[CODEGEN] Fixes masked load exception (#342)

include/triton/codegen/analysis/axes.h

@@ -27,7 +27,8 @@ private:
   void update_graph_trans(ir::instruction *i);
   void update_graph_broadcast(ir::instruction *i);
   void update_graph_dot(ir::instruction *i);
-  void update_graph_elementwise(ir::instruction *i, bool connect_ret=true);
+  void update_graph_elementwise(ir::instruction *i,
+                                bool is_masked_load_async=false);
   void update_graph_no_edge(ir::instruction *i);
   void update_graph(ir::instruction *i);
 

lib/codegen/analysis/axes.cc

@@ -79,21 +79,30 @@ void axes::update_graph_dot(ir::instruction *i) {
     graph_.add_edge({dot, d}, {D, d});
 }
 
-void axes::update_graph_elementwise(ir::instruction *i, bool connect_ret) {
+void axes::update_graph_elementwise(ir::instruction *i, 
+                                    bool is_masked_load_async) {
   if(i->get_num_operands() == 0)
     return;
   ir::value *op = i->get_operand(0);
   if(!op->get_type()->is_block_ty())
     return;
   auto rank = op->get_type()->get_tile_rank();
-  for(unsigned d = 0; d < rank; d++)
+  for(unsigned d = 0; d < rank; d++) {
+    // If we are dealing with a masked async load we need to attach the
+    // dimensions so we match the behaviour of the copy_to_shared instruction
+    // which async masked load replaces.
+    if (is_masked_load_async) {
+      graph_.add_edge({i, d}, {i, d});
+    }
+
     for(ir::value* opx: i->ops())
     for(ir::value* opy: i->ops()) {
-    if(connect_ret && !i->get_type()->is_void_ty())
+      if(!is_masked_load_async && !i->get_type()->is_void_ty())
         graph_.add_edge({i, d}, {opx, d});
       graph_.add_edge({opx, d}, {opy, d});
     }
   }
+}
 
 void axes::update_graph_no_edge(ir::instruction *i) {
   if(!i->get_type()->is_block_ty())
@@ -112,7 +121,7 @@ void axes::update_graph(ir::instruction *i) {
     case ir::INST_BROADCAST:         return update_graph_broadcast(i);
     case ir::INST_DOT:               return update_graph_dot(i);
     case ir::INST_COPY_TO_SHARED:    return update_graph_no_edge(i);
-    case ir::INST_MASKED_LOAD_ASYNC: return update_graph_elementwise(i, false);
+    case ir::INST_MASKED_LOAD_ASYNC: return update_graph_elementwise(i, true);
     case ir::INST_COPY_FROM_SHARED:  return update_graph_no_edge(i);
     case ir::INST_CVT_LAYOUT:        return update_graph_no_edge(i);
     default:                         return update_graph_elementwise(i);

python/test/unit/language/test_core.py

@@ -549,6 +549,55 @@ def test_arange(start, device='cuda'):
 # ---------------
 # test load
 # ---------------
+# 'bfloat16': torch.bfloat16,
+# Testing masked loads with an intermate copy to shared memory run.
+@pytest.mark.parametrize("dtype", [torch.float16, torch.float32])
+def test_masked_load_shared_memory(dtype, device='cuda'):
+    M = 32
+    N = 32
+    K = 8
+
+    in1 = torch.rand((M, K), dtype=dtype, device=device)
+    in2 = torch.rand((K, N), dtype=dtype, device=device)
+    out = torch.zeros((M, N), dtype=dtype, device=device)
+
+    @triton.jit
+    def _kernel(in1_ptr, in2_ptr, output_ptr,
+                in_stride, in2_stride, out_stride,
+                in_numel, in2_numel, out_numel, **meta):
+        M = meta['M']
+        N = meta['N']
+        K = meta['K']
+
+        M_offsets = tl.arange(0, M)
+        N_offsets = tl.arange(0, N)
+        K_offsets = tl.arange(0, K)
+
+        in_offsets =  M_offsets[:, None] * in_stride + K_offsets[None,:]
+        in2_offsets =  K_offsets[:, None] * in2_stride + N_offsets[None,:]
+
+        # Load inputs.
+        x = tl.load(in1_ptr + in_offsets, mask=in_offsets < in_numel)
+        w = tl.load(in2_ptr + in2_offsets, mask=in2_offsets < in2_numel)
+
+        # Without a dot product the memory doesn't get promoted to shared.
+        o = tl.dot(x, w)
+
+        # Store output
+        output_offsets =  M_offsets[:, None] * out_stride + N_offsets[None,:]
+        tl.store(output_ptr + output_offsets, o, mask=output_offsets < in2_numel)
+
+    pgm = _kernel[(1,)](in1, in2, out,
+                  in1.stride()[0],
+                  in2.stride()[0],
+                  out.stride()[0],
+                  in1.numel(),
+                  in2.numel(),
+                  out.numel(),
+                  M=M, N=N, K=K)
+
+    reference_out =torch.matmul(in1, in2)
+    triton.testing.allclose(out, reference_out)
 
 # ---------------
 # test store