[TIR] Add test to cover specific case of reducer match buffer checking

tests/python/unittest/test_tir_transform_lower_cross_thread_reduction.py

@@ -548,6 +548,56 @@ def single_reduction_loop_with_tensorize(
                 )
 
 
+@T.prim_func
+def nested_reduction_loop_with_inner_match_buffers(
+    in0: T.Buffer[(4, 16), "int8"],
+    in1: T.Buffer[(4, 16), "int8"],
+    out: T.Buffer[(4, 4), "int32"],
+) -> None:
+    # body
+    # with T.block("root")
+    for y in T.serial(4):
+        with T.block("C"):
+            yi = T.axis.spatial(4, y)
+            T.reads(in0[yi, 0:16], in1[yi, 0:16])
+            T.writes(out[yi, 0:4])
+            for x in T.serial(4):
+                with T.block("C"):
+                    xr = T.axis.reduce(4, x)
+                    with T.init():
+                        for i in T.serial(4):
+                            with T.block("C_init"):
+                                ii = T.axis.spatial(4, i)
+                                T.reads()
+                                T.writes(out[yi, ii])
+                                out[yi, ii] = 0
+                    with T.block("C"):
+                        T.reads(
+                            out[yi, xr],
+                            in0[yi, yi * 4 + xr : yi * 4 + xr + 4],
+                            in1[yi, yi * 4 + xr : yi * 4 + xr + 4],
+                        )
+                        T.writes(out[yi, xr])
+                        A = T.match_buffer(
+                            in0[yi, yi * 4 + xr : yi * 4 + xr + 4],
+                            [4],
+                            dtype="int8",
+                            offset_factor=1,
+                        )
+                        B = T.match_buffer(
+                            in1[yi, yi * 4 + xr : yi * 4 + xr + 4],
+                            [4],
+                            dtype="int8",
+                            offset_factor=1,
+                        )
+                        C = T.match_buffer(out[yi, xr], [1], dtype="int32", offset_factor=1)
+                        A_i8x4: T.int8x4 = A[0:4]
+                        A_i32: T.int32 = T.reinterpret(A_i8x4, dtype="int32")
+                        B_i8x4: T.int8x4 = B[0:4]
+                        B_i32: T.int32 = T.reinterpret(B_i8x4, dtype="int32")
+                        C[0] = A_i32 + B_i32 + C[0]
+
+
 @T.prim_func
 def reducer_max(a: T.handle, b: T.handle) -> None:
     A = T.match_buffer(a, [128, 128], dtype="float32")
@@ -1247,6 +1297,13 @@ def test_single_reduction_loop_with_tensorize():
     )
 
 
+def test_nested_reduction_loop_with_inner_match_buffers():
+    _check(
+        nested_reduction_loop_with_inner_match_buffers,
+        nested_reduction_loop_with_inner_match_buffers,
+    )
+
+
 def test_reducer_max():
     _check(reducer_max, lowered_reducer_max)