[Mlir-commits] [mlir] [MLIR][Affine] Fix fusion across ops with unknown memory effects (PR #203231)

[Federico Bruzzone]

================
@@ -38,6 +38,45 @@ using llvm::SmallDenseMap;
 
 using Node = MemRefDependenceGraph::Node;
 
+/// Returns the values that `op` may have a memref effect of type `EffectTys`
+/// on, not considering recursive effects. An op with unknown memory effects
+/// (e.g. a call to an external function without a memory-effect interface) is
+/// conservatively assumed to affect all its memref operands.
+template <typename... EffectTys>
+static void getMayEffectedValues(Operation *op,
+                                 SmallVectorImpl<Value> &values) {
+  auto memOp = dyn_cast<MemoryEffectOpInterface>(op);
+  if (!memOp) {
+    if (op->hasTrait<OpTrait::HasRecursiveMemoryEffects>())
+      // No effects.
+      return;
+    // Memref operands have to be considered as being affected.
+    for (Value operand : op->getOperands()) {
+      if (isa<MemRefType>(operand.getType()))
+        values.push_back(operand);
+    }
+    return;
+  }
+  SmallVector<SideEffects::EffectInstance<MemoryEffects::Effect>, 4> effects;
+  memOp.getEffects(effects);
+  for (auto &effect : effects) {
+    Value effectVal = effect.getValue();
+    if (isa<EffectTys...>(effect.getEffect()) && effectVal &&
+        isa<MemRefType>(effectVal.getType()))
+      values.push_back(effectVal);
+  };
+}
+
+/// Returns true if `op` may have a memory effect of type `EffectTys` on
+/// `memref`, i.e., whether `memref` is among the values returned by
+/// `getMayEffectedValues` for `op`.
+template <typename... EffectTys>
+static bool mayHaveEffect(Operation *op, Value memref) {
+  SmallVector<Value> values;
+  getMayEffectedValues<EffectTys...>(op, values);
+  return llvm::is_contained(values, memref);
+}
+
----------------
FedericoBruzzone wrote:

Couldn't we avoid recalculating this thing? I think, yes :D




https://github.com/llvm/llvm-project/pull/203231