gcc/testsuite/gcc.dg/20011119-1.c

   1 /* Test for reload failing to eliminate from argp to sp.  */
   2 /* { dg-do run { target i?86-*-* } } */
   3 /* { dg-options "-O2 -fomit-frame-pointer" } */
   4
   5 static int ustrsize (const char *s);
   6 static int (*ucwidth) (int c);
   7 static int (*ugetxc) (const char **s);
   8 static int (*usetc) (char *s, int c);
   9
  10 char *ustrzcat(char *dest, int size, const char *src)
  11 {
  12    int pos = ustrsize(dest);
  13    int c;
  14
  15    size -= pos + ucwidth(0);
  16
  17    while ((c = ugetxc(&src)) != 0) {
  18       size -= ucwidth(c);
  19       if (size < 0)
  20          break;
  21
  22       pos += usetc(dest+pos, c);
  23    }
  24
  25    usetc(dest+pos, 0);
  26
  27    return dest;
  28 }
  29
  30 static int __attribute__((noinline))
  31 ustrsize (const char *s)
  32 {
  33   return 0;
  34 }
  35
  36 static int
  37 ucwidth_ (int c)
  38 {
  39   return 1;
  40 }
  41
  42 static int
  43 ugetxc_ (const char **s)
  44 {
  45   return '\0';
  46 }
  47
  48 static int
  49 usetc_ (char *s, int c)
  50 {
  51   return 1;
  52 }
  53
  54 int
  55 main()
  56 {
  57   ucwidth = ucwidth_;
  58   ugetxc = ugetxc_;
  59   usetc = usetc_;
  60
  61   /* ??? It is impossible to explicitly modify the hard frame pointer.
  62      This will run afoul of code in flow.c that declines to mark regs
  63      in eliminate_regs in regs_ever_used.  Apparently, we have to wait
  64      for reload to decide that it won't need a frame pointer before a
  65      variable can be allocated to %ebp.
  66
  67      So save, restore, and clobber %ebp by hand.  */
  68
  69   asm ("pushl %%ebp\n\t"
  70        "movl $-1, %%ebp\n\t"
  71        "pushl $0\n\t"
  72        "pushl $0\n\t"
  73        "pushl $0\n\t"
  74        "call %P0\n\t"
  75        "addl $12, %%esp\n\t"
  76        "popl %%ebp"
  77        : : "i"(ustrzcat));
  78
  79   return 0;
  80 }