[Bug c/52355] New: [4.7 regression] address difference between array elements is not considered to be a compile time constant anymore

[siarhei.siamashka at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52355

             Bug #: 52355
           Summary: [4.7 regression] address difference between array
                    elements is not considered to be a compile time
                    constant anymore
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: siarhei.siamas...@gmail.com


Created attachment 26733
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26733
test.c

gcc version 4.7.0 20120223 (experimental) (GCC)

$ cat test.c
void f(char a[16][16][16])
{
    asm volatile ("" : : "i" (&a[1][0][0] - &a[0][0][0]));
}

int main(void)
{
    char a[16][16][16];
    f(a);
    return 0;
}

$ gcc -O2 test.c
test.c: In function ‘f’:
test.c:3:5: warning: asm operand 0 probably doesn’t match constraints [enabled
by default]
test.c:3:5: error: impossible constraint in ‘asm’