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

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