gcc/testsuite/gcc.c-torture/execute/pr28982a.c

   1 /* PR rtl-optimization/28982.  Function foo() does the equivalent of:
   2
   3      float tmp_results[NVARS];
   4      for (int i = 0; i < NVARS; i++)
   5        {
   6          int inc = incs[i];
   7          float *ptr = ptrs[i], result = 0;
   8          for (int j = 0; j < n; j++)
   9            result += *ptr, ptr += inc;
  10          tmp_results[i] = result;
  11        }
  12      memcpy (results, tmp_results, sizeof (results));
  13
  14    but without the outermost loop.  The idea is to create high register
  15    pressure and ensure that some INC and PTR variables are spilled.
  16
  17    On ARM targets, sequences like "result += *ptr, ptr += inc" can
  18    usually be implemented using (mem (post_modify ...)), and we do
  19    indeed create such MEMs before reload for this testcase.  However,
  20    (post_modify ...) is not a valid address for coprocessor loads, so
  21    for -mfloat-abi=softfp, reload reloads the POST_MODIFY into a base
  22    register.  GCC did not deal correctly with cases where the base and
  23    index of the POST_MODIFY are themselves reloaded.  */
  24 #define NITER 4
  25 #define NVARS 20
  26 #define MULTI(X) \
  27   X( 0), X( 1), X( 2), X( 3), X( 4), X( 5), X( 6), X( 7), X( 8), X( 9), \
  28   X(10), X(11), X(12), X(13), X(14), X(15), X(16), X(17), X(18), X(19)
  29
  30 #define DECLAREI(INDEX) inc##INDEX = incs[INDEX]
  31 #define DECLAREF(INDEX) *ptr##INDEX = ptrs[INDEX], result##INDEX = 0
  32 #define LOOP(INDEX) result##INDEX += *ptr##INDEX, ptr##INDEX += inc##INDEX
  33 #define COPYOUT(INDEX) results[INDEX] = result##INDEX
  34
  35 float *ptrs[NVARS];
  36 float results[NVARS];
  37 int incs[NVARS];
  38
  39 void __attribute__((noinline))
  40 foo (int n)
  41 {
  42   int MULTI (DECLAREI);
  43   float MULTI (DECLAREF);
  44   while (n--)
  45     MULTI (LOOP);
  46   MULTI (COPYOUT);
  47 }
  48
  49 float input[NITER * NVARS];
  50
  51 int
  52 main (void)
  53 {
  54   int i;
  55
  56   for (i = 0; i < NVARS; i++)
  57     ptrs[i] = input + i, incs[i] = i;
  58   for (i = 0; i < NITER * NVARS; i++)
  59     input[i] = i;
  60   foo (NITER);
  61   for (i = 0; i < NVARS; i++)
  62     if (results[i] != i * NITER * (NITER + 1) / 2)
  63       return 1;
  64   return 0;
  65 }