From d60951f469919476dfae4ca3f5ccb153c7072f47 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault@amd.com>
Date: Wed, 20 Dec 2017 19:11:59 +0000
Subject: [PATCH] DAG: Tolerate non-MemSDNodes for OPC_RecordMemRef

When intrinsics are allowed to have mem operands, there
are two ways this can happen. First is an intrinsic
that is marked has having a mem operand, but is not handled
by getTgtMemIntrinsic.

The second way can occur even for intrinsics which do not
have a mem operand. It seems the selector table does
some kind of sorting based on the opcode, and the
mem ref recording can happen in the same scope for
intrinsics that both do and do not have mem refs.
I haven't been able to figure out exactly why this happens
(although it happens even with the matcher optimizations disabled).
I'm not sure if it's worth trying to avoid hitting this for
these nodes since I think it's still reasonable to handle
this in case getTgtMemIntrinic is not implemented.

llvm-svn: 321208
---
 .../CodeGen/SelectionDAG/SelectionDAGISel.cpp | 32 ++++++++++++++-----
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 18f6997ef83c..d13ccc263718 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -3117,7 +3117,16 @@ void SelectionDAGISel::SelectCodeCommon(SDNode *NodeToMatch,
       continue;
     }
     case OPC_RecordMemRef:
-      MatchedMemRefs.push_back(cast<MemSDNode>(N)->getMemOperand());
+      if (auto *MN = dyn_cast<MemSDNode>(N))
+        MatchedMemRefs.push_back(MN->getMemOperand());
+      else {
+        DEBUG(
+          dbgs() << "Expected MemSDNode ";
+          N->dump(CurDAG);
+          dbgs() << '\n'
+        );
+      }
+
       continue;
 
     case OPC_CaptureGlueInput:
@@ -3563,7 +3572,7 @@ void SelectionDAGISel::SelectCodeCommon(SDNode *NodeToMatch,
         Ops.push_back(InputGlue);
 
       // Create the node.
-      SDNode *Res = nullptr;
+      MachineSDNode *Res = nullptr;
       bool IsMorphNodeTo = Opcode == OPC_MorphNodeTo ||
                      (Opcode >= OPC_MorphNodeTo0 && Opcode <= OPC_MorphNodeTo2);
       if (!IsMorphNodeTo) {
@@ -3589,7 +3598,8 @@ void SelectionDAGISel::SelectCodeCommon(SDNode *NodeToMatch,
                  "Chain node replaced during MorphNode");
           Chain.erase(std::remove(Chain.begin(), Chain.end(), N), Chain.end());
         });
-        Res = MorphNode(NodeToMatch, TargetOpc, VTList, Ops, EmitNodeInfo);
+        Res = cast<MachineSDNode>(MorphNode(NodeToMatch, TargetOpc, VTList,
+                                            Ops, EmitNodeInfo));
       }
 
       // If the node had chain/glue results, update our notion of the current
@@ -3645,13 +3655,19 @@ void SelectionDAGISel::SelectCodeCommon(SDNode *NodeToMatch,
           }
         }
 
-        cast<MachineSDNode>(Res)
-          ->setMemRefs(MemRefs, MemRefs + NumMemRefs);
+        Res->setMemRefs(MemRefs, MemRefs + NumMemRefs);
       }
 
-      DEBUG(dbgs() << "  "
-                   << (IsMorphNodeTo ? "Morphed" : "Created")
-                   << " node: "; Res->dump(CurDAG); dbgs() << "\n");
+      DEBUG(
+        if (!MatchedMemRefs.empty() && Res->memoperands_empty())
+          dbgs() << "  Dropping mem operands\n";
+        dbgs() << "  "
+               << (IsMorphNodeTo ? "Morphed" : "Created")
+               << " node: ";
+        Res->dump(CurDAG);
+
+        dbgs() << '\n';
+      );
 
       // If this was a MorphNodeTo then we're completely done!
       if (IsMorphNodeTo) {
-- 
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