Drain MTE before tnotify

docs/PTO_IR_manual.md

@@ -9370,6 +9370,7 @@ pto.comm.tget(%dst, %src, buf(%ping, %pong) : !pto.partition_tensor_view<128xf32
 
 - `signal` must be a GM-shaped value with element type `i32`.
 - `value` / `cmpValue` must be signless integer scalars.
+- `pto.comm.tnotify` lowering emits `pipe_barrier(PIPE_ALL)` before `pto::comm::TNOTIFY(...)` so prior MTE-side loads and stores are drained before the signal write.
 
 **Examples:**
 

lib/PTO/Transforms/PTOToEmitC.cpp

@@ -6387,6 +6387,15 @@ static std::string notifyOpTok(pto::NotifyOp op) {
   return "pto::comm::NotifyOp::Set";
 }
 
+static void emitPipeBarrierAll(ConversionPatternRewriter &rewriter,
+                               Location loc) {
+  auto *ctx = rewriter.getContext();
+  auto args =
+      rewriter.getArrayAttr({emitc::OpaqueAttr::get(ctx, "PIPE_ALL")});
+  rewriter.create<emitc::CallOpaqueOp>(loc, TypeRange{}, "pipe_barrier", args,
+                                       ArrayAttr{}, ValueRange{});
+}
+
 static std::string waitCmpTok(pto::WaitCmp cmp) {
   switch (cmp) {
   case pto::WaitCmp::EQ:
@@ -6641,6 +6650,8 @@ struct PTOSignalCommToEmitC : public OpConversionPattern<SignalOp> {
           rewriter, op.getLoc(), notifyTy, notifyOpTok(op.getNotifyOp()));
       SmallVector<Value> operands{*signalGT, peelUnrealized(adaptor.getValue()),
                                   notifyOp};
+      // TNOTIFY writes the signal on the scalar pipe; drain prior MTE work first.
+      emitPipeBarrierAll(rewriter, op.getLoc());
       rewriter.create<emitc::CallOpaqueOp>(op.getLoc(), TypeRange{}, callee,
                                            ArrayAttr{}, ArrayAttr{}, operands);
       rewriter.eraseOp(op);

test/lit/pto/issue711_tnotify_mte_drain.pto

@@ -0,0 +1,57 @@
+// Copyright (c) 2026 Huawei Technologies Co., Ltd.
+// This program is free software, you can redistribute it and/or modify it under the terms and conditions of
+// CANN Open Software License Agreement Version 2.0 (the "License").
+// Please refer to the License for details. You may not use this file except in compliance with the License.
+// THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE.
+// See LICENSE in the root of the software repository for the full text of the License.
+
+// RUN: ptoas --pto-arch=a3 %s -o - 2>&1 | FileCheck %s
+
+module {
+  func.func @tnotify_drains_mte_before_signal(
+      %src_ptr: !pto.ptr<f32>,
+      %dst_ptr: !pto.ptr<f32>,
+      %signal_ptr: !pto.ptr<i32>)
+      attributes {pto.kernel_kind = #pto.kernel_kind<vector>} {
+    %c0 = arith.constant 0 : index
+    %c1 = arith.constant 1 : index
+    %c32 = arith.constant 32 : index
+    %c1_i32 = arith.constant 1 : i32
+
+    %tile = pto.alloc_tile :
+      !pto.tile_buf<loc=vec, dtype=f32, rows=1, cols=32, v_row=1, v_col=32, blayout=row_major, slayout=none_box, fractal=512, pad=0>
+
+    %src_view = pto.make_tensor_view %src_ptr,
+      shape = [%c1, %c32], strides = [%c32, %c1] : !pto.tensor_view<?x?xf32>
+    %src = pto.partition_view %src_view,
+      offsets = [%c0, %c0], sizes = [%c1, %c32]
+      : !pto.tensor_view<?x?xf32> -> !pto.partition_tensor_view<1x32xf32>
+
+    %dst_view = pto.make_tensor_view %dst_ptr,
+      shape = [%c1, %c32], strides = [%c32, %c1] : !pto.tensor_view<?x?xf32>
+    %dst = pto.partition_view %dst_view,
+      offsets = [%c0, %c0], sizes = [%c1, %c32]
+      : !pto.tensor_view<?x?xf32> -> !pto.partition_tensor_view<1x32xf32>
+
+    pto.tload ins(%src : !pto.partition_tensor_view<1x32xf32>)
+              outs(%tile : !pto.tile_buf<loc=vec, dtype=f32, rows=1, cols=32, v_row=1, v_col=32, blayout=row_major, slayout=none_box, fractal=512, pad=0>)
+    pto.tstore ins(%tile : !pto.tile_buf<loc=vec, dtype=f32, rows=1, cols=32, v_row=1, v_col=32, blayout=row_major, slayout=none_box, fractal=512, pad=0>)
+               outs(%dst : !pto.partition_tensor_view<1x32xf32>)
+
+    %signal_view = pto.make_tensor_view %signal_ptr,
+      shape = [%c1], strides = [%c1] : !pto.tensor_view<1xi32>
+    %signal = pto.partition_view %signal_view,
+      offsets = [%c0], sizes = [%c1]
+      : !pto.tensor_view<1xi32> -> !pto.partition_tensor_view<1xi32>
+    pto.comm.tnotify(%signal, %c1_i32 : !pto.partition_tensor_view<1xi32>, i32)
+        {notifyOp = #pto<notify_op set>}
+    return
+  }
+}
+
+// CHECK-LABEL: AICORE void tnotify_drains_mte_before_signal(
+// CHECK: TLOAD(
+// CHECK: TSTORE(
+// CHECK: pipe_barrier(PIPE_ALL);
+// CHECK-NEXT: pto::comm::TNOTIFY(