Re: [PATCH] fix a couple of bugs in const string folding (PR 86532)

[Bernd Edlinger]

I think I have found a valid test case where the latest patch
does generate invalid code:

$ cat part.c
static const char a[3][8] = { "1234", "12345", "123456" };

int main ()
{
   volatile int i = 1;
   int n = __builtin_strlen (*(&a[1]+i));

   if (n != 6)
     __builtin_abort ();
}
$ gcc part.c -fdump-tree-original
$ ./a.out
Aborted (core dumped)
$ cat part.c.004t.original

;; Function main (null)
;; enabled by -tree-original


{
   volatile int i = 1;
   int n = (ssizetype) (SAVE_EXPR <(long unsigned int) i * 8>) <= 5 ? (int) (5 
- (unsigned int) (SAVE_EXPR <(long unsigned int) i * 8>)) : 0;

     volatile int i = 1;
     int n = (ssizetype) (SAVE_EXPR <(long unsigned int) i * 8>) <= 5 ? (int) 
(5 - (unsigned int) (SAVE_EXPR <(long unsigned int) i * 8>)) : 0;
   if (n != 6)
     {
       __builtin_abort ();
     }
}
return 0;


string_constant is called with arg = (const char *) (&a[1] + (sizetype) ((long 
unsigned int) i * 8))



Bernd.