From c71d6d157f06619d3091d396da71cc2007579b99 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Fri, 8 Mar 2019 11:30:33 +0000
Subject: [PATCH] [DAGCombine] Merge visitSADDO+visitUADDO into visitADDO.
 NFCI.

llvm-svn: 355689
---
 llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 72 +++++++++------------------
 1 file changed, 24 insertions(+), 48 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 9371161..2a01a17 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -295,8 +295,7 @@ namespace {
     SDValue visitADDSAT(SDNode *N);
     SDValue visitSUBSAT(SDNode *N);
     SDValue visitADDC(SDNode *N);
-    SDValue visitSADDO(SDNode *N);
-    SDValue visitUADDO(SDNode *N);
+    SDValue visitADDO(SDNode *N);
     SDValue visitUADDOLike(SDValue N0, SDValue N1, SDNode *N);
     SDValue visitSUBC(SDNode *N);
     SDValue visitSUBO(SDNode *N);
@@ -1493,8 +1492,8 @@ SDValue DAGCombiner::visit(SDNode *N) {
   case ISD::SSUBSAT:
   case ISD::USUBSAT:            return visitSUBSAT(N);
   case ISD::ADDC:               return visitADDC(N);
-  case ISD::SADDO:              return visitSADDO(N);
-  case ISD::UADDO:              return visitUADDO(N);
+  case ISD::SADDO:
+  case ISD::UADDO:              return visitADDO(N);
   case ISD::SUBC:               return visitSUBC(N);
   case ISD::SSUBO:
   case ISD::USUBO:              return visitSUBO(N);
@@ -2416,35 +2415,11 @@ static bool isBooleanFlip(SDValue V, EVT VT, const TargetLowering &TLI) {
   llvm_unreachable("Unsupported boolean content");
 }
 
-// TODO: merge this with DAGCombiner::visitUADDO
-SDValue DAGCombiner::visitSADDO(SDNode *N) {
-  SDValue N0 = N->getOperand(0);
-  SDValue N1 = N->getOperand(1);
-  EVT VT = N0.getValueType();
-  EVT CarryVT = N->getValueType(1);
-  SDLoc DL(N);
-
-  // If the flag result is dead, turn this into an ADD.
-  if (!N->hasAnyUseOfValue(1))
-    return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1),
-                     DAG.getUNDEF(CarryVT));
-
-  // canonicalize constant to RHS.
-  if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
-      !DAG.isConstantIntBuildVectorOrConstantInt(N1))
-    return DAG.getNode(ISD::SADDO, DL, N->getVTList(), N1, N0);
-
-  // fold (saddo x, 0) -> x + no carry out
-  if (isNullOrNullSplat(N1))
-    return CombineTo(N, N0, DAG.getConstant(0, DL, CarryVT));
-
-  return SDValue();
-}
-
-SDValue DAGCombiner::visitUADDO(SDNode *N) {
+SDValue DAGCombiner::visitADDO(SDNode *N) {
   SDValue N0 = N->getOperand(0);
   SDValue N1 = N->getOperand(1);
   EVT VT = N0.getValueType();
+  bool IsSigned = (ISD::SADDO == N->getOpcode());
 
   EVT CarryVT = N->getValueType(1);
   SDLoc DL(N);
@@ -2457,31 +2432,32 @@ SDValue DAGCombiner::visitUADDO(SDNode *N) {
   // canonicalize constant to RHS.
   if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
       !DAG.isConstantIntBuildVectorOrConstantInt(N1))
-    return DAG.getNode(ISD::UADDO, DL, N->getVTList(), N1, N0);
+    return DAG.getNode(N->getOpcode(), DL, N->getVTList(), N1, N0);
 
-  // fold (uaddo x, 0) -> x + no carry out
+  // fold (addo x, 0) -> x + no carry out
   if (isNullOrNullSplat(N1))
     return CombineTo(N, N0, DAG.getConstant(0, DL, CarryVT));
 
-  // If it cannot overflow, transform into an add.
-  if (DAG.computeOverflowKind(N0, N1) == SelectionDAG::OFK_Never)
-    return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1),
-                     DAG.getConstant(0, DL, CarryVT));
+  if (!IsSigned) {
+    // If it cannot overflow, transform into an add.
+    if (DAG.computeOverflowKind(N0, N1) == SelectionDAG::OFK_Never)
+      return CombineTo(N, DAG.getNode(ISD::ADD, DL, VT, N0, N1),
+                       DAG.getConstant(0, DL, CarryVT));
 
-  // fold (uaddo (xor a, -1), 1) -> (usub 0, a) and flip carry.
-  if (isBitwiseNot(N0) && isOneOrOneSplat(N1)) {
-    SDValue Sub = DAG.getNode(ISD::USUBO, DL, N->getVTList(),
-                              DAG.getConstant(0, DL, VT),
-                              N0.getOperand(0));
-    return CombineTo(N, Sub,
-                     flipBoolean(Sub.getValue(1), DL, CarryVT, DAG, TLI));
-  }
+    // fold (uaddo (xor a, -1), 1) -> (usub 0, a) and flip carry.
+    if (isBitwiseNot(N0) && isOneOrOneSplat(N1)) {
+      SDValue Sub = DAG.getNode(ISD::USUBO, DL, N->getVTList(),
+                                DAG.getConstant(0, DL, VT), N0.getOperand(0));
+      return CombineTo(N, Sub,
+                       flipBoolean(Sub.getValue(1), DL, CarryVT, DAG, TLI));
+    }
 
-  if (SDValue Combined = visitUADDOLike(N0, N1, N))
-    return Combined;
+    if (SDValue Combined = visitUADDOLike(N0, N1, N))
+      return Combined;
 
-  if (SDValue Combined = visitUADDOLike(N1, N0, N))
-    return Combined;
+    if (SDValue Combined = visitUADDOLike(N1, N0, N))
+      return Combined;
+  }
 
   return SDValue();
 }
-- 
2.7.4