[SelectionDAG] Consolidate (t|T)ransferDbgValues methods, NFC.

TransferDbgValues (capital 'T') is wired into ReplaceAllUsesWith, and
transferDbgValues (lowercase 't') is used elsewhere (e.g in Legalize).

Both functions should be doing the exact same thing. This patch
consolidates the logic into one place.

Differential Revision: https://reviews.llvm.org/D40104

llvm-svn: 318448

2 files changed, 30 insertions, 39 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
index 053d562a244..73e29969a21 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
@@ -845,13 +845,14 @@ void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo,
   AnalyzeNewValue(Lo);
   AnalyzeNewValue(Hi);
 
-  // Transfer debug values.
+  // Transfer debug values. Don't invalidate the source debug value until it's
+  // been transferred to the high and low bits.
   if (DAG.getDataLayout().isBigEndian()) {
-    DAG.transferDbgValues(Op, Hi, 0, Hi.getValueSizeInBits());
+    DAG.transferDbgValues(Op, Hi, 0, Hi.getValueSizeInBits(), false);
     DAG.transferDbgValues(Op, Lo, Hi.getValueSizeInBits(),
                           Lo.getValueSizeInBits());
   } else {
-    DAG.transferDbgValues(Op, Lo, 0, Lo.getValueSizeInBits());
+    DAG.transferDbgValues(Op, Lo, 0, Lo.getValueSizeInBits(), false);
     DAG.transferDbgValues(Op, Hi, Lo.getValueSizeInBits(),
                           Hi.getValueSizeInBits());
   }
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 1ed982d6bac..e3d136a378e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -7027,16 +7027,29 @@ SDDbgValue *SelectionDAG::getFrameIndexDbgValue(DIVariable *Var,
 }
 
 void SelectionDAG::transferDbgValues(SDValue From, SDValue To,
-                                     unsigned OffsetInBits,
-                                     unsigned SizeInBits) {
+                                     unsigned OffsetInBits, unsigned SizeInBits,
+                                     bool InvalidateDbg) {
   SDNode *FromNode = From.getNode();
   SDNode *ToNode = To.getNode();
-  assert(FromNode != ToNode);
+  assert(FromNode && ToNode && "Can't modify dbg values");
+
+  // Remove these checks when ReplaceAllUsesWith gets stricter.
+  // TODO: assert(From != To && "Redundant dbg value transfer");
+  // TODO: assert(FromNode != ToNode && "Intranode dbg value transfer");
+  if (From == To || FromNode == ToNode)
+    return;
+
+  if (!FromNode->getHasDebugValue())
+    return;
 
   SmallVector<SDDbgValue *, 2> ClonedDVs;
   for (SDDbgValue *Dbg : GetDbgValues(FromNode)) {
-    if (Dbg->getKind() != SDDbgValue::SDNODE)
-      break;
+    // Just transfer the dbg value attached to From.
+    if (Dbg->getResNo() != From.getResNo())
+      continue;
+
+    assert(!Dbg->isInvalidated() && "Invalid dbg value");
+    assert(Dbg->getKind() == SDDbgValue::SDNODE && "Can't transfer dbg value");
 
     DIVariable *Var = Dbg->getVariable();
     auto *Expr = Dbg->getExpression();
@@ -7059,7 +7072,9 @@ void SelectionDAG::transferDbgValues(SDValue From, SDValue To,
         getDbgValue(Var, Expr, ToNode, To.getResNo(), Dbg->isIndirect(),
                     Dbg->getDebugLoc(), Dbg->getOrder());
     ClonedDVs.push_back(Clone);
-    Dbg->setIsInvalidated();
+
+    if (InvalidateDbg)
+      Dbg->setIsInvalidated();
   }
 
   for (SDDbgValue *Dbg : ClonedDVs)
@@ -7137,7 +7152,7 @@ void SelectionDAG::ReplaceAllUsesWith(SDValue FromN, SDValue To) {
   assert(From != To.getNode() && "Cannot replace uses of with self");
 
   // Preserve Debug Values
-  TransferDbgValues(FromN, To);
+  transferDbgValues(FromN, To);
 
   // Iterate over all the existing uses of From. New uses will be added
   // to the beginning of the use list, which we avoid visiting.
@@ -7196,7 +7211,7 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To) {
   for (unsigned i = 0, e = From->getNumValues(); i != e; ++i)
     if (From->hasAnyUseOfValue(i)) {
       assert((i < To->getNumValues()) && "Invalid To location");
-      TransferDbgValues(SDValue(From, i), SDValue(To, i));
+      transferDbgValues(SDValue(From, i), SDValue(To, i));
     }
 
   // Iterate over just the existing users of From. See the comments in
@@ -7240,7 +7255,7 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From, const SDValue *To) {
 
   // Preserve Debug Info.
   for (unsigned i = 0, e = From->getNumValues(); i != e; ++i)
-    TransferDbgValues(SDValue(From, i), *To);
+    transferDbgValues(SDValue(From, i), *To);
 
   // Iterate over just the existing users of From. See the comments in
   // the ReplaceAllUsesWith above.
@@ -7287,7 +7302,7 @@ void SelectionDAG::ReplaceAllUsesOfValueWith(SDValue From, SDValue To){
   }
 
   // Preserve Debug Info.
-  TransferDbgValues(From, To);
+  transferDbgValues(From, To);
 
   // Iterate over just the existing users of From. See the comments in
   // the ReplaceAllUsesWith above.
@@ -7365,7 +7380,7 @@ void SelectionDAG::ReplaceAllUsesOfValuesWith(const SDValue *From,
   if (Num == 1)
     return ReplaceAllUsesOfValueWith(*From, *To);
 
-  TransferDbgValues(*From, *To);
+  transferDbgValues(*From, *To);
 
   // Read up all the uses and make records of them. This helps
   // processing new uses that are introduced during the
@@ -7514,31 +7529,6 @@ void SelectionDAG::AddDbgValue(SDDbgValue *DB, SDNode *SD, bool isParameter) {
   DbgInfo->add(DB, SD, isParameter);
 }
 
-/// Transfer SDDbgValues. Called in replace nodes.
-void SelectionDAG::TransferDbgValues(SDValue From, SDValue To) {
-  if (From == To || !From.getNode()->getHasDebugValue())
-    return;
-  SDNode *FromNode = From.getNode();
-  SDNode *ToNode = To.getNode();
-  SmallVector<SDDbgValue *, 2> ClonedDVs;
-  for (auto *Dbg : GetDbgValues(FromNode)) {
-    // Only add Dbgvalues attached to same ResNo.
-    if (Dbg->getKind() == SDDbgValue::SDNODE &&
-        Dbg->getSDNode() == From.getNode() &&
-        Dbg->getResNo() == From.getResNo() && !Dbg->isInvalidated()) {
-      assert(FromNode != ToNode &&
-             "Should not transfer Debug Values intranode");
-      SDDbgValue *Clone = getDbgValue(Dbg->getVariable(), Dbg->getExpression(),
-                                      ToNode, To.getResNo(), Dbg->isIndirect(),
-                                      Dbg->getDebugLoc(), Dbg->getOrder());
-      ClonedDVs.push_back(Clone);
-      Dbg->setIsInvalidated();
-    }
-  }
-  for (SDDbgValue *I : ClonedDVs)
-    AddDbgValue(I, ToNode, false);
-}
-
 SDValue SelectionDAG::makeEquivalentMemoryOrdering(LoadSDNode *OldLoad,
                                                    SDValue NewMemOp) {
   assert(isa<MemSDNode>(NewMemOp.getNode()) && "Expected a memop node");