Add additional criteria for hoisting vector.transfer_reads

Non-subview uses of an alloc outside the current loop
can be safely ignored when considering hoisting vector
transfer_reads. This patch adds a condition to check for that
case and updates the unit test accordingly.

Differential Revision: https://reviews.llvm.org/D150469

2 files changed, 4 insertions, 0 deletions

diff --git a/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp b/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp
index 01b893a0e0a5..306762b2da5b 100644
--- a/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp
+++ b/mlir/lib/Dialect/Linalg/Transforms/Hoisting.cpp
@@ -71,6 +71,8 @@ static bool noAliasingUseInLoop(vector::TransferReadOp transferRead,
     }
     if (isMemoryEffectFree(user) || isa<vector::TransferReadOp>(user))
       continue;
+    if (!loop->isAncestor(user))
+      continue;
     return false;
   }
   return true;
diff --git a/mlir/test/Dialect/Linalg/hoisting.mlir b/mlir/test/Dialect/Linalg/hoisting.mlir
index 02b03eeacc30..546b1bb2cd75 100644
--- a/mlir/test/Dialect/Linalg/hoisting.mlir
+++ b/mlir/test/Dialect/Linalg/hoisting.mlir
@@ -696,6 +696,7 @@ transform.sequence failures(propagate) {
 // CHECK:            "some_use"(%[[D0]], %[[D1]], %[[CAST]]) : (vector<32x64xf32>, vector<32x128xf32>, memref<32x128xf32,
 // CHECK-SAME:         strided<[128, 1], offset: ?>>) -> ()
 // CHECK:          }
+// CHECK:          memref.dealloc %[[ALLOC]] : memref<32x64xf32>
 // CHECK:          return
 func.func @hoist_vector_transfer_read() {
   %c0 = arith.constant 0 : index
@@ -710,6 +711,7 @@ func.func @hoist_vector_transfer_read() {
     %3 = vector.transfer_read %memref0[%c0, %c0], %cst_2 {in_bounds = [true, true]} : memref<32x64xf32>, vector<32x64xf32>
     "some_use"(%3, %2, %subview2) : (vector<32x64xf32>, vector<32x128xf32>, memref<32x128xf32, strided<[128, 1], offset: ?>>) -> ()
   }
+  memref.dealloc %memref0 : memref<32x64xf32>
   return
 }