gcc/testsuite/gcc.dg/pure-2.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -Wsuggest-attribute=pure" } */
   3 /* { dg-add-options bind_pic_locally } */
   4
   5 extern int extern_const(int a) __attribute__ ((pure));
   6 extern int v;
   7
   8 /* Trivial.  */
   9 int
  10 foo1(int a)  /* { dg-bogus "normally" "detect pure candidate" } */
  11 { /* { dg-warning "pure" "detect pure candidate" { target *-*-* } "10" } */
  12   return v;
  13 }
  14
  15 /* Loops known to be normally and extern const calls should be safe.  */
  16 int __attribute__ ((noinline))
  17 foo2(int n)  /* { dg-bogus "normally" "detect pure candidate" } */
  18 { /* { dg-warning "pure" "detect pure candidate" { target *-*-* } "17" } */
  19   int ret = 0;
  20   int i;
  21   for (i=0; i<n; i++)
  22     ret+=extern_const (i);
  23   return ret;
  24 }
  25
  26 /* No warning here; we can work it by ourselves.  */
  27 static int __attribute__ ((noinline))
  28 foo2b(int n)
  29 {
  30   int ret = 0;
  31   int i;
  32   for (i=0; i<n; i++)
  33     ret+=extern_const (i);
  34   return ret;
  35 }
  36
  37 /* Unbounded loops are not safe.  */
  38 static int __attribute__ ((noinline))
  39 foo3(unsigned int n) /* { dg-warning "pure\[^\n\]* normally" "detect pure candidate" } */
  40 {
  41   int ret = 0;
  42   unsigned int i;
  43   for (i=0; extern_const (i+n); n++)
  44     ret+=extern_const (i);
  45   return ret;
  46 }
  47
  48 int
  49 foo4(int n)  /* { dg-warning "pure\[^\n\]* normally" "detect pure candidate" } */
  50 {
  51   return foo3(n) + foo2b(n);
  52 }
  53
  54 int
  55 foo5(int n)  /* { dg-bogus "normally" "detect pure candidate" } */
  56 {  /* { dg-warning "pure" "detect pure candidate" { target *-*-* } "55" } */
  57   return foo2(n);
  58 }