gcc/testsuite/gcc.target/i386/20011119-1.c

   1 /* Test for reload failing to eliminate from argp to sp.  */
   2 /* { dg-do run } */
   3 /* { dg-require-effective-target ia32 } */
   4 /* { dg-require-effective-target nonpic } */
   5 /* { dg-options "-O2 -fomit-frame-pointer" } */
   6
   7 static int ustrsize (const char *s);
   8 static int (*ucwidth) (int c);
   9 static int (*ugetxc) (const char **s);
  10 static int (*usetc) (char *s, int c);
  11
  12 char *ustrzcat(char *dest, int size, const char *src)
  13 {
  14    int pos = ustrsize(dest);
  15    int c;
  16
  17    size -= pos + ucwidth(0);
  18
  19    while ((c = ugetxc(&src)) != 0) {
  20       size -= ucwidth(c);
  21       if (size < 0)
  22          break;
  23
  24       pos += usetc(dest+pos, c);
  25    }
  26
  27    usetc(dest+pos, 0);
  28
  29    return dest;
  30 }
  31
  32 static int __attribute__((noinline))
  33 ustrsize (const char *s)
  34 {
  35   return 0;
  36 }
  37
  38 static int
  39 ucwidth_ (int c)
  40 {
  41   return 1;
  42 }
  43
  44 static int
  45 ugetxc_ (const char **s)
  46 {
  47   return '\0';
  48 }
  49
  50 static int
  51 usetc_ (char *s, int c)
  52 {
  53   return 1;
  54 }
  55
  56 int
  57 main()
  58 {
  59   ucwidth = ucwidth_;
  60   ugetxc = ugetxc_;
  61   usetc = usetc_;
  62
  63   /* ??? It is impossible to explicitly modify the hard frame pointer.
  64      This will run afoul of code in flow.c that declines to mark regs
  65      in eliminate_regs in regs_ever_used.  Apparently, we have to wait
  66      for reload to decide that it won't need a frame pointer before a
  67      variable can be allocated to %ebp.
  68
  69      So save, restore, and clobber %ebp by hand.  */
  70
  71   asm ("pushl %%ebp\n\t"
  72        "movl $-1, %%ebp\n\t"
  73        "pushl $0\n\t"
  74        "pushl $0\n\t"
  75        "pushl $0\n\t"
  76        "call %P0\n\t"
  77        "addl $12, %%esp\n\t"
  78        "popl %%ebp"
  79        : : "i"(ustrzcat) : "memory" );
  80
  81   return 0;
  82 }