[Mlir-commits] [mlir] [mlir][bufferization] Add `BufferizableOpInterface::hasTensorSemantics` (PR #75273)

Matthias Springer llvmlistbot at llvm.org
Tue Dec 12 18:19:01 PST 2023


https://github.com/matthias-springer created https://github.com/llvm/llvm-project/pull/75273

Add a new interface method to `BufferizableOpInterface`: `hasTensorSemanticsForBufferization`. This method returns "true" if the op has tensor semantics and should be bufferized.

Until now, we assumed that an op has tensor semantics if it has tensor operands and/or tensor op results. However, there are ops like `ml_program.global` that do not have any results/operands but must still be bufferized (#75103). The new interface method can return "true" for such ops.

This change also decouples `bufferization::bufferizeOp` a bit from the func dialect.

>From 7ed95b12fd3909de88a84fb6e9f9c5b050546902 Mon Sep 17 00:00:00 2001
From: Matthias Springer <springerm at google.com>
Date: Wed, 13 Dec 2023 11:16:29 +0900
Subject: [PATCH] [mlir][bufferization] Add
 `BufferizableOpInterface::hasTensorSemantics`

Add a new interface method to `BufferizableOpInterface`: `hasTensorSemanticsForBufferization`. This method returns "true" if the op has tensor semantics and should be bufferized.

Until now, we assumed that an op has tensor semantics if it has tensor operands and/or tensor op results. However, there are ops like `ml_program.global` that do not have any results/operands but must still be bufferized (#75103). The new interface method can return "true" for such ops.

This change also decouples `bufferization::bufferizeOp` a bit from the func dialect.
---
 .../IR/BufferizableOpInterface.h              | 10 ++++++
 .../IR/BufferizableOpInterface.td             | 22 +++++++++++++
 .../IR/BufferizableOpInterface.cpp            | 25 ++++++++++++++
 .../Bufferization/Transforms/Bufferize.cpp    | 33 +++----------------
 .../FuncBufferizableOpInterfaceImpl.cpp       | 22 +++++++++++++
 .../Transforms/OneShotModuleBufferize.cpp     |  9 +++++
 6 files changed, 92 insertions(+), 29 deletions(-)

diff --git a/mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h b/mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h
index 7c09a43f96397..d3dc5683772e2 100644
--- a/mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h
+++ b/mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h
@@ -601,6 +601,12 @@ FailureOr<BaseMemRefType> getBufferType(Value value,
                                         const BufferizationOptions &options,
                                         SmallVector<Value> &invocationStack);
 
+/// Return "true" if the given op has tensor semantics and should be bufferized.
+/// If the op is bufferizable, the BufferizableOpInterface is queried.
+/// Otherwise, an op has tensor semantics if it has tensor operands, tensor
+/// op results and/or tensor block arguments.
+bool hasTensorSemanticsForBufferization(Operation *op);
+
 /// Replace an op with replacement values. The op is deleted. Tensor OpResults
 /// must be replaced with memref values.
 void replaceOpWithBufferizedValues(RewriterBase &rewriter, Operation *op,
@@ -694,6 +700,10 @@ AliasingOpOperandList unknownGetAliasingOpOperands(Value value);
 /// This is the default implementation of getAliasingValues in case the owner
 /// op does not implement the BufferizableOpInterface.
 AliasingValueList unknownGetAliasingValues(OpOperand &opOperand);
+
+/// This is the default implementation of
+/// BufferizableOpInterface::hasTensorSemanticsForBufferization.
+bool defaultHasTensorSemanticsForBufferization(Operation *op);
 } // namespace detail
 
 } // namespace bufferization
diff --git a/mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.td b/mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.td
index fd1ceb68af5dd..e7445cb4e63da 100644
--- a/mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.td
+++ b/mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.td
@@ -575,6 +575,28 @@ def BufferizableOpInterface : OpInterface<"BufferizableOpInterface"> {
           return false;
         }]
       >,
+      InterfaceMethod<
+        /*desc=*/[{
+          Return "true" if the this op has tensor semantics and should be
+          bufferized. By default, ops with tensor operands, tensor op results
+          and/or tensor block arguments have tensor semantics.
+
+          This interface methods can be implemented by ops that should be
+          bufferized but do not have tensor semantics according to the above
+          definition. E.g., this function can return "true" for symbols.
+
+          TODO: This interface method should be called `hasTensorSemantics`, but
+          that name is already in use in `DestinationStyleOpInterface`.
+        }],
+        /*retType=*/"bool",
+        /*methodName=*/"hasTensorSemanticsForBufferization",
+        /*args=*/(ins),
+        /*methodBody=*/"",
+        /*defaultImplementation=*/[{
+          return ::mlir::bufferization::detail
+              ::defaultHasTensorSemanticsForBufferization($_op.getOperation());
+        }]
+      >,
       StaticInterfaceMethod<
         /*desc=*/[{
           Return `true` if the op and this interface implementation supports
diff --git a/mlir/lib/Dialect/Bufferization/IR/BufferizableOpInterface.cpp b/mlir/lib/Dialect/Bufferization/IR/BufferizableOpInterface.cpp
index 1e8dc4387ed4f..8f577947f8ddb 100644
--- a/mlir/lib/Dialect/Bufferization/IR/BufferizableOpInterface.cpp
+++ b/mlir/lib/Dialect/Bufferization/IR/BufferizableOpInterface.cpp
@@ -689,6 +689,12 @@ bufferization::getBufferType(Value value, const BufferizationOptions &options,
                        *options.defaultMemorySpace);
 }
 
+bool bufferization::hasTensorSemanticsForBufferization(Operation *op) {
+  if (auto bufferizableOp = dyn_cast<BufferizableOpInterface>(op))
+    return bufferizableOp.hasTensorSemanticsForBufferization();
+  return detail::defaultHasTensorSemanticsForBufferization(op);
+}
+
 void bufferization::replaceOpWithBufferizedValues(RewriterBase &rewriter,
                                                   Operation *op,
                                                   ValueRange values) {
@@ -989,3 +995,22 @@ bufferization::detail::unknownGetAliasingValues(OpOperand &opOperand) {
           r.addAlias({bbArg, BufferRelation::Unknown, /*isDefinite=*/false});
   return r;
 }
+
+static bool isaTensor(Type t) { return isa<TensorType>(t); }
+
+bool bufferization::detail::defaultHasTensorSemanticsForBufferization(
+    Operation *op) {
+  bool hasTensorBlockArgument = any_of(op->getRegions(), [](Region &r) {
+    return any_of(r.getBlocks(), [](Block &b) {
+      return any_of(b.getArguments(), [](BlockArgument bbArg) {
+        return isaTensor(bbArg.getType());
+      });
+    });
+  });
+  if (hasTensorBlockArgument)
+    return true;
+
+  bool hasTensorResult = any_of(op->getResultTypes(), isaTensor);
+  bool hasTensorOperand = any_of(op->getOperandTypes(), isaTensor);
+  return hasTensorResult || hasTensorOperand;
+}
diff --git a/mlir/lib/Dialect/Bufferization/Transforms/Bufferize.cpp b/mlir/lib/Dialect/Bufferization/Transforms/Bufferize.cpp
index f2125feeda541..79be7bed79db3 100644
--- a/mlir/lib/Dialect/Bufferization/Transforms/Bufferize.cpp
+++ b/mlir/lib/Dialect/Bufferization/Transforms/Bufferize.cpp
@@ -350,31 +350,6 @@ mlir::bufferization::createFinalizingBufferizePass() {
 // BufferizableOpInterface-based Bufferization
 //===----------------------------------------------------------------------===//
 
-static bool isaTensor(Type t) { return isa<TensorType>(t); }
-
-/// Return true if the given op has a tensor result or a tensor operand.
-static bool hasTensorSemantics(Operation *op) {
-  bool hasTensorBlockArgument = any_of(op->getRegions(), [](Region &r) {
-    return any_of(r.getBlocks(), [](Block &b) {
-      return any_of(b.getArguments(), [](BlockArgument bbArg) {
-        return isaTensor(bbArg.getType());
-      });
-    });
-  });
-  if (hasTensorBlockArgument)
-    return true;
-
-  if (auto funcOp = dyn_cast<FunctionOpInterface>(op)) {
-    bool hasTensorArg = any_of(funcOp.getArgumentTypes(), isaTensor);
-    bool hasTensorResult = any_of(funcOp.getResultTypes(), isaTensor);
-    return hasTensorArg || hasTensorResult;
-  }
-
-  bool hasTensorResult = any_of(op->getResultTypes(), isaTensor);
-  bool hasTensorOperand = any_of(op->getOperandTypes(), isaTensor);
-  return hasTensorResult || hasTensorOperand;
-}
-
 namespace {
 /// A rewriter that keeps track of extra information during bufferization.
 class BufferizationRewriter : public IRRewriter, public RewriterBase::Listener {
@@ -417,7 +392,7 @@ class BufferizationRewriter : public IRRewriter, public RewriterBase::Listener {
       return;
 
     // Skip non-tensor ops.
-    if (!hasTensorSemantics(op))
+    if (!hasTensorSemanticsForBufferization(op))
       return;
 
     // Skip ops that are not allowed to be bufferized.
@@ -470,7 +445,7 @@ LogicalResult bufferization::bufferizeOp(Operation *op,
   // canonicalize away (or canonicalize to more precise layouts).
   SmallVector<Operation *> worklist;
   op->walk<WalkOrder::PostOrder>([&](Operation *op) {
-    if (hasTensorSemantics(op))
+    if (hasTensorSemanticsForBufferization(op))
       worklist.push_back(op);
   });
 
@@ -492,7 +467,7 @@ LogicalResult bufferization::bufferizeOp(Operation *op,
     if (!options.isOpAllowed(nextOp))
       continue;
     // Skip ops that no longer have tensor semantics.
-    if (!hasTensorSemantics(nextOp))
+    if (!hasTensorSemanticsForBufferization(nextOp))
       continue;
     // Check for unsupported unstructured control flow.
     if (!bufferizableOp.supportsUnstructuredControlFlow())
@@ -546,7 +521,7 @@ LogicalResult bufferization::bufferizeOp(Operation *op,
       continue;
     // Ops that no longer have tensor semantics (because they were updated
     // in-place) are allowed.
-    if (!hasTensorSemantics(op))
+    if (!hasTensorSemanticsForBufferization(op))
       continue;
     // Continue ops that are not allowed.
     if (!options.isOpAllowed(op))
diff --git a/mlir/lib/Dialect/Bufferization/Transforms/FuncBufferizableOpInterfaceImpl.cpp b/mlir/lib/Dialect/Bufferization/Transforms/FuncBufferizableOpInterfaceImpl.cpp
index 3a8c397c02a80..5aab035f9f30f 100644
--- a/mlir/lib/Dialect/Bufferization/Transforms/FuncBufferizableOpInterfaceImpl.cpp
+++ b/mlir/lib/Dialect/Bufferization/Transforms/FuncBufferizableOpInterfaceImpl.cpp
@@ -325,6 +325,28 @@ struct FuncOpInterface
 
   static bool supportsUnstructuredControlFlow() { return true; }
 
+  bool hasTensorSemanticsForBufferization(Operation *op) const {
+    auto isaTensor = [](Type type) { return isa<TensorType>(type); };
+
+    // A function has tensor semantics if it has tensor arguments/results.
+    auto funcOp = cast<FuncOp>(op);
+    bool hasTensorArg = any_of(funcOp.getArgumentTypes(), isaTensor);
+    bool hasTensorResult = any_of(funcOp.getResultTypes(), isaTensor);
+    if (hasTensorArg || hasTensorResult)
+      return true;
+
+    // It also has tensor semantics if it has tensor block arguments.
+    // TODO: Decouple bufferization of unstructured control flow from
+    // BufferizableOpInterface implementations. We should only care about
+    // region entry block arguments here (which are already covered by the
+    // argument types of the function).
+    for (Block &block : funcOp.getBody())
+      if (any_of(block.getArgumentTypes(), isaTensor))
+        return true;
+
+    return false;
+  }
+
   AliasingOpOperandList
   getAliasingOpOperands(Operation *op, Value value,
                         const AnalysisState &state) const {
diff --git a/mlir/lib/Dialect/Bufferization/Transforms/OneShotModuleBufferize.cpp b/mlir/lib/Dialect/Bufferization/Transforms/OneShotModuleBufferize.cpp
index 1404ed8f43f96..aeda995fd585a 100644
--- a/mlir/lib/Dialect/Bufferization/Transforms/OneShotModuleBufferize.cpp
+++ b/mlir/lib/Dialect/Bufferization/Transforms/OneShotModuleBufferize.cpp
@@ -458,6 +458,15 @@ LogicalResult mlir::bufferization::bufferizeModuleOp(
       foldMemRefCasts(funcOp);
   }
 
+  // Bufferize all other ops.
+  for (Operation &op : moduleOp.getOps()) {
+    // Functions were already bufferized.
+    if (isa<func::FuncOp>(&op))
+      continue;
+    if (failed(bufferizeOp(&op, options, statistics)))
+      return failure();
+  }
+
   // Post-pass cleanup of function argument attributes.
   removeBufferizationAttributesInModule(moduleOp);
 



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