[TIR] Fix int32 vs int64 mismatch in For construct.

python/tvm/script/tir/scope_handler.py

@@ -467,18 +467,24 @@ def enter_scope(
 
         self.node = node
         self.context = context
-        # generate loop vars
-        self.loop_vars = [
-            tvm.te.var(name, dtype="int32", span=span) for name, span in zip(loop_var_names, spans)
-        ]
         # collect loop infos by calling self.func
         call_with_error_reporting(context.report_error, span, self.func, *arg_list)
-        if len(self.loop_vars) != len(self.loop_info):
+        if len(loop_var_names) != len(self.loop_info):
             self.context.report_error(
-                f"Inconsistent number of vars and loops, got {len(self.loop_vars)} "
+                f"Inconsistent number of vars and loops, got {len(loop_var_names)} "
                 + f"vs {len(self.loop_info)}",
                 self.node.span,
             )
+        # generate loop vars
+        self.loop_vars = []
+        for name, lv_span, li in zip(loop_var_names, spans, self.loop_info):
+            if not li.begin.dtype.startswith("int"):
+                raise NotImplementedError(f"Unsupported dtype in loop begin: {li.begin.dtype}")
+            if not li.extent.dtype.startswith("int"):
+                raise NotImplementedError(f"Unsupported dtype in loop extent: {li.extent.dtype}")
+            dtype = "int64" if "int64" in [li.begin.dtype, li.extent.dtype] else "int32"
+            self.loop_vars.append(tvm.te.var(name, dtype=dtype, span=lv_span))
+
         for loop_var, loop_info in zip(self.loop_vars, self.loop_info):
             context.update_symbol(loop_var.name, loop_var, node)
             context.loop_stack[loop_var] = Range.from_min_extent(loop_info.begin, loop_info.extent)

python/tvm/te/hybrid/parser.py

@@ -511,7 +511,13 @@ def visit_For(self, node):
 
         if iter_var is None:
             _internal_assert(kind is not None, "The loop iterating function parse error!")
-            offset = iter_var = tvm.te.var(_name)
+            if isinstance(ext, _expr.PrimExpr):
+                dtype = ext.dtype
+            elif isinstance(ext, int):
+                dtype = "int32"
+            else:
+                raise NotImplementedError(f"Unsupported type of ext: {type(ext)}")
+            offset = iter_var = tvm.te.var(_name, dtype=dtype)
             if not tvm.tir.analysis.expr_deep_equal(low, tvm.runtime.const(0, "int32")):
                 offset = iter_var + low
             self.add_symbol(_name, Symbol.LoopVar, offset)

python/tvm/tir/ir_builder.py

@@ -201,7 +201,7 @@ def scope_attr(self, node, attr_key, value):
             value = op.max(1, value)
         self.emit(lambda x: _stmt.AttrStmt(node, attr_key, value, x))
 
-    def for_range(self, begin, end, name="i", dtype="int32", kind="serial"):
+    def for_range(self, begin, end, name="i", dtype=None, kind="serial"):
         """Create a for iteration scope.
 
         Parameters
@@ -240,6 +240,26 @@ def for_range(self, begin, end, name="i", dtype="int32", kind="serial"):
             name = chr(ord(name) + self.nidx) if self.nidx < 3 else name + "_" + str(self.nidx - 3)
             self.nidx += 1
         self._seq_stack.append([])
+
+        # auto infer dtype when it's not specified
+        def get_dtype(expr):
+            if isinstance(expr, _expr.PrimExpr):
+                if not expr.dtype.startswith("int"):
+                    raise NotImplementedError(
+                        f"Infer loop_var dtype failed:"
+                        f" unsupported dtype in loop begin or end {expr.dtype}"
+                    )
+                return expr.dtype
+            if isinstance(expr, int):
+                return "int32"
+            raise NotImplementedError(
+                f"Infer loop_var dtype failed:"
+                f" unsupported dtype in loop begin or end {expr.dtype}"
+            )
+
+        if dtype is None:
+            dtype = "int64" if "int64" in [get_dtype(begin), get_dtype(end)] else "int32"
+
         loop_var = _expr.Var(name, dtype=dtype)
         extent = end if begin == 0 else (end - begin)
 

python/tvm/topi/cuda/scan.py

@@ -105,7 +105,7 @@ def exclusive_scan_ir(data, output, reduction=None, binop=tvm.tir.generic.add, i
         # Up Sweep of exclusive scan
         lim = ceil_log2(scan_axis_size)
 
-        with ib.for_range(0, lim, dtype="int64") as l2_width:
+        with ib.for_range(0, cast(lim, "int64"), dtype="int64") as l2_width:
             width = 2 << l2_width
 
             with ib.new_scope():
@@ -143,7 +143,7 @@ def exclusive_scan_ir(data, output, reduction=None, binop=tvm.tir.generic.add, i
                     reduction[bx] = output[(bx + 1) * scan_axis_size - 1]
                 output[(bx + 1) * scan_axis_size - 1] = cast(identity_value, out_dtype)
 
-        with ib.for_range(0, lim, dtype="int64") as l2_width:
+        with ib.for_range(0, cast(lim, "int64"), dtype="int64") as l2_width:
             width = 2 << (lim - l2_width - 1)
 
             with ib.new_scope():

python/tvm/topi/cuda/sort.py

@@ -323,7 +323,7 @@ def assign_j():
                 with ib.else_scope():
                     assign_j()
 
-    with ib.for_range(0, upper_lim - lower_lim, dtype="int64") as l2_width:
+    with ib.for_range(0, cast(upper_lim - lower_lim, "int64"), dtype="int64") as l2_width:
         width = 2 << (l2_width + lower_lim)
         # Define and launch the cuda kernel
         with ib.new_scope():

src/te/operation/op_utils.cc

@@ -128,7 +128,7 @@ std::vector<std::vector<Stmt> > MakeLoopNest(const Stage& stage,
         nest[i + 1].emplace_back(LetStmt(var, promote_to_bound_dtype(dom->min), no_op));
         value_map[iv] = promote_to_bound_dtype(dom->min);
       } else if (is_zero(dom->min)) {
-        nest[i + 1].emplace_back(For(var, 0, dom->extent, kind, no_op));
+        nest[i + 1].emplace_back(For(var, 0, promote_to_bound_dtype(dom->extent), kind, no_op));
         value_map[iv] = promote_to_bound_dtype(var);
       } else {
         Var idx(bind_iv->var->name_hint + ".idx", iv->var.dtype());

src/tir/ir/stmt.cc

@@ -147,6 +147,26 @@ For::For(Var loop_var, PrimExpr min, PrimExpr extent, ForKind kind, Stmt body,
   ICHECK(loop_var.dtype().is_scalar());
   ICHECK(body.defined());
 
+  // When extent or min is an IntImm but has narrower dtype than loop_var, we directly promote them
+  // without raising errors.
+  auto try_promote_imm_dtype = [&](const PrimExpr& e) {
+    ICHECK(e.dtype().bits() <= loop_var.dtype().bits())
+        << " Loop variable's dtype (" << loop_var.dtype()
+        << ") is narrower than that of `min` or `extent` (" << e.dtype() << ")";
+    const IntImmNode* a = e.as<IntImmNode>();
+    if (a && e.dtype().bits() < loop_var.dtype().bits()) {
+      return make_const(loop_var.dtype(), a->value);
+    } else {
+      return e;
+    }
+  };
+
+  min = try_promote_imm_dtype(min);
+  extent = try_promote_imm_dtype(extent);
+
+  ICHECK(loop_var.dtype() == min.dtype()) << loop_var.dtype() << " vs " << min.dtype();
+  ICHECK(loop_var.dtype() == extent.dtype()) << loop_var.dtype() << " vs " << extent.dtype();
+
   ObjectPtr<ForNode> node = make_object<ForNode>();
   node->loop_var = std::move(loop_var);
   node->min = std::move(min);

src/tir/schedule/primitive/cache_read_write.cc

@@ -108,7 +108,7 @@ Block MakeCacheStage(const BufferRegion& cache_region, CacheStageInfo* info,
   std::vector<PrimExpr> iter_values;
   // Create loop vars and block vars' binding_value
   for (const Range& axis_range : cache_region->region) {
-    Var loop_var("ax" + std::to_string(loop_vars.size()));
+    Var loop_var("ax" + std::to_string(loop_vars.size()), axis_range->extent.dtype());
     loop_vars.push_back(loop_var);
     iter_values.push_back(axis_range->min + loop_var);
   }

src/tir/transforms/vectorize_loop.cc

@@ -569,7 +569,8 @@ class Vectorizer : public StmtMutator, public ExprFunctor<PrimExpr(const PrimExp
     Var idx(var_->name_hint + ".s", var_->dtype);
     Map<Var, PrimExpr> values{{var_, idx}};
     stmt = Substitute(stmt, values);
-    return For(idx, 0, var_lanes_, ForKind::kSerial, stmt);
+    return For(idx, IntImm(var_->dtype, 0), IntImm(var_->dtype, var_lanes_), ForKind::kSerial,
+               stmt);
   }
   // ProducerStore
   Stmt VisitStmt_(const ProducerStoreNode* op) final {

tests/python/unittest/test_tir_buffer.py

@@ -99,7 +99,7 @@ def test_buffer_vload_nullptr():
     buf_load = tvm.tir.expr.BufferLoad(buffer=buf, indices=tvm.runtime.convert([0]))
     buf_load_stmt = tvm.tir.stmt.Evaluate(buf_load)
     for_loop = tvm.tir.stmt.For(
-        loop_var=var, kind=0, min_val=0, extent=buf_load, body=buf_load_stmt
+        loop_var=var, kind=0, min_val=0, extent=tvm.tir.Cast("int32", buf_load), body=buf_load_stmt
     )
     buf_func = tvm.tir.PrimFunc(params={}, body=for_loop)
     mod = tvm.IRModule({"main": buf_func})

tests/python/unittest/test_tir_ir_builder.py

@@ -517,7 +517,7 @@ def test_device_ir(A, B):
         temp[tx] = Aptr[tx]
         depth = tvm.tir.log2(cast(n, "float32"))
 
-        with ib.for_range(0, depth) as i:
+        with ib.for_range(0, cast(tvm.tir.ceil(depth), n.dtype)) as i:
             ib.emit(tvm.tir.Call(None, "tir.tvm_storage_sync", tvm.runtime.convert(["shared"])))
             d = n >> (i + 1)
             with ib.if_scope(tx < d):

tests/python/unittest/test_tir_transform_ir_utils.py

@@ -26,9 +26,9 @@ def test_convert_ssa():
     var_type = ir.PointerType(ir.PrimType(dtype))
     v = tir.Var("i1", var_type)
     buf = tir.decl_buffer([16], dtype=dtype, data=v)
-    for_stmt = tir.For(v, zero, zero, tir.ForKind.SERIAL, nop)
+    let = tir.LetStmt(v, v, nop)
     load = tir.Evaluate(tir.BufferLoad(buf, [zero]))
-    seq = tir.SeqStmt([for_stmt, for_stmt, load])
+    seq = tir.SeqStmt([let, let, load])
     func = tir.PrimFunc([], seq)
     mod = tvm.IRModule({"main": func})
     mod = tir.transform.InjectVirtualThread()(

tests/python/unittest/test_tir_transform_vectorize.py

@@ -85,6 +85,16 @@ def test_vectorize_with_if():
     assert isinstance(stmt.else_case, tvm.tir.For)
 
 
+def test_vectorize_with_if_cond_int64():
+    m = te.size_var("m", dtype="int64")
+    A = te.placeholder((m,), name="A", dtype="float32")
+    B = te.compute((m,), lambda i: te.if_then_else(i < 2, A[i], A[i] * 2), name="B")
+    s = te.create_schedule(B.op)
+    x, y = s[B].split(B.op.axis[0], factor=4)
+    s[B].vectorize(y)
+    f = tvm.build(s, [A, B], "llvm")
+
+
 def test_vectorize_let():
     v = tvm.tir.Var("v", "float32")
     ib = tvm.tir.ir_builder.create()