[Feature] Enhance fill operation to support various buffer types (#1189)

* [Feature] Enhance fill operation to support various buffer types

- Added support for `BufferLoad` in the `fill` function to handle different buffer types.
- Updated `Fill` class to process region descriptors and buffer regions, improving flexibility in buffer handling.
- Introduced checks for static bounds in region definitions to ensure safety during operations.
- Refactored loop induction variable handling in `FillNode` to accommodate sliced regions.

* lint fix

src/op/fill.cc

@@ -17,6 +17,7 @@
 #include "../transform/loop_partition.h"
 #include "../transform/loop_vectorize.h"
 #include "builtin.h"
+#include "region.h"
 
 namespace tvm {
 namespace tl {
@@ -62,7 +63,30 @@ using namespace tir;
 Fill::Fill(Array<PrimExpr> args, BufferMap vmap) {
   ObjectPtr<FillNode> node = tvm::ffi::make_object<FillNode>();
 
-  if (args[0]->IsInstance<BufferLoadNode>()) {
+  // Case 1: Region descriptor call (tl.region)
+  if (const auto *call = args[0].as<CallNode>()) {
+    if (call->op.same_as(RegionOp::Get())) {
+      auto region = RegionOp(call->args, vmap);
+      node->dst = region->GetBuffer();
+      node->region = region->GetRanges();
+    } else if (call->op.same_as(builtin::tvm_access_ptr())) {
+      node->dst = vmap[GetVarFromAccessPtr(args[0])];
+      for (int i = 0; i < node->dst->shape.size(); i++) {
+        node->region.push_back(Range(0, node->dst->shape[i]));
+      }
+    } else {
+      ICHECK(false) << "Unsupported call op in tl.fill: "
+                    << Downcast<Op>(call->op)->name;
+    }
+
+    // Case 2: Explicit BufferRegion (legacy path)
+  } else if (args[0]->IsInstance<BufferRegionNode>()) {
+    auto region = Downcast<BufferRegion>(args[0]);
+    node->dst = region->buffer;
+    node->region = region->region;
+
+    // Case 3: Vector/scalar region expressed via BufferLoad indices
+  } else if (args[0]->IsInstance<BufferLoadNode>()) {
     auto buffer_load = Downcast<BufferLoad>(args[0]);
     for (const auto &index : buffer_load->indices) {
       if (const auto *ramp = index.as<RampNode>()) {
@@ -77,6 +101,7 @@ Fill::Fill(Array<PrimExpr> args, BufferMap vmap) {
       }
     }
     node->dst = buffer_load->buffer;
+    // Case 4: Access pointer, fill the full buffer
   } else {
     node->dst = vmap[GetVarFromAccessPtr(args[0])];
     for (int i = 0; i < node->dst->shape.size(); i++) {
@@ -95,14 +120,19 @@ Fill::Fill(Array<PrimExpr> args, BufferMap vmap) {
       << " != " << node->dst->shape.size();
   for (int i = 0; i < node->region.size(); i++) {
     // bound check if region is static
-    if (node->region[i]->min.as<IntImm>()) {
-      int64_t min = Downcast<IntImm>(node->region[i]->min)->value;
+    if (const auto *min_imm = node->region[i]->min.as<IntImmNode>()) {
+      int64_t min = min_imm->value;
       ICHECK_GE(min, 0) << "region[" << i << "] = " << min << " < 0";
     }
-    if (node->region[i]->extent.as<IntImm>()) {
-      int64_t extent = Downcast<IntImm>(node->region[i]->extent)->value;
-      ICHECK_LE(extent, Downcast<IntImm>(node->dst->shape[i])->value)
-          << "region[" << i << "] = " << extent << " > " << node->dst->shape[i];
+    if (const auto *extent_imm = node->region[i]->extent.as<IntImmNode>()) {
+      // Only perform the upper-bound check when the destination shape
+      // extent is also statically known. If the shape is symbolic (e.g., Var),
+      // skip this static check to avoid invalid downcasts.
+      if (const auto *shape_imm = node->dst->shape[i].as<IntImmNode>()) {
+        ICHECK_LE(extent_imm->value, shape_imm->value)
+            << "region[" << i << "] = " << extent_imm->value << " > "
+            << node->dst->shape[i];
+      }
     }
   }
   data_ = std::move(node);
@@ -140,7 +170,8 @@ For FillNode::MakeSIMTLoop(arith::Analyzer *analyzer) const {
   for (int i = 0; i < ndim; i++) {
     Var var = Var(std::string{char('i' + i)}, region[i]->extent->dtype);
     loop_vars.push_back({region[i], var, IterVarType::kDataPar});
-    dst_indices.push_back(var);
+    // Offset the loop induction variable by region min to honor sliced regions
+    dst_indices.push_back(region[i]->min + var);
   }
   Stmt body = BufferStore(dst, value, dst_indices);
   for (int i = ndim - 1; i >= 0; i--) {
@@ -202,6 +233,7 @@ Stmt FillNode::Lower(const LowerArgs &T, arith::Analyzer *analyzer) const {
     return vectorized_thread_loop;
   } else {
     LOG(FATAL) << "Unsupported scope " << dst.scope();
+    return Stmt();
   }
 }
 
@@ -229,4 +261,4 @@ TIR_REGISTER_TL_OP(Fill, fill)
 TVM_FFI_STATIC_INIT_BLOCK() { FillNode::RegisterReflection(); }
 
 } // namespace tl
-} // namespace tvm
\ No newline at end of file
+} // namespace tvm

testing/python/issue/test_tilelang_issue_1008.py

+import torch
+import tilelang
+import tilelang.testing
+from tilelang import language as T
+
+
+@tilelang.jit(
+    pass_configs={
+        tilelang.PassConfigKey.TL_DISABLE_WARP_SPECIALIZED: True,
+        tilelang.PassConfigKey.TL_DISABLE_TMA_LOWER: True,
+    },)
+def _fill_with_static_region_kernel():
+    num_tokens = T.symbolic('num_tokens')
+
+    @T.prim_func
+    def buggy_kernel(x: T.Tensor[(num_tokens,), 'int64']):  # noqa: F821
+        with T.Kernel(num_tokens, threads=128) as _:
+            T.fill(x[0:128], 0)
+
+    return buggy_kernel
+
+
+@tilelang.jit(
+    pass_configs={
+        tilelang.PassConfigKey.TL_DISABLE_WARP_SPECIALIZED: True,
+        tilelang.PassConfigKey.TL_DISABLE_TMA_LOWER: True,
+    },)
+def _fill_with_dynamic_region_kernel():
+    num_tokens = T.symbolic('num_tokens')
+
+    @T.prim_func
+    def buggy_kernel(x: T.Tensor[(num_tokens,), 'int64']):  # noqa: F821
+        with T.Kernel(num_tokens, threads=128) as _:
+            a, b = T.alloc_var('int'), T.alloc_var('int')
+            T.fill(x[a:b], 0)
+
+    return buggy_kernel
+
+
+def test_fill_with_static_region_kernel():
+    kernel = _fill_with_static_region_kernel()
+    x = torch.zeros((256,), dtype=torch.int64, device='cuda')
+    kernel(x)
+
+
+def test_fill_with_dynamic_region_kernel():
+    kernel = _fill_with_dynamic_region_kernel()
+    x = torch.zeros((256,), dtype=torch.int64, device='cuda')
+    kernel(x)
+
+
+if __name__ == '__main__':
+    tilelang.testing.main()

tilelang/language/fill.py

@@ -4,9 +4,14 @@ from __future__ import annotations
 from tvm import tir
 from tilelang.language import has_let_value, get_let_value
 from tilelang.utils.language import get_buffer_region_from_load
+from tilelang.language.utils import (
+    buffer_to_tile_region,
+    buffer_region_to_tile_region,
+    buffer_load_to_tile_region,
+)
 
 
-def fill(buffer: tir.Buffer | tir.BufferRegion, value: tir.PrimExpr):
+def fill(buffer: tir.Buffer | tir.BufferRegion | tir.BufferLoad, value: tir.PrimExpr):
     """Fill a buffer or buffer region with a specified value.
 
     Args:
@@ -16,9 +21,30 @@ def fill(buffer: tir.Buffer | tir.BufferRegion, value: tir.PrimExpr):
     Returns:
         A TVM intrinsic call that performs the fill operation
     """
+    # Normalize Var with let value to its underlying object
+    if isinstance(buffer, tir.Var) and has_let_value(buffer):
+        buffer = get_let_value(buffer)
+
+    # Convert to a tl.region descriptor (PrimExpr) with write access
+    region_call = None
     if isinstance(buffer, tir.Buffer):
-        buffer = buffer.access_ptr("w")  # Get write pointer if input is a Buffer
-    return tir.call_intrin("handle", tir.op.Op.get("tl.fill"), buffer, value)
+        region_call = buffer_to_tile_region(buffer, "w")
+    elif isinstance(buffer, tir.BufferRegion):
+        extents = [r.extent for r in buffer.region]
+        region_call = buffer_region_to_tile_region(buffer, "w", extents)
+    elif isinstance(buffer, tir.BufferLoad):
+        region = get_buffer_region_from_load(buffer)
+        if region is not None:
+            extents = [r.extent for r in region.region]
+            region_call = buffer_region_to_tile_region(region, "w", extents)
+        else:
+            # Fallback: treat element access as 1-extent per dim
+            region_call = buffer_load_to_tile_region(buffer, "w", [1] * len(buffer.indices))
+    else:
+        # As-is fallback (rare): pass through for downstream handling
+        region_call = buffer
+
+    return tir.call_intrin("handle", tir.op.Op.get("tl.fill"), region_call, value)
 
 
 def clear(buffer: tir.Buffer | tir.Var):