[MLIR] Emit debug message if inlining fails

[jurahul]

Summary

Emit a debug message if inlining fails.

[jurahul]

Fix space

[jpienaar]

mlir/lib/Transforms/Inliner.cpp

438

Did you mean to have the dump inside the LLVM_DEBUG section too?

[jurahul]

Move call.dump() inside LLVM_DEBUG

mlir/lib/Transforms/Inliner.cpp

438

Yes, I did.

[mehdi_amini]

mlir/lib/Transforms/Inliner.cpp

438

Why the **?

Also you can avoid the dump and just write it like this I think: LLVM_DEBUG(llvm::dbgs() << "Failed to inline: " << call << "\n");

[jurahul]

mlir/lib/Transforms/Inliner.cpp

438

The "**" is there to indicate that the message is in the scope of the earlier message, so it will appear as:

* Inlining call: ...
** Failed to inline: ...

I am ok if we want just a single '*'. Also llvm::dbgs() << call does not work, I guess the insertion operator << has not been overloaded for CallOpInterface (or its parent). I will check what would be needed to get that working.

[jpienaar]

mlir/lib/Transforms/Inliner.cpp

438

You should be able to do LLVM_DEBUG(call.print(llvm::dbgs() << " ..."); llvm::dbgs() << '\n');

[jurahul]

• Allow MLIR op's to be printed using <<

[rriddle]

mlir/include/mlir/IR/OpDefinition.h

263

nit: Please use complete sentences in comments.

[jurahul]

Address River's comment

[jurahul]

mlir/lib/Transforms/Inliner.cpp

438

I have overloaded the << operator now, so its much cleaner.

[rriddle]

mlir/lib/Transforms/Inliner.cpp

437

Why stream in the call here? It is already being streamed in above, this just duplicates it.

[jurahul]

Don't stream call

[mehdi_amini]

mlir/lib/Transforms/Inliner.cpp

438

Thanks, LG.

mlir/include/mlir/IR/OpDefinition.h

inline bool operator!=(OpState lhs, OpState rhs) {
   return lhs.getOperation() != rhs.getOperation();
 }
 
 /// This class represents a single result from folding an operation.
 class OpFoldResult : public PointerUnion<Attribute, Value> {
   using PointerUnion<Attribute, Value>::PointerUnion;
 };
 
+/// Allow printing to a stream
+inline raw_ostream &operator<<(raw_ostream &os, OpState &op) {
+  op.print(os, OpPrintingFlags().useLocalScope());
+  return os;
+}
+
 /// This template defines the foldHook as used by AbstractOperation.
 ///
 /// The default implementation uses a general fold method that can be defined on
 /// custom ops which can return multiple results.
 template <typename ConcreteType, bool isSingleResult, typename = void>
 class FoldingHook {
 public:
   /// This is an implementation detail of the constant folder hook for

mlir/lib/Transforms/Inliner.cpp

inlineCallsInSCC(Inliner &inliner, CGUseList &useList,
   SmallVector<CallGraphNode *, 1> deadNodes;
 
   // Try to inline each of the call operations. Don't cache the end iterator
   // here as more calls may be added during inlining.
   bool inlinedAnyCalls = false;
   for (unsigned i = 0; i != calls.size(); ++i) {
     ResolvedCall it = calls[i];
     bool doInline = shouldInline(it);
+    CallOpInterface call = it.call;
     LLVM_DEBUG({
       if (doInline)
-        llvm::dbgs() << "* Inlining call: ";
+        llvm::dbgs() << "* Inlining call: " << call << "\n";
       else
-        llvm::dbgs() << "* Not inlining call: ";
-      it.call.dump();
+        llvm::dbgs() << "* Not inlining call: " << call << "\n";
     });
     if (!doInline)
       continue;
-    CallOpInterface call = it.call;
     Region *targetRegion = it.targetNode->getCallableRegion();
 
     // If this is the last call to the target node and the node is discardable,
     // then inline it in-place and delete the node if successful.
     bool inlineInPlace = useList.hasOneUseAndDiscardable(it.targetNode);
 
     LogicalResult inlineResult = inlineCall(
         inliner, call, cast<CallableOpInterface>(targetRegion->getParentOp()),
         targetRegion, /*shouldCloneInlinedRegion=*/!inlineInPlace);
-    if (failed(inlineResult))
+    if (failed(inlineResult)) {
+      LLVM_DEBUG(llvm::dbgs() << "** Failed to inline: " << call << "\n");
       continue;
+    }
     inlinedAnyCalls = true;
 
     // If the inlining was successful, Merge the new uses into the source node.
     useList.dropCallUses(it.sourceNode, call.getOperation(), cg);
     useList.mergeUsesAfterInlining(it.targetNode, it.sourceNode);
 
     // then erase the call.
     call.erase();