[SelectionDAG] CSE nodes with differing SDNodeFlags

In the optimizer (GVN etc.) when eliminating redundant nodes with different
flags, the flags are ignored for the purposes of testing for congruence, and
then intersected for the purposes of producing a result that supports the union
of all the uses. This commit makes SelectionDAG's CSE do the same thing,
allowing it to CSE nodes in more cases. This fixes PR26063.

Differential Revision: http://reviews.llvm.org/D15957

llvm-svn: 257940

1 files changed, 22 insertions, 22 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 96bf914701c..893871f9448 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -377,22 +377,6 @@ static void AddNodeIDOperands(FoldingSetNodeID &ID,
   }
 }
 
-/// Add logical or fast math flag values to FoldingSetNodeID value.
-static void AddNodeIDFlags(FoldingSetNodeID &ID, unsigned Opcode,
-                           const SDNodeFlags *Flags) {
-  if (!isBinOpWithFlags(Opcode))
-    return;
-
-  unsigned RawFlags = 0;
-  if (Flags)
-    RawFlags = Flags->getRawFlags();
-  ID.AddInteger(RawFlags);
-}
-
-static void AddNodeIDFlags(FoldingSetNodeID &ID, const SDNode *N) {
-  AddNodeIDFlags(ID, N->getOpcode(), N->getFlags());
-}
-
 static void AddNodeIDNode(FoldingSetNodeID &ID, unsigned short OpC,
                           SDVTList VTList, ArrayRef<SDValue> OpList) {
   AddNodeIDOpcode(ID, OpC);
@@ -528,8 +512,6 @@ static void AddNodeIDCustom(FoldingSetNodeID &ID, const SDNode *N) {
   }
   } // end switch (N->getOpcode())
 
-  AddNodeIDFlags(ID, N);
-
   // Target specific memory nodes could also have address spaces to check.
   if (N->isTargetMemoryOpcode())
     ID.AddInteger(cast<MemSDNode>(N)->getPointerInfo().getAddrSpace());
@@ -851,6 +833,9 @@ SDNode *SelectionDAG::FindModifiedNodeSlot(SDNode *N, SDValue Op,
   AddNodeIDNode(ID, N->getOpcode(), N->getVTList(), Ops);
   AddNodeIDCustom(ID, N);
   SDNode *Node = FindNodeOrInsertPos(ID, N->getDebugLoc(), InsertPos);
+  if (Node)
+    if (const SDNodeFlags *Flags = N->getFlags())
+      Node->intersectFlagsWith(Flags);
   return Node;
 }
 
@@ -869,6 +854,9 @@ SDNode *SelectionDAG::FindModifiedNodeSlot(SDNode *N,
   AddNodeIDNode(ID, N->getOpcode(), N->getVTList(), Ops);
   AddNodeIDCustom(ID, N);
   SDNode *Node = FindNodeOrInsertPos(ID, N->getDebugLoc(), InsertPos);
+  if (Node)
+    if (const SDNodeFlags *Flags = N->getFlags())
+      Node->intersectFlagsWith(Flags);
   return Node;
 }
 
@@ -886,6 +874,9 @@ SDNode *SelectionDAG::FindModifiedNodeSlot(SDNode *N, ArrayRef<SDValue> Ops,
   AddNodeIDNode(ID, N->getOpcode(), N->getVTList(), Ops);
   AddNodeIDCustom(ID, N);
   SDNode *Node = FindNodeOrInsertPos(ID, N->getDebugLoc(), InsertPos);
+  if (Node)
+    if (const SDNodeFlags *Flags = N->getFlags())
+      Node->intersectFlagsWith(Flags);
   return Node;
 }
 
@@ -3892,10 +3883,12 @@ SDValue SelectionDAG::getNode(unsigned Opcode, SDLoc DL, EVT VT, SDValue N1,
     SDValue Ops[] = {N1, N2};
     FoldingSetNodeID ID;
     AddNodeIDNode(ID, Opcode, VTs, Ops);
-    AddNodeIDFlags(ID, Opcode, Flags);
     void *IP = nullptr;
-    if (SDNode *E = FindNodeOrInsertPos(ID, DL.getDebugLoc(), IP))
+    if (SDNode *E = FindNodeOrInsertPos(ID, DL.getDebugLoc(), IP)) {
+      if (Flags)
+        E->intersectFlagsWith(Flags);
       return SDValue(E, 0);
+    }
 
     N = GetBinarySDNode(Opcode, DL, VTs, N1, N2, Flags);
 
@@ -6249,10 +6242,12 @@ SDNode *SelectionDAG::getNodeIfExists(unsigned Opcode, SDVTList VTList,
   if (VTList.VTs[VTList.NumVTs - 1] != MVT::Glue) {
     FoldingSetNodeID ID;
     AddNodeIDNode(ID, Opcode, VTList, Ops);
-    AddNodeIDFlags(ID, Opcode, Flags);
     void *IP = nullptr;
-    if (SDNode *E = FindNodeOrInsertPos(ID, DebugLoc(), IP))
+    if (SDNode *E = FindNodeOrInsertPos(ID, DebugLoc(), IP)) {
+      if (Flags)
+        E->intersectFlagsWith(Flags);
       return E;
+    }
   }
   return nullptr;
 }
@@ -6948,6 +6943,11 @@ const SDNodeFlags *SDNode::getFlags() const {
   return nullptr;
 }
 
+void SDNode::intersectFlagsWith(const SDNodeFlags *Flags) {
+  if (auto *FlagsNode = dyn_cast<BinaryWithFlagsSDNode>(this))
+    FlagsNode->Flags.intersectWith(Flags);
+}
+
 SDValue SelectionDAG::UnrollVectorOp(SDNode *N, unsigned ResNE) {
   assert(N->getNumValues() == 1 &&
          "Can't unroll a vector with multiple results!");