gcc/testsuite/gcc.dg/pr30957-1.c

   1 /* { dg-do run } */
   2 /* We don't (and don't want to) perform this optimisation on soft-float targets,
   3    where each addition is a library call.  /
   4 /* { dg-require-effective-target hard_float } */
   5 /* -fassociative-math requires -fno-trapping-math and -fno-signed-zeros. */
   6 /* { dg-options "-O2 -funroll-loops -fassociative-math -fno-trapping-math -fno-signed-zeros -fvariable-expansion-in-unroller -fdump-rtl-loop2_unroll" } */
   7
   8 extern void abort (void);
   9 extern void exit (int);
  10
  11 float __attribute__((noinline))
  12 foo (float d, int n)
  13 {
  14   unsigned i;
  15   float accum = d;
  16
  17   for (i = 0; i < n; i++)
  18     accum += d;
  19
  20   return accum;
  21 }
  22
  23 int
  24 main ()
  25 {
  26   /* When compiling standard compliant we expect foo to return -0.0.  But the
  27      variable expansion during unrolling optimization (for this testcase enabled
  28      by non-compliant -fassociative-math) instantiates copy(s) of the
  29      accumulator which it initializes with +0.0.  Hence we expect that foo
  30      returns +0.0.  */
  31   if (__builtin_copysignf (1.0, foo (0.0 / -5.0, 10)) != 1.0)
  32     abort ();
  33   exit (0);
  34 }
  35
  36 /* { dg-final { scan-rtl-dump "Expanding Accumulator" "loop2_unroll" } } */