[SelectionDAG] Use llvm::Optional<APInt> for FoldValue.

Use llvm::Optional<APInt> instead of std::pair<APInt, bool> with the bool second being used to report success/failure of fold.

1 files changed, 30 insertions, 32 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6dcf271a81c..1e5e0724f08 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -4724,46 +4724,46 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT,
   return V;
 }
 
-static std::pair<APInt, bool> FoldValue(unsigned Opcode, const APInt &C1,
-                                        const APInt &C2) {
+static llvm::Optional<APInt> FoldValue(unsigned Opcode, const APInt &C1,
+                                       const APInt &C2) {
   switch (Opcode) {
-  case ISD::ADD:  return std::make_pair(C1 + C2, true);
-  case ISD::SUB:  return std::make_pair(C1 - C2, true);
-  case ISD::MUL:  return std::make_pair(C1 * C2, true);
-  case ISD::AND:  return std::make_pair(C1 & C2, true);
-  case ISD::OR:   return std::make_pair(C1 | C2, true);
-  case ISD::XOR:  return std::make_pair(C1 ^ C2, true);
-  case ISD::SHL:  return std::make_pair(C1 << C2, true);
-  case ISD::SRL:  return std::make_pair(C1.lshr(C2), true);
-  case ISD::SRA:  return std::make_pair(C1.ashr(C2), true);
-  case ISD::ROTL: return std::make_pair(C1.rotl(C2), true);
-  case ISD::ROTR: return std::make_pair(C1.rotr(C2), true);
-  case ISD::SMIN: return std::make_pair(C1.sle(C2) ? C1 : C2, true);
-  case ISD::SMAX: return std::make_pair(C1.sge(C2) ? C1 : C2, true);
-  case ISD::UMIN: return std::make_pair(C1.ule(C2) ? C1 : C2, true);
-  case ISD::UMAX: return std::make_pair(C1.uge(C2) ? C1 : C2, true);
-  case ISD::SADDSAT: return std::make_pair(C1.sadd_sat(C2), true);
-  case ISD::UADDSAT: return std::make_pair(C1.uadd_sat(C2), true);
-  case ISD::SSUBSAT: return std::make_pair(C1.ssub_sat(C2), true);
-  case ISD::USUBSAT: return std::make_pair(C1.usub_sat(C2), true);
+  case ISD::ADD:  return C1 + C2;
+  case ISD::SUB:  return C1 - C2;
+  case ISD::MUL:  return C1 * C2;
+  case ISD::AND:  return C1 & C2;
+  case ISD::OR:   return C1 | C2;
+  case ISD::XOR:  return C1 ^ C2;
+  case ISD::SHL:  return C1 << C2;
+  case ISD::SRL:  return C1.lshr(C2);
+  case ISD::SRA:  return C1.ashr(C2);
+  case ISD::ROTL: return C1.rotl(C2);
+  case ISD::ROTR: return C1.rotr(C2);
+  case ISD::SMIN: return C1.sle(C2) ? C1 : C2;
+  case ISD::SMAX: return C1.sge(C2) ? C1 : C2;
+  case ISD::UMIN: return C1.ule(C2) ? C1 : C2;
+  case ISD::UMAX: return C1.uge(C2) ? C1 : C2;
+  case ISD::SADDSAT: return C1.sadd_sat(C2);
+  case ISD::UADDSAT: return C1.uadd_sat(C2);
+  case ISD::SSUBSAT: return C1.ssub_sat(C2);
+  case ISD::USUBSAT: return C1.usub_sat(C2);
   case ISD::UDIV:
     if (!C2.getBoolValue())
       break;
-    return std::make_pair(C1.udiv(C2), true);
+    return C1.udiv(C2);
   case ISD::UREM:
     if (!C2.getBoolValue())
       break;
-    return std::make_pair(C1.urem(C2), true);
+    return C1.urem(C2);
   case ISD::SDIV:
     if (!C2.getBoolValue())
       break;
-    return std::make_pair(C1.sdiv(C2), true);
+    return C1.sdiv(C2);
   case ISD::SREM:
     if (!C2.getBoolValue())
       break;
-    return std::make_pair(C1.srem(C2), true);
+    return C1.srem(C2);
   }
-  return std::make_pair(APInt(1, 0), false);
+  return llvm::None;
 }
 
 SDValue SelectionDAG::FoldConstantArithmetic(unsigned Opcode, const SDLoc &DL,
@@ -4771,12 +4771,10 @@ SDValue SelectionDAG::FoldConstantArithmetic(unsigned Opcode, const SDLoc &DL,
                                              const ConstantSDNode *C2) {
   if (C1->isOpaque() || C2->isOpaque())
     return SDValue();
-
-  std::pair<APInt, bool> Folded = FoldValue(Opcode, C1->getAPIntValue(),
-                                            C2->getAPIntValue());
-  if (!Folded.second)
-    return SDValue();
-  return getConstant(Folded.first, DL, VT);
+  if (Optional<APInt> Folded =
+          FoldValue(Opcode, C1->getAPIntValue(), C2->getAPIntValue()))
+    return getConstant(Folded.getValue(), DL, VT);
+  return SDValue();
 }
 
 SDValue SelectionDAG::FoldSymbolOffset(unsigned Opcode, EVT VT,