[codegen] [selection] re-arranged file structure

lib/codegen/selection/selection.cc

@@ -0,0 +1,20 @@
+#include <numeric>
+#include "triton/codegen/selection/selection.h"
+#include "triton/codegen/selection/generator.h"
+#include "triton/ir/module.h"
+
+namespace triton{
+namespace codegen{
+
+using namespace llvm;
+
+void selection::run(ir::module &src, Module &dst) {
+  generator gen(&dst, a_axes_, tgt_, layouts_, alignment_, alloc_, num_warps_ );
+  for(ir::alloc_const *x: src.allocs())
+    gen.visit_alloc_const(x);
+  for(ir::function *fn: src.get_function_list())
+    gen.visit_function(fn);
+}
+
+}
+}