gcc/testsuite/gcc.dg/simulate-thread/speculative-store-3.c

   1 /* { dg-do link } */
   2 /* { dg-options "--param allow-store-data-races=0 -O2" } */
   3 /* { dg-final { simulate-thread } } */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7
   8 #include "simulate-thread.h"
   9
  10 /* Test distilled from PR52558.  */
  11
  12 int g_1 = 1;
  13 int g_2 = 0, insns = 0;
  14 int f;
  15
  16 /* Test that g_2 is not written to unless !g_1.  */
  17
  18 __attribute__((noinline))
  19 int funky()
  20 {
  21   int l;
  22   for (l = 0; l != 4; l++)
  23     {
  24       if (g_1)
  25         {
  26           /* g_1 is globally true so we should always execute here,
  27              thus never writing to g_2 under any circumstance in this
  28              code path.  */
  29           return l;
  30         }
  31       for (g_2 = 0; g_2 >= 26; ++g_2)
  32         ;
  33     }
  34   return 999;
  35 }
  36
  37 int simulate_thread_final_verify ()
  38 {
  39   /* If g_2 != insns, someone must have cached `g_2' and stored a
  40      racy value into it.  */
  41   if (g_2 != insns)
  42     {
  43       printf("FAIL: g_2 was incorrectly cached\n");
  44       return 1;
  45     }
  46   return 0;
  47 }
  48
  49 void simulate_thread_other_threads ()
  50 {
  51   ++insns;
  52   ++g_2;
  53 }
  54
  55 int simulate_thread_step_verify ()
  56 {
  57   return 0;
  58 }
  59
  60 __attribute__((noinline))
  61 void simulate_thread_main()
  62 {
  63   f = funky();
  64 }
  65
  66 int main()
  67 {
  68   simulate_thread_main ();
  69   simulate_thread_done ();
  70   return 0;
  71 }