Re: [Tinycc-devel] Integer constant expression bug

[Elijah Stone]

Actually, the problem is with the CEXPR_EH macro; it always returns 1.

If I replace the definition with '#define CEXPR_EH __builtin_constant_p', 
all of your tests pass.

I guess the problem is that the behaviour of this clause (from 6.5.15p6) 
is not correctly implemented:

> if one operand is a null pointer constant, the result has the type of 
> the other operand

 -E

On Thu, 20 May 2021, Petr Skocik wrote:

> Hi.
>
> Not sure if this is news but tinycc treats certain values which are
> definitely not integer constant expressions as if they were.
>
> Examples:
>
> #define CEXPR_EH(X) _Generic((1? (void *) ((!!(X))*0ll) : (int *) 0),
> int*: 1, void*: 0)
> //ok
> void should_be_ok1(void) { enum{x=0};  _Static_assert(CEXPR_EH(x),"");  }
>
> //each of these fails on tinycc
> void should_be_ok2(void) {  extern int x; 
> _Static_assert(!CEXPR_EH(x),"");  }
> void should_be_ok3(void) {  int x=0;  _Static_assert(!CEXPR_EH(x),"");  }
> void should_be_ok4(int x) {  _Static_assert(!CEXPR_EH(x),"");  }
> void should_be_ok5(void) {  double x=0;  _Static_assert(!CEXPR_EH(x),"");  }
> void should_be_ok6(void) {  extern double y; 
> _Static_assert(!CEXPR_EH(y),"");  }
> void should_be_ok7(void) {  char *x=0 ;  _Static_assert(!CEXPR_EH(x),"");  }
> void should_be_ok8(char *x) { _Static_assert(!CEXPR_EH(x),"");  }
>
> Regards,
>
> Petr S.
>
>
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