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-skip-if "" { i?86-*-* } { "-m64" "-fpic" "-fPIC" } { "" } } */
   4 /* { dg-options "-O2 -fomit-frame-pointer" } */
   5
   6 static int ustrsize (const char *s);
   7 static int (*ucwidth) (int c);
   8 static int (*ugetxc) (const char **s);
   9 static int (*usetc) (char *s, int c);
  10
  11 char *ustrzcat(char *dest, int size, const char *src)
  12 {
  13    int pos = ustrsize(dest);
  14    int c;
  15
  16    size -= pos + ucwidth(0);
  17
  18    while ((c = ugetxc(&src)) != 0) {
  19       size -= ucwidth(c);
  20       if (size < 0)
  21          break;
  22
  23       pos += usetc(dest+pos, c);
  24    }
  25
  26    usetc(dest+pos, 0);
  27
  28    return dest;
  29 }
  30
  31 static int __attribute__((noinline))
  32 ustrsize (const char *s)
  33 {
  34   return 0;
  35 }
  36
  37 static int
  38 ucwidth_ (int c)
  39 {
  40   return 1;
  41 }
  42
  43 static int
  44 ugetxc_ (const char **s)
  45 {
  46   return '\0';
  47 }
  48
  49 static int
  50 usetc_ (char *s, int c)
  51 {
  52   return 1;
  53 }
  54
  55 int
  56 main()
  57 {
  58   ucwidth = ucwidth_;
  59   ugetxc = ugetxc_;
  60   usetc = usetc_;
  61
  62   /* ??? It is impossible to explicitly modify the hard frame pointer.
  63      This will run afoul of code in flow.c that declines to mark regs
  64      in eliminate_regs in regs_ever_used.  Apparently, we have to wait
  65      for reload to decide that it won't need a frame pointer before a
  66      variable can be allocated to %ebp.
  67
  68      So save, restore, and clobber %ebp by hand.  */
  69
  70   asm ("pushl %%ebp\n\t"
  71        "movl $-1, %%ebp\n\t"
  72        "pushl $0\n\t"
  73        "pushl $0\n\t"
  74        "pushl $0\n\t"
  75        "call %P0\n\t"
  76        "addl $12, %%esp\n\t"
  77        "popl %%ebp"
  78        : : "i"(ustrzcat) : "memory" );
  79
  80   return 0;
  81 }