gcc/testsuite/gcc.target/s390/insv-2.c

/* { dg-do compile } */
/* { dg-options "-O3 -march=zEC12 -mzarch" } */

unsigned long
foo1 (unsigned long a, unsigned long b)
{
  return (a << 5) | (b & (((1UL << 5) - 1)));
}

/* This generates very different RTX than foo1.  The output reg (r2)
   matches the unshifted argument.  So it actually is a
   (set (zero_extract a 59 0) b) */
unsigned long
foo2 (unsigned long a, unsigned long b)
{
  return (b << 5) | (a & (((1UL << 5) - 1)));
}

/* risbgn cannot be used when less bits are removed with the mask.  */

unsigned long
foo1b (unsigned long a, unsigned long b)
{
  return (a << 5) | (b & 1);
}

unsigned long
foo2b (unsigned long a, unsigned long b)
{
  return (b << 5) | (a & 1);
}

/* risbgn cannot be used when the masked bits would end up in the
   result since a real OR is required then.  */
unsigned long
foo1c (unsigned long a, unsigned long b)
{
  return (a << 5) | (b & 127);
}

unsigned long
foo2c (unsigned long a, unsigned long b)
{
  return (b << 5) | (a & 127);
}

unsigned long
foo3 (unsigned long a, unsigned long b)
{
#ifdef __s390x__
  return (a << 5) | (b >> 59);
#else
  return (a << 5) | (b >> 27);
#endif
}

unsigned long
foo4 (unsigned long a, unsigned long b)
{
#ifdef __s390x__
  return (b << 5) | (a >> 59);
#else
  return (b << 5) | (a >> 27);
#endif
}

/* risbgn can be used also if there are some bits spared in the middle
   of the two chunks.  */
unsigned long
foo3b (unsigned long a, unsigned long b)
{
#ifdef __s390x__
  return (a << 6) | (b >> 59);
#else
  return (a << 6) | (b >> 27);
#endif
}

unsigned long
foo4b (unsigned long a, unsigned long b)
{
#ifdef __s390x__
  return (b << 6) | (a >> 59);
#else
  return (b << 6) | (a >> 27);
#endif
}

/* One bit of overlap so better don't use risbgn.  */

unsigned long
foo3c (unsigned long a, unsigned long b)
{
#ifdef __s390x__
  return (a << 4) | (b >> 59);
#else
  return (a << 4) | (b >> 27);
#endif
}

unsigned long
foo4c (unsigned long a, unsigned long b)
{
#ifdef __s390x__
  return (b << 4) | (a >> 59);
#else
  return (b << 4) | (a >> 27);
#endif
}

/* The functions foo3, foo4, foo3b, foo4b no longer use risbgn but rosbg instead
   which is slightly worse.  Combine prefers to use the simpler two insn
   combinations possible with rosbg instead of the more complicated three insn
   combinations that result in risbgn.  This problem has been introduced with
   the commit

     S/390: Add patterns for r<nox>sbg instructions.

   (3rd of May, 2016).  This should be fixed some time in the future, but for
   now just adapt the expected result:

   { dg-final { scan-assembler-times "risbgn" 6 { xfail { *-*-* } } } }
   { dg-final { scan-assembler-times "risbgn" 2 } }
*/