ISel type legalizer: debug messages. NFC.

Minor addition and follow up of r314773 and r311533: this adds more
debug messages to the type legalizer. For each node, it dumps
legalization info for results and operands nodes, rather than just the
final legalized node.

Differential Revision: https://reviews.llvm.org/D38726

llvm-svn: 315904

2 files changed, 17 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index 75fec7bd1d4..68cac22a99e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -40,8 +40,10 @@ void DAGTypeLegalizer::PromoteIntegerResult(SDNode *N, unsigned ResNo) {
   SDValue Res = SDValue();
 
   // See if the target wants to custom expand this node.
-  if (CustomLowerNode(N, N->getValueType(ResNo), true))
+  if (CustomLowerNode(N, N->getValueType(ResNo), true)) {
+    DEBUG(dbgs() << "Node has been custom expanded, done\n");
     return;
+  }
 
   switch (N->getOpcode()) {
   default:
@@ -885,8 +887,10 @@ bool DAGTypeLegalizer::PromoteIntegerOperand(SDNode *N, unsigned OpNo) {
   DEBUG(dbgs() << "Promote integer operand: "; N->dump(&DAG); dbgs() << "\n");
   SDValue Res = SDValue();
 
-  if (CustomLowerNode(N, N->getOperand(OpNo).getValueType(), false))
+  if (CustomLowerNode(N, N->getOperand(OpNo).getValueType(), false)) {
+    DEBUG(dbgs() << "Node has been custom lowered, done\n");
     return false;
+  }
 
   switch (N->getOpcode()) {
     default:
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
index f331fc7c250..b42edf8e751 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
@@ -226,15 +226,21 @@ bool DAGTypeLegalizer::run() {
     assert(N->getNodeId() == ReadyToProcess &&
            "Node should be ready if on worklist!");
 
-    if (IgnoreNodeResults(N))
+    DEBUG(dbgs() << "Legalizing node: "; N->dump());
+    if (IgnoreNodeResults(N)) {
+      DEBUG(dbgs() << "Ignoring node results\n");
       goto ScanOperands;
+    }
 
     // Scan the values produced by the node, checking to see if any result
     // types are illegal.
     for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
       EVT ResultVT = N->getValueType(i);
+      DEBUG(dbgs() << "Analyzing result type: " <<
+                      ResultVT.getEVTString() << "\n");
       switch (getTypeAction(ResultVT)) {
       case TargetLowering::TypeLegal:
+        DEBUG(dbgs() << "Legal result type\n");
         break;
       // The following calls must take care of *all* of the node's results,
       // not just the illegal result they were passed (this includes results
@@ -291,9 +297,12 @@ ScanOperands:
       if (IgnoreNodeResults(N->getOperand(i).getNode()))
         continue;
 
-      EVT OpVT = N->getOperand(i).getValueType();
+      const auto Op = N->getOperand(i);
+      DEBUG(dbgs() << "Analyzing operand: "; Op.dump());
+      EVT OpVT = Op.getValueType();
       switch (getTypeAction(OpVT)) {
       case TargetLowering::TypeLegal:
+        DEBUG(dbgs() << "Legal operand\n");
         continue;
       // The following calls must either replace all of the node's results
       // using ReplaceValueWith, and return "false"; or update the node's