[Bug c/86505] New: __builtin_va_arg_pack_len() computes the number of arguments wrongly

[rpirrera at aitek dot it]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86505

            Bug ID: 86505
           Summary: __builtin_va_arg_pack_len() computes the number of
                    arguments wrongly
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rpirrera at aitek dot it
  Target Milestone: ---

I have found another issue with __builtin_va_arg_pack_len() that happens when
the functions that uses __builtin_va_arg_pack() calls another function that
uses __builtin_va_arg_pack_len(), the argument len is miscalculated as you can
see in the attached example.
This was working in GCC version 4.4.7.



#include <stdio.h>

/*************** TESTBUILTIN BEGIN ****************/
static inline __attribute__(( __always_inline__)) int 
funA(unsigned int param, ...) 
{ 
    return __builtin_va_arg_pack_len(); 
}

static inline __attribute__(( __always_inline__)) int
funB(unsigned int param, ...)
{ 
    return funA(param,  2, 4, __builtin_va_arg_pack()); 
}

int 
testBuiltin(void) 
{ 
    int rc = funB(0,1,2); 
    if (rc != 4) {
        return 1;
    }

    return 0;
}

int
main(void)
{
    int rc;

    rc = testBuiltin();
    if (rc == 1) {
        printf("Test Failed!\n");
        return rc; 
    }

    printf("Test Succeeded!\n");
    return rc;
}

Thank you!