[TVM][BUGFIX] Fix missing reduction init predicates (apache#2495)

* [TVM][BUGFIX] Fix reductions in split axes

* A test case for the problem

* Fix the fix: skip loops that are related to reduction AND are unrelated to axis

src/op/compute_op.cc

@@ -457,11 +457,11 @@ ComputeLoopNest ComputeLoopNest::make(
       ret.init_vmap[iv] = ret.main_vmap.at(iv);
     }
     ret.num_common_loop = begin_loop;
-    // skip loops that does not relates to axis.
+    // skip loops that are related to reduction and are unrelated to axis.
     std::unordered_set<IterVar> skip_iter;
     for (auto kv : update_state) {
       int flag = kv.second;
-      if ((flag & 1) == 0) skip_iter.insert(kv.first);
+      if (flag == 2) skip_iter.insert(kv.first);
     }
     ret.init_nest = op::MakeLoopNest(
         stage, dom_map, begin_loop, true,

src/op/tensor_compute_op.cc

@@ -215,11 +215,11 @@ ComputeLoopNest MakeLoopNest(
       ret.init_vmap[iv] = ret.main_vmap.at(iv);
     }
     ret.num_common_loop = begin_loop;
-    // skip loops that does not relates to axis.
+    // skip loops that are related to reduction and are unrelated to axis.
     std::unordered_set<IterVar> skip_iter;
     for (auto kv : update_state) {
       int flag = kv.second;
-      if ((flag & 1) == 0) skip_iter.insert(kv.first);
+      if (flag == 2) skip_iter.insert(kv.first);
     }
     ret.init_nest = op::MakeLoopNest(
         stage, dom_map, begin_loop, true,

tests/python/unittest/test_schedule_schedule_ops.py

@@ -1,5 +1,5 @@
 import tvm
-
+import numpy as np
 
 def test_schedule0():
     m = tvm.var('m')
@@ -432,6 +432,32 @@ def f(n):
     s.cache_write(Y, 'local')
     f = tvm.build(s, [X, Y])
 
+def test_reduction_and_dummy_fuse_split():
+    n = 10
+    X = tvm.placeholder(shape=(n,), dtype='int32', name="X")
+    k = tvm.reduce_axis((0, n))
+    Y = tvm.compute((), lambda: tvm.sum(X[k], k), name="Y")
+    s = tvm.create_schedule([Y.op])
+    ax = s[Y.op].fuse(*Y.op.axis)
+    axo, axi = s[Y.op].split(ax, nparts=20)
+    f = tvm.build(s, [Y, X])
+
+    args = [tvm.nd.empty((), 'int32')] + [tvm.ndarray.array(np.ones((n,), dtype='int32'))]
+    f(*args)
+    assert args[0].asnumpy() == n
+
+    n = 10
+    X = tvm.placeholder(shape=(n,), dtype='int32', name="X")
+    k = tvm.reduce_axis((0, n))
+    Y = tvm.compute((n,), lambda i: tvm.sum(X[k], k), name="Y")
+    s = tvm.create_schedule([Y.op])
+    ax = s[Y.op].fuse(*(list(Y.op.axis) + list(Y.op.reduce_axis)))
+    f = tvm.build(s, [Y, X])
+
+    args = [tvm.ndarray.array(np.ones((n,), dtype='int32'))] + \
+        [tvm.ndarray.array(np.ones((n,), dtype='int32'))]
+    f(*args)
+    assert np.all(args[0].asnumpy() == n)
 
 if __name__ == "__main__":
     test_loop_dep_reduce()
@@ -456,3 +482,4 @@ def f(n):
     test_schedule_tensor_compute1()
     test_schedule_tensor_compute2()
     test_schedule_tensor_compute3()
+    test_reduction_and_dummy_fuse_split()