[Bug Fixes] fix bug when backword kernel in the same file with forward (#67218)

Author: ming1753

cmake/phi.cmake

@@ -81,6 +81,11 @@ function(kernel_declare TARGET_LIST)
         "(PD_REGISTER_KERNEL|PD_REGISTER_KERNEL_FOR_ALL_DTYPE|PD_REGISTER_KERNEL_FOR_ALL_BACKEND_DTYPE|PD_REGISTER_KERNEL_FOR_ALL_BACKEND_DTYPE_EXCEPT_CUSTOM)\\([ \t\r\n]*[a-z0-9_]*,[[ \\\t\r\n\/]*[a-z0-9_]*]?[ \\\t\r\n]*[a-zA-Z_]*,[ \\\t\r\n]*[A-Z_]*"
         first_registry
         "${kernel_impl}")
+    if(DEFINED REDUCE_INFERENCE_LIB_SIZE)
+      if("${first_registry}" MATCHES ".*_grad,.*")
+        continue()
+      endif()
+    endif()
     set(kernel_declare_id "")
     while(NOT first_registry STREQUAL "")
       string(REPLACE "${first_registry}" "" kernel_impl "${kernel_impl}")
@@ -162,11 +167,6 @@ function(kernel_declare TARGET_LIST)
     endwhile()
     # append kernel declare into declarations.h
     if(NOT kernel_declare_id STREQUAL "")
-      if(DEFINED REDUCE_INFERENCE_LIB_SIZE)
-        if(${kernel_declare_id} MATCHES ".*_grad,.*")
-          continue()
-        endif()
-      endif()
       file(APPEND ${kernel_declare_file} "${kernel_declare_id}\n")
     endif()
   endforeach()