (isInt<16>(Val)) {
-        Result = DAG.getTargetConstant(Val, DL, Type);
+        Result = DAG.getSignedTargetConstant(Val, DL, Type);
         break;
       }
     }
@@ -4319,7 +4319,7 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       EVT Type = Op.getValueType();
       int64_t Val = C->getSExtValue();
       if ((isInt<32>(Val)) && ((Val & 0xffff) == 0)){
-        Result = DAG.getTargetConstant(Val, DL, Type);
+        Result = DAG.getSignedTargetConstant(Val, DL, Type);
         break;
       }
     }
@@ -4329,7 +4329,7 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       EVT Type = Op.getValueType();
       int64_t Val = C->getSExtValue();
       if ((Val >= -65535) && (Val <= -1)) {
-        Result = DAG.getTargetConstant(Val, DL, Type);
+        Result = DAG.getSignedTargetConstant(Val, DL, Type);
         break;
       }
     }
@@ -4339,7 +4339,7 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
       EVT Type = Op.getValueType();
       int64_t Val = C->getSExtValue();
       if ((isInt<15>(Val))) {
-        Result = DAG.getTargetConstant(Val, DL, Type);
+        Result = DAG.getSignedTargetConstant(Val, DL, Type);
         break;
       }
     }

llvm/lib/Target/Mips/MipsInstrInfo.td

@@ -1199,7 +1199,9 @@ def HI16 : SDNodeXForm<imm, [{
 }]>;
 
 // Plus 1.
-def Plus1 : SDNodeXForm<imm, [{ return getImm(N, N->getSExtValue() + 1); }]>;
+def Plus1 : SDNodeXForm<imm, [{
+  return getSignedImm(N, N->getSExtValue() + 1);
+}]>;
 
 // Node immediate is zero (e.g. insve.d)
 def immz : PatLeaf<(imm), [{ return N->getSExtValue() == 0; }]>;