type casting

[N V Krishna]

Hi,
I have the following C code :
main(){				 
        int *p;

        p=p+(unsigned int)p;

}
 
When I am inspecting the AST using debug_tree, the following is shown :
I am just printing the tree for the plus_expr :

-------
arg 1 <plus_expr 0x401c0500 type <pointer_type 0x401bf9c0>
    arg 0 <var_decl 0x401c8dd0 p>
    arg 1 <convert_expr 0x401bde74 type <pointer_type 0x401bf9c0>

        arg 0 <mult_expr 0x401c04a0 type <integer_type 0x401bc340 unsigned int>

            arg 0 <nop_expr 0x401bde24 type <integer_type 0x401bc340 unsigned int>

                arg 0 <convert_expr 0x401bde10 type <integer_type 0x401bc2d8 int>
                    arg 0 <var_decl 0x401c8dd0 p>>>
            arg 1 <integer_cst 0x401c0480 constant 4>>>>>


------

My question is regarding the first convert_expr. If I translate it then it
means :
(int *)(p + (int *)(((unsigned int)(int)p)*4))

// NOTE : On my machine sizeof(int) = 4.

If we omit some of the obvious casts :
p + (int *)((unsigned int )p * 4)

But gcc does not allow addition of two pointers. Is it an incorrect
representation of C code or I am missing something?

One more question is that, it seems incorrect to translate
(unsigned int)p
to
(unsigned int)(int)p ?  

I feel so; unless, again I am missing something.

I am trying to write a unparser for gcc's AST. Given a
function/statement/expression node, the unparser will print the C code for
that. This could be helpful for people working on different
transformations on the trees.

Warm regards
Krishna

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