Replace init_shared_mem definition with a C++ one

Author: kurapov-peter

omniscidb/QueryEngine/Compiler/genx.cpp

@@ -18,6 +18,11 @@ double atomic_min_double(GENERIC_ADDR_SPACE double* addr, const double val);
 double atomic_min_float(GENERIC_ADDR_SPACE float* addr, const float val);
 double atomic_max_double(GENERIC_ADDR_SPACE double* addr, const double val);
 double atomic_max_float(GENERIC_ADDR_SPACE float* addr, const float val);
+GENERIC_ADDR_SPACE int64_t* declare_dynamic_shared_memory();
+
+void sync_threadblock();
+int64_t get_thread_index();
+int64_t get_block_dim();
 
 void agg_max_shared(GENERIC_ADDR_SPACE int64_t* agg, const int64_t val);
 int64_t agg_count_shared(GENERIC_ADDR_SPACE int64_t* agg, const int64_t val);
@@ -87,4 +92,17 @@ void agg_max_double_skip_val_shared(GENERIC_ADDR_SPACE int64_t* agg,
     agg_max_double_shared(agg, val);
   }
 }
+
+const GENERIC_ADDR_SPACE int64_t* init_shared_mem(
+    const GENERIC_ADDR_SPACE int64_t* global_groups_buffer,
+    const int32_t groups_buffer_size) {
+  auto shared_groups_buffer = declare_dynamic_shared_memory();
+  const int32_t buffer_units = groups_buffer_size >> 3;
+
+  for (int32_t pos = get_thread_index(); pos < buffer_units; pos += get_block_dim()) {
+    shared_groups_buffer[pos] = global_groups_buffer[pos];
+  }
+  sync_threadblock();
+  return shared_groups_buffer;
+}
 }

omniscidb/QueryEngine/Compiler/genx.ll

@@ -25,6 +25,11 @@ define void @sync_threadblock() {
     ret void
 }
 
+define i64 @get_block_dim() {
+    %gsize = call i64 @__spirv_BuiltInWorkgroupSize(i32 0)
+    ret i64 %gsize
+}
+
 define i32 @pos_start_impl(i32 addrspace(4)* %0)  readnone nounwind alwaysinline {
     %gid = call i64 @__spirv_BuiltInWorkgroupId(i32 0)
     %gsize = call i64 @__spirv_BuiltInWorkgroupSize(i32 0)
@@ -322,30 +327,6 @@ define void @agg_count_distinct_bitmap_gpu(i64 addrspace(4)* %agg, i64 noundef %
     ret void
 }
 
-define i64 addrspace(4)* @init_shared_mem(i64 addrspace(4)* %agg_init_val, i32 noundef %groups_buffer_size) {
-.entry:
-    %buf.units = ashr i32 %groups_buffer_size, 3
-    %buf.units.i64 = sext i32 %buf.units to i64
-    %pos = call i64 @get_thread_index()
-    %wgnum = call i64 @__spirv_BuiltInNumWorkgroups(i32 0)
-    %loop.cond = icmp slt i64 %pos, %buf.units.i64
-    br i1 %loop.cond, label %.for_body, label %.exit
-.for_body:
-    %pos.idx = phi i64 [ %pos, %.entry ], [ %pos.idx.new, %.for_body ]
-    %agg_init_val.idx = getelementptr inbounds i64, i64 addrspace(4)* %agg_init_val, i64 %pos.idx
-    %slm.idx = getelementptr inbounds [4096 x i64], [4096 x i64] addrspace(3)* @slm.buf.i64, i64 0, i64 %pos.idx
-    %val = load i64, i64 addrspace(4)* %agg_init_val.idx
-    store i64 %val, i64 addrspace(3)* %slm.idx
-    %pos.idx.new = add nsw i64 %pos.idx, %wgnum
-    %cond = icmp slt i64 %pos.idx.new, %buf.units.i64
-    br i1 %cond, label %.for_body, label %.exit
-.exit:
-    call void @sync_threadblock()
-    %res.ptr = bitcast [4096 x i64] addrspace(3)* @slm.buf.i64 to i64 addrspace(3)*
-    %res.ptr.casted = addrspacecast i64 addrspace(3)* %res.ptr to i64 addrspace(4)*
-    ret i64 addrspace(4)* %res.ptr.casted
-}
-
 define void @write_back_non_grouped_agg(i64 addrspace(4)* %input_buffer, i64 addrspace(4)* %output_buffer, i32 noundef %agg_idx) {
     %tid = call i64 @get_thread_index()
     %agg_idx.i64 = sext i32 %agg_idx to i64