[Mlir-commits] [mlir] [mlir][bufferization] Add tests for OptimizeAllocationLiveness edge cases (PR #189505)
Mohamed Deraz Nasr
llvmlistbot at llvm.org
Mon Mar 30 20:16:42 PDT 2026
https://github.com/MDerazNasr updated https://github.com/llvm/llvm-project/pull/189505
>From 5ae7f82d55027043a37a0236e94b1f25f1003df7 Mon Sep 17 00:00:00 2001
From: Mohamed Deraz Nasr <mderaznasr at gmail.com>
Date: Mon, 30 Mar 2026 19:22:52 -0400
Subject: [PATCH 1/2] [mlir][bufferization] Add tests for
OptimizeAllocationLiveness edge cases
Add two test cases to optimize-allocation-liveness.mlir that cover
untested code paths in OptimizeAllocationLiveness.cpp:
1. An alloc with no users other than its dealloc. The pass hits the
lastUser == nullptr branch and leaves the IR unchanged.
2. An alloc with a dynamic dimension (memref<?xf32>). All existing
tests use static shapes. This verifies the pass moves the dealloc
to right after the last user when the alloc size is not known at
compile time.
---
.../optimize-allocation-liveness.mlir | 44 +++++++++++++++++++
1 file changed, 44 insertions(+)
diff --git a/mlir/test/Dialect/Bufferization/Transforms/optimize-allocation-liveness.mlir b/mlir/test/Dialect/Bufferization/Transforms/optimize-allocation-liveness.mlir
index 63d33e3a88bed..31fbbf80a9c6d 100644
--- a/mlir/test/Dialect/Bufferization/Transforms/optimize-allocation-liveness.mlir
+++ b/mlir/test/Dialect/Bufferization/Transforms/optimize-allocation-liveness.mlir
@@ -234,3 +234,47 @@ func.func private @test_alloc_with_multiple_results() -> () {
memref.dealloc %alloc2 : memref<64xf32>
return
}
+
+// -----
+
+// CHECK-LABEL: func.func private @test_alloc_no_non_dealloc_users() {
+// CHECK: %[[ALLOC:.*]] = memref.alloc() {alignment = 64 : i64} : memref<32xf32>
+// CHECK-NEXT: memref.dealloc %[[ALLOC]] : memref<32xf32>
+// CHECK-NEXT: return
+
+// The pass finds no last user when an alloc has only a dealloc as its user.
+// Verify the IR stays unchanged.
+func.func private @test_alloc_no_non_dealloc_users() {
+ %alloc = memref.alloc() {alignment = 64 : i64} : memref<32xf32>
+ memref.dealloc %alloc : memref<32xf32>
+ return
+}
+
+// -----
+
+// CHECK-LABEL: func.func private @test_dynamic_dimensions(
+// CHECK-SAME: %[[N:.*]]: index) {
+// CHECK: %[[C0:.*]] = arith.constant 0 : index
+// CHECK: %[[ALLOC:.*]] = memref.alloc(%[[N]]) {alignment = 64 : i64} : memref<?xf32>
+// CHECK: memref.load %[[ALLOC]][%[[C0]]]
+// CHECK: memref.dealloc %[[ALLOC]] : memref<?xf32>
+// CHECK: %[[ALLOC1:.*]] = memref.alloc() {alignment = 64 : i64} : memref<32xf32>
+// CHECK: arith.constant
+// CHECK: memref.store {{.*}}, %[[ALLOC1]][%[[C0]]]
+// CHECK: memref.dealloc %[[ALLOC1]] : memref<32xf32>
+// CHECK: return
+
+// The pass moves the dealloc of a dynamic alloc to right after its last user.
+// %alloc starts with its dealloc at the end of the block. The pass moves it
+// to right after the memref.load, which is the last use of %alloc.
+func.func private @test_dynamic_dimensions(%n: index) {
+ %c0 = arith.constant 0 : index
+ %alloc = memref.alloc(%n) {alignment = 64 : i64} : memref<?xf32>
+ %val = memref.load %alloc[%c0] : memref<?xf32>
+ %alloc_1 = memref.alloc() {alignment = 64 : i64} : memref<32xf32>
+ %cf0 = arith.constant 0.0 : f32
+ memref.store %cf0, %alloc_1[%c0] : memref<32xf32>
+ memref.dealloc %alloc : memref<?xf32>
+ memref.dealloc %alloc_1 : memref<32xf32>
+ return
+}
>From c060c5d256c3dea95b90e4bf755352bb74841fb8 Mon Sep 17 00:00:00 2001
From: Mohamed Deraz Nasr <mderaznasr at gmail.com>
Date: Mon, 30 Mar 2026 23:16:33 -0400
Subject: [PATCH 2/2] [mlir][bufferization] Add tests for
OptimizeAllocationLiveness edge cases
Add two test cases to optimize-allocation-liveness.mlir that cover
untested code paths in OptimizeAllocationLiveness.cpp:
1. An alloc with no users other than its dealloc. The pass hits the
lastUser == nullptr branch and leaves the IR unchanged.
2. An alloc with a dynamic dimension (memref<?xf32>). All existing
tests use static shapes. This verifies the pass moves the dealloc
to right after the last user when the alloc size is not known at
compile time.
---
.../optimize-allocation-liveness.mlir | 30 +++++++------------
1 file changed, 10 insertions(+), 20 deletions(-)
diff --git a/mlir/test/Dialect/Bufferization/Transforms/optimize-allocation-liveness.mlir b/mlir/test/Dialect/Bufferization/Transforms/optimize-allocation-liveness.mlir
index 31fbbf80a9c6d..27bca1214695a 100644
--- a/mlir/test/Dialect/Bufferization/Transforms/optimize-allocation-liveness.mlir
+++ b/mlir/test/Dialect/Bufferization/Transforms/optimize-allocation-liveness.mlir
@@ -237,13 +237,12 @@ func.func private @test_alloc_with_multiple_results() -> () {
// -----
-// CHECK-LABEL: func.func private @test_alloc_no_non_dealloc_users() {
-// CHECK: %[[ALLOC:.*]] = memref.alloc() {alignment = 64 : i64} : memref<32xf32>
-// CHECK-NEXT: memref.dealloc %[[ALLOC]] : memref<32xf32>
-// CHECK-NEXT: return
+// CHECK-LABEL: func.func private @test_alloc_no_non_dealloc_users
+// CHECK: %[[alloc:.*]] = memref.alloc
+// CHECK-NEXT: memref.dealloc %[[alloc]]
+// CHECK-NEXT: return
-// The pass finds no last user when an alloc has only a dealloc as its user.
-// Verify the IR stays unchanged.
+// No non-dealloc users. The pass should not move the dealloc.
func.func private @test_alloc_no_non_dealloc_users() {
%alloc = memref.alloc() {alignment = 64 : i64} : memref<32xf32>
memref.dealloc %alloc : memref<32xf32>
@@ -252,21 +251,12 @@ func.func private @test_alloc_no_non_dealloc_users() {
// -----
-// CHECK-LABEL: func.func private @test_dynamic_dimensions(
-// CHECK-SAME: %[[N:.*]]: index) {
-// CHECK: %[[C0:.*]] = arith.constant 0 : index
-// CHECK: %[[ALLOC:.*]] = memref.alloc(%[[N]]) {alignment = 64 : i64} : memref<?xf32>
-// CHECK: memref.load %[[ALLOC]][%[[C0]]]
-// CHECK: memref.dealloc %[[ALLOC]] : memref<?xf32>
-// CHECK: %[[ALLOC1:.*]] = memref.alloc() {alignment = 64 : i64} : memref<32xf32>
-// CHECK: arith.constant
-// CHECK: memref.store {{.*}}, %[[ALLOC1]][%[[C0]]]
-// CHECK: memref.dealloc %[[ALLOC1]] : memref<32xf32>
-// CHECK: return
+// CHECK-LABEL: func.func private @test_dynamic_dimensions
+// CHECK: %[[alloc:.*]] = memref.alloc
+// CHECK-NEXT: memref.load %[[alloc]]
+// CHECK-NEXT: memref.dealloc %[[alloc]]
-// The pass moves the dealloc of a dynamic alloc to right after its last user.
-// %alloc starts with its dealloc at the end of the block. The pass moves it
-// to right after the memref.load, which is the last use of %alloc.
+// The pass moves the dealloc of a dynamic alloc to right after its last use.
func.func private @test_dynamic_dimensions(%n: index) {
%c0 = arith.constant 0 : index
%alloc = memref.alloc(%n) {alignment = 64 : i64} : memref<?xf32>
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