[Mlir-commits] [mlir] Add operands to worklist when only used by deleted op (PR #86990)

[llvmlistbot at llvm.org]

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@@ -688,15 +688,17 @@ void GreedyPatternRewriteDriver::notifyOperationModified(Operation *op) {
   addToWorklist(op);
 }
 
-void GreedyPatternRewriteDriver::addOperandsToWorklist(ValueRange operands) {
-  for (Value operand : operands) {
-    // If the use count of this operand is now < 2, we re-add the defining
-    // operation to the worklist.
-    // TODO: This is based on the fact that zero use operations
-    // may be deleted, and that single use values often have more
-    // canonicalization opportunities.
-    if (!operand || (!operand.use_empty() && !operand.hasOneUse()))
-      continue;
+void GreedyPatternRewriteDriver::addOperandsToWorklist(Operation* op) {
+  for (Value operand : op->getOperands()) {
+    // If this operand was only used by the op under consideration, we re-add
+    // the operation that defined it to the worklist. Indeed, if the op is about
+    // to be deleted and it was the sole user of the operand, the operand may
+    // also be deleted.
+    // TODO: if the operand has a single use besides the op under consideration,
+    // there may be further canonicalization opportunities, so it should be
+    // added to the worklist.
+    if (!operand) continue;
+    if (!llvm::all_of(operand.getUsers(), [&op](auto u) { return u == op; })) continue;
----------------
mlevesquedion wrote:

Actually, nevermind. I thought `mlir::Value` had `hasOneUser`, but that's `llvm::Value`. I believe there would be a more efficient way to do this (https://github.com/llvm/llvm-project/blob/44af53b22aaa1fe382b22329bbc7e4610ecbacc8/llvm/lib/IR/Value.cpp#L157), but the users list doesn't seem to be deduped, so just doing `std::next(user_begin()) == user_end()` does not work.

https://github.com/llvm/llvm-project/pull/86990