fix(imperative): fix matmul deduce dtype

GitOrigin-RevId: 24f4e1f9fc1fb58b3443d04c13e95e7493d119d1

imperative/python/test/unit/quantization/test_op.py

@@ -340,3 +340,19 @@ def test_conv_transpose2d():
     test_func(2, 4, 3, 1, 8, 1, 1, 1, 1, 0, 0, 1, 1, 1, False)
     test_func(4, 4, 16, 16, 8, 3, 3, 1, 1, 1, 1, 1, 1, 1, False)
     test_func(32, 64, 36, 28, 16, 3, 2, 1, 3, 1, 0, 1, 1, 1, False)
+
+
+def test_matmul():
+    inp_scale = np.float32(np.random.rand())
+    weight_scale = np.float32(np.random.rand())
+    inp_dtype = dtype.qint8(inp_scale)
+    weight_dtype = dtype.qint8(weight_scale)
+
+    inp_data = np.random.random((3, 12))
+    weight_data = np.random.random((5, 12))
+    inp_int8 = mge.tensor(dtype.convert_to_qint8(inp_data, inp_dtype))
+    weight_int8 = mge.tensor(dtype.convert_to_qint8(weight_data, weight_dtype))
+
+    res = F.matmul(inp_int8, weight_int8, transpose_b=True)
+    res_scale = dtype.get_scale(res.dtype)
+    np.testing.assert_allclose(inp_scale * weight_scale, res_scale)

imperative/src/impl/ops/matmul.cpp

@@ -104,7 +104,7 @@ std::tuple<SmallVector<LogicalTensorDesc>, bool> infer_output_attrs_fallible(
     }
 
     DnnOprHelper<megdnn::MatrixMul> dnn_opr(matmul.param());
-    dnn_opr.opr().deduce_dtype(layout1.dtype, layout1.dtype, dst_dtype);
+    dnn_opr.opr().deduce_dtype(layout1.dtype, layout2.dtype, dst_dtype);
 
     if (dim1 == 0 || dim2 == 0) {
         return {{{TensorLayout(dst_dtype), inputs[0].comp_node}}, false};
@@ -157,7 +157,7 @@ SmallVector<TensorPtr> apply_on_physical_tensor(
     }
 
     DType dst_dtype;
-    dnn_opr.op()->deduce_dtype(layout1.dtype, layout1.dtype, dst_dtype);
+    dnn_opr.op()->deduce_dtype(layout1.dtype, layout2.dtype, dst_dtype);
 
     // only matters when layout1 has dim 2
     if (matmul.transposeA)
@@ -335,7 +335,7 @@ std::tuple<SmallVector<LogicalTensorDesc>, bool> infer_output_attrs_fallible(
     DType dst_dtype;
 
     DnnOprHelper<megdnn::MatrixMul> dnn_opr(matmul.param());
-    dnn_opr.opr().deduce_dtype(layout1.dtype, layout1.dtype, dst_dtype);
+    dnn_opr.opr().deduce_dtype(layout1.dtype, layout2.dtype, dst_dtype);
 
     if (dim1 == 0 || dim2 == 0) {
         return {{{TensorLayout(dst_dtype), inputs[0].comp_node}}, false};
@@ -378,7 +378,7 @@ SmallVector<TensorPtr> apply_on_physical_tensor(
 
     DnnOprCaller<megdnn::BatchedMatrixMul> dnn_opr(cn, matmul.param(), matmul.policy());
     DType dst_dtype;
-    dnn_opr.op()->deduce_dtype(layout1.dtype, layout1.dtype, dst_dtype);
+    dnn_opr.op()->deduce_dtype(layout1.dtype, layout2.dtype, dst_dtype);
 
     TensorShape tshp, batch_shp;
     size_t j = 0;