Re: [PATCH V2] rs6000: Support to build constants by li/lis+oris/xoris

["Kewen.Lin" <linkw@linux.ibm.com>]

Hi Jeff,

Sorry for the late reply.

on 2022/10/26 19:40, Jiufu Guo wrote:
> Hi,
> 
> PR106708 constaint some constants which can be support by li/lis + oris/xoris.
           ~~~~~~~~ typo?

for "li/lis + oris/xoris", I interpreted it into four combinations:

   li + oris, lis + oris, li + xoris, lis + xoris.

not sure just me interpreting like that, but the actual combinations
which this patch adopts are:

   li + oris, li + xoris, lis + xoris.

It's a bit off, but not a big deal, up to you to reword it or not.  :)

> 
> For constant C:
> if '(c & 0xFFFFFFFF80008000ULL) == 0x80000000ULL' or say:
> 32(0) || 1(1) || 15(x) || 1(0) || 15(x), we could use li+oris to
> build constant 'C'.
> Here N(M) means N continuous bit M, x for M means it is ok for either
> 1 or 0; '||' means concatenation.
> 
> if '(c & 0xFFFFFFFF00008000ULL) == 0xFFFFFFFF00008000ULL' or say:
> 32(1) || 16(x) || 1(1) || 15(x), using li+xoris would be ok.
> 
> if '(c & 0xFFFFFFFF0000FFFFULL) == 0xFFFFFFFF00000000' or say:
> 32(1) || 1(0) || 15(x) || 16(0), using lis+xoris would be ok.
> 
> This patch update rs6000_emit_set_long_const to support these forms.
> Bootstrap and regtest pass on ppc64 and ppc64le.
> 
> Is this ok for trunk?

This updated version looks good to me, but I'd leave it to Segher for the
final say.  Thanks!

BR,
Kewen

> 
> BR,
> Jeff(Jiufu)
> 
> 
> 	PR target/106708
> 
> gcc/ChangeLog:
> 
> 	* config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Support
> 	constants which can be built with li + oris or li/lis + xoris.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/powerpc/pr106708-run.c: New test.
> 	* gcc.target/powerpc/pr106708.c: New test.
> 	* gcc.target/powerpc/pr106708.h: New file.
> 
> ---
>  gcc/config/rs6000/rs6000.cc                   | 41 ++++++++++++++-----
>  .../gcc.target/powerpc/pr106708-run.c         | 17 ++++++++
>  gcc/testsuite/gcc.target/powerpc/pr106708.c   | 12 ++++++
>  gcc/testsuite/gcc.target/powerpc/pr106708.h   |  9 ++++
>  4 files changed, 69 insertions(+), 10 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708-run.c
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.c
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.h
> 
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index d2743f7bce6..9b7a51f052d 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -10228,6 +10228,7 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
>  {
>    rtx temp;
>    HOST_WIDE_INT ud1, ud2, ud3, ud4;
> +  HOST_WIDE_INT orig_c = c;
> 
>    ud1 = c & 0xffff;
>    c = c >> 16;
> @@ -10253,21 +10254,41 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
>  			gen_rtx_IOR (DImode, copy_rtx (temp),
>  				     GEN_INT (ud1)));
>      }
> +  else if ((ud4 == 0xffff && ud3 == 0xffff)
> +	   && ((ud1 & 0x8000) || (ud1 == 0 && !(ud2 & 0x8000))))
> +    {
> +      temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
> +
> +      HOST_WIDE_INT imm = (ud1 & 0x8000) ? ((ud1 ^ 0x8000) - 0x8000)
> +					 : ((ud2 << 16) - 0x80000000);
> +      /* li/lis + xoris */
> +      emit_move_insn (temp, GEN_INT (imm));
> +      emit_move_insn (dest, gen_rtx_XOR (DImode, temp,
> +					 GEN_INT (orig_c ^ imm)));
> +    }
>    else if (ud3 == 0 && ud4 == 0)
>      {
>        temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
> 
>        gcc_assert (ud2 & 0x8000);
> -      emit_move_insn (copy_rtx (temp),
> -		      GEN_INT (((ud2 << 16) ^ 0x80000000) - 0x80000000));
> -      if (ud1 != 0)
> -	emit_move_insn (copy_rtx (temp),
> -			gen_rtx_IOR (DImode, copy_rtx (temp),
> -				     GEN_INT (ud1)));
> -      emit_move_insn (dest,
> -		      gen_rtx_ZERO_EXTEND (DImode,
> -					   gen_lowpart (SImode,
> -							copy_rtx (temp))));
> +
> +      if (!(ud1 & 0x8000))
> +	{
> +	  /* li+oris */
> +	  emit_move_insn (temp, GEN_INT (ud1));
> +	  emit_move_insn (dest,
> +			  gen_rtx_IOR (DImode, temp, GEN_INT (ud2 << 16)));
> +	}
> +      else
> +	{
> +	  emit_move_insn (temp,
> +			  GEN_INT (((ud2 << 16) ^ 0x80000000) - 0x80000000));
> +	  if (ud1 != 0)
> +	    emit_move_insn (temp, gen_rtx_IOR (DImode, temp, GEN_INT (ud1)));
> +	  emit_move_insn (dest,
> +			  gen_rtx_ZERO_EXTEND (DImode,
> +					       gen_lowpart (SImode, temp)));
> +	}
>      }
>    else if (ud1 == ud3 && ud2 == ud4)
>      {
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708-run.c b/gcc/testsuite/gcc.target/powerpc/pr106708-run.c
> new file mode 100644
> index 00000000000..df65c321f6b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708-run.c
> @@ -0,0 +1,17 @@
> +/* PR target/106708 */
> +/* { dg-do run } */
> +/* { dg-options "-O2" } */
> +
> +#include "pr106708.h"
> +
> +long long arr[] = {0x98765432ULL, 0xffffffff7cdeab55ULL, 0xffffffff65430000ULL};
> +int
> +main ()
> +{
> +  long long a[3];
> +
> +  foo (a);
> +  if (__builtin_memcmp (a, arr, sizeof (arr)) != 0)
> +    __builtin_abort ();
> +  return 0;
> +}
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.c b/gcc/testsuite/gcc.target/powerpc/pr106708.c
> new file mode 100644
> index 00000000000..ebd9ea88993
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.c
> @@ -0,0 +1,12 @@
> +/* PR target/106708 */
> +/* { dg-do compile } } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power8" } */
> +/* { dg-require-effective-target has_arch_ppc64 } */
> +
> +
> +#include "pr106708.h"
> +
> +/* { dg-final { scan-assembler-times {\mli\M} 2 } } */
> +/* { dg-final { scan-assembler-times {\mlis\M} 1 } } */
> +/* { dg-final { scan-assembler-times {\moris\M} 1 } } */
> +/* { dg-final { scan-assembler-times {\mxoris\M} 2 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.h b/gcc/testsuite/gcc.target/powerpc/pr106708.h
> new file mode 100644
> index 00000000000..42526a70892
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.h
> @@ -0,0 +1,9 @@
> +/* Test constants which can be built by li/lis + oris/xoris */
> +void  __attribute__ ((__noinline__, __noclone__)) foo (long long *arg)
> +{
> +  *arg++ = 0x98765432ULL;
> +  *arg++ = 0xffffffff7cdeab55ULL;
> +  *arg++ = 0xffffffff65430000ULL;
> +}
> +
> +