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

[Jiufu Guo <guojiufu@linux.ibm.com>]

Hi Kewen,

Thanks a lot for your insight comments!

"Kewen.Lin" <linkw@linux.ibm.com> writes:

> 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?
Oh, 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.  :)
Oh, thanks! I will update to use "li/lis + xoris" or "li + oris" to
avoid confuse.
>
>> 
>> 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!

Thanks!

BR,
Jeff (Jiufu)
>
> 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;
>> +}
>> +
>> +