rs6000: using li/lis+oris/xoris to build constants

Message ID 20220824081344.70468-1-guojiufu@linux.ibm.com
State New, archived
Headers
Series rs6000: using li/lis+oris/xoris to build constants |

Commit Message

Jiufu Guo Aug. 24, 2022, 8:13 a.m. UTC
  Hi,

PR106708 constaint some constants which can be support by li/lis + oris/xoris.

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'.

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?

BR,
Jeff(Jiufu)


	PR target/106708

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Using li/lis +
	oris/xoris to build constants.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr106708.c: New test.
	* gcc.target/powerpc/pr106708.h: New file.
	* gcc.target/powerpc/pr106708_1.c: New test.

---
 gcc/config/rs6000/rs6000.cc                   | 22 +++++++++++++++++++
 gcc/testsuite/gcc.target/powerpc/pr106708.c   | 10 +++++++++
 gcc/testsuite/gcc.target/powerpc/pr106708.h   |  9 ++++++++
 gcc/testsuite/gcc.target/powerpc/pr106708_1.c | 17 ++++++++++++++
 4 files changed, 58 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.h
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708_1.c
  

Comments

Jiufu Guo Sept. 7, 2022, 7:36 a.m. UTC | #1
Jiufu Guo <guojiufu@linux.ibm.com> writes:

Gentle ping:
https://gcc.gnu.org/pipermail/gcc-patches/2022-August/600189.html

BR,
Jeff(Jiufu)

> Hi,
>
> PR106708 constaint some constants which can be support by li/lis + oris/xoris.
>
> 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'.
>
> 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?
>
> BR,
> Jeff(Jiufu)
>
>
> 	PR target/106708
>
> gcc/ChangeLog:
>
> 	* config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Using li/lis +
> 	oris/xoris to build constants.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/powerpc/pr106708.c: New test.
> 	* gcc.target/powerpc/pr106708.h: New file.
> 	* gcc.target/powerpc/pr106708_1.c: New test.
>
> ---
>  gcc/config/rs6000/rs6000.cc                   | 22 +++++++++++++++++++
>  gcc/testsuite/gcc.target/powerpc/pr106708.c   | 10 +++++++++
>  gcc/testsuite/gcc.target/powerpc/pr106708.h   |  9 ++++++++
>  gcc/testsuite/gcc.target/powerpc/pr106708_1.c | 17 ++++++++++++++
>  4 files changed, 58 insertions(+)
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.c
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.h
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708_1.c
>
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index df491bee2ea..243247fb838 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -10112,6 +10112,7 @@ 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;
> @@ -10137,6 +10138,27 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
>  			gen_rtx_IOR (DImode, copy_rtx (temp),
>  				     GEN_INT (ud1)));
>      }
> +  else if (ud4 == 0 && ud3 == 0 && (ud2 & 0x8000) && !(ud1 & 0x8000))
> +    {
> +      temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
> +
> +      /* li+oris */
> +      emit_move_insn (copy_rtx (temp), GEN_INT (ud1));
> +      emit_move_insn (dest, gen_rtx_IOR (DImode, copy_rtx (temp),
> +					 GEN_INT (ud2 << 16)));
> +    }
> +  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 (copy_rtx (temp), GEN_INT (imm));
> +      emit_move_insn (dest, gen_rtx_XOR (DImode, copy_rtx (temp),
> +					 GEN_INT (orig_c ^ imm)));
> +    }
>    else if (ud3 == 0 && ud4 == 0)
>      {
>        temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.c b/gcc/testsuite/gcc.target/powerpc/pr106708.c
> new file mode 100644
> index 00000000000..6445fa47747
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.c
> @@ -0,0 +1,10 @@
> +/* PR target/106708 */
> +/* { dg-options "-O2 -mdejagnu-cpu=power8" } */
> +/* { dg-do compile { 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..ad07eb30547
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.h
> @@ -0,0 +1,9 @@
> +/* li/lis + oris/xoris */
> +void  __attribute__ ((__noinline__, __noclone__)) foo (long long *arg)
> +{
> +  *arg++ = 0x98765432ULL;
> +  *arg++ = 0xffffffff7cdeab55ULL;
> +  *arg++ = 0xffffffff65430000ULL;
> +}
> +
> +
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708_1.c b/gcc/testsuite/gcc.target/powerpc/pr106708_1.c
> new file mode 100644
> index 00000000000..df65c321f6b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708_1.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;
> +}
  
Kewen.Lin Oct. 20, 2022, 9:29 a.m. UTC | #2
Hi Jeff,

Sorry for late review, some comments are inline.

on 2022/8/24 16:13, Jiufu Guo via Gcc-patches wrote:
> Hi,
> 
> PR106708 constaint some constants which can be support by li/lis + oris/xoris.
> 
> 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'.
> 
> 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.
> 

Maybe it's good to add some explanation on the proposed writing "N(M)"
N continuous bit M, (x for M means either 1 or 0), and not sure if it's
good to use "||" for concatenation just like what ISA uses, the con
is it can be mis-interpreted as logical "or".

Or maybe just expand all the low 32 bits and use "1..." or "0..." for the
high 32 bits.

> 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?
> 
> BR,
> Jeff(Jiufu)
> 
> 
> 	PR target/106708
> 
> gcc/ChangeLog:
> 
> 	* config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Using li/lis +
> 	oris/xoris to build constants.

Nit: Support constants which can be built with li + oris or li/lis + xoris?

> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/powerpc/pr106708.c: New test.
> 	* gcc.target/powerpc/pr106708.h: New file.
> 	* gcc.target/powerpc/pr106708_1.c: New test.
> 
> ---
>  gcc/config/rs6000/rs6000.cc                   | 22 +++++++++++++++++++
>  gcc/testsuite/gcc.target/powerpc/pr106708.c   | 10 +++++++++
>  gcc/testsuite/gcc.target/powerpc/pr106708.h   |  9 ++++++++
>  gcc/testsuite/gcc.target/powerpc/pr106708_1.c | 17 ++++++++++++++
>  4 files changed, 58 insertions(+)
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.c
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.h
>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708_1.c
> 
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index df491bee2ea..243247fb838 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -10112,6 +10112,7 @@ 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;
> @@ -10137,6 +10138,27 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
>  			gen_rtx_IOR (DImode, copy_rtx (temp),
>  				     GEN_INT (ud1)));
>      }
> +  else if (ud4 == 0 && ud3 == 0 && (ud2 & 0x8000) && !(ud1 & 0x8000))
> +    {
> +      temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
> +
> +      /* li+oris */
> +      emit_move_insn (copy_rtx (temp), GEN_INT (ud1));

Nit: in previous discussion on some other patch, copy_rtx is not necessary?

> +      emit_move_insn (dest, gen_rtx_IOR (DImode, copy_rtx (temp),
> +					 GEN_INT (ud2 << 16)));
> +    }

I think this hunk above can be moved to the existing "(ud3 == 0 && ud4 == 0)"
handling branch (as the diff context below), and ud2 & 0x8000 is already
asserted there, it also saves check.

> +  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 (copy_rtx (temp), GEN_INT (imm));
> +      emit_move_insn (dest, gen_rtx_XOR (DImode, copy_rtx (temp),
> +					 GEN_INT (orig_c ^ imm)));
> +    }

Same comment for copy_rtx.

>    else if (ud3 == 0 && ud4 == 0)
>      {
>        temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.c b/gcc/testsuite/gcc.target/powerpc/pr106708.c
> new file mode 100644
> index 00000000000..6445fa47747
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.c
> @@ -0,0 +1,10 @@
> +/* PR target/106708 */
> +/* { dg-options "-O2 -mdejagnu-cpu=power8" } */
> +/* { dg-do compile { target has_arch_ppc64 } } */
> +

Put dg-do as the first line, if you want has_arch_ppc64 to be behind dg-options,
separate it into a dg-require-effective-target.

> +#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..ad07eb30547
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.h
> @@ -0,0 +1,9 @@
> +/* li/lis + oris/xoris */


Nit: /* Test constants which can be built from li + oris and li/lis + xoris.  */

> +void  __attribute__ ((__noinline__, __noclone__)) foo (long long *arg)
> +{
> +  *arg++ = 0x98765432ULL;
> +  *arg++ = 0xffffffff7cdeab55ULL;
> +  *arg++ = 0xffffffff65430000ULL;
> +}
> +
> +
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708_1.c b/gcc/testsuite/gcc.target/powerpc/pr106708_1.c
> new file mode 100644
> index 00000000000..df65c321f6b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708_1.c

Nit: better with name pr106708-run.c?

BR,
Kewen

> @@ -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;
> +}
  
Jiufu Guo Oct. 26, 2022, 2:56 a.m. UTC | #3
"Kewen.Lin" <linkw@linux.ibm.com> writes:

> Hi Jeff,
>
> Sorry for late review, some comments are inline.
>
> on 2022/8/24 16:13, Jiufu Guo via Gcc-patches wrote:
>> Hi,
>> 
>> PR106708 constaint some constants which can be support by li/lis + oris/xoris.
>> 
>> 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'.
>> 
>> 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.
>> 
>
> Maybe it's good to add some explanation on the proposed writing "N(M)"
> N continuous bit M, (x for M means either 1 or 0), and not sure if it's
> good to use "||" for concatenation just like what ISA uses, the con
> is it can be mis-interpreted as logical "or".
>
> Or maybe just expand all the low 32 bits and use "1..." or "0..." for the
> high 32 bits.
>
Great, thanks for sugguestions!
>> 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?
>> 
>> BR,
>> Jeff(Jiufu)
>> 
>> 
>> 	PR target/106708
>> 
>> gcc/ChangeLog:
>> 
>> 	* config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Using li/lis +
>> 	oris/xoris to build constants.
>
> Nit: Support constants which can be built with li + oris or li/lis +
> xoris?
Thanks.
>
>> 
>> gcc/testsuite/ChangeLog:
>> 
>> 	* gcc.target/powerpc/pr106708.c: New test.
>> 	* gcc.target/powerpc/pr106708.h: New file.
>> 	* gcc.target/powerpc/pr106708_1.c: New test.
>> 
>> ---
>>  gcc/config/rs6000/rs6000.cc                   | 22 +++++++++++++++++++
>>  gcc/testsuite/gcc.target/powerpc/pr106708.c   | 10 +++++++++
>>  gcc/testsuite/gcc.target/powerpc/pr106708.h   |  9 ++++++++
>>  gcc/testsuite/gcc.target/powerpc/pr106708_1.c | 17 ++++++++++++++
>>  4 files changed, 58 insertions(+)
>>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.c
>>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708.h
>>  create mode 100644 gcc/testsuite/gcc.target/powerpc/pr106708_1.c
>> 
>> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
>> index df491bee2ea..243247fb838 100644
>> --- a/gcc/config/rs6000/rs6000.cc
>> +++ b/gcc/config/rs6000/rs6000.cc
>> @@ -10112,6 +10112,7 @@ 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;
>> @@ -10137,6 +10138,27 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
>>  			gen_rtx_IOR (DImode, copy_rtx (temp),
>>  				     GEN_INT (ud1)));
>>      }
>> +  else if (ud4 == 0 && ud3 == 0 && (ud2 & 0x8000) && !(ud1 & 0x8000))
>> +    {
>> +      temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
>> +
>> +      /* li+oris */
>> +      emit_move_insn (copy_rtx (temp), GEN_INT (ud1));
>
> Nit: in previous discussion on some other patch, copy_rtx is not
> necessary?
Yeap, thanks!
>
>> +      emit_move_insn (dest, gen_rtx_IOR (DImode, copy_rtx (temp),
>> +					 GEN_INT (ud2 << 16)));
>> +    }
>
> I think this hunk above can be moved to the existing "(ud3 == 0 && ud4 == 0)"
> handling branch (as the diff context below), and ud2 & 0x8000 is already
> asserted there, it also saves check.
Great, thanks for point out this. You are right, this would save some
checking.
>
>> +  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 (copy_rtx (temp), GEN_INT (imm));
>> +      emit_move_insn (dest, gen_rtx_XOR (DImode, copy_rtx (temp),
>> +					 GEN_INT (orig_c ^ imm)));
>> +    }
>
> Same comment for copy_rtx.
>
>>    else if (ud3 == 0 && ud4 == 0)
>>      {
>>        temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
>> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.c b/gcc/testsuite/gcc.target/powerpc/pr106708.c
>> new file mode 100644
>> index 00000000000..6445fa47747
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.c
>> @@ -0,0 +1,10 @@
>> +/* PR target/106708 */
>> +/* { dg-options "-O2 -mdejagnu-cpu=power8" } */
>> +/* { dg-do compile { target has_arch_ppc64 } } */
>> +
>
> Put dg-do as the first line, if you want has_arch_ppc64 to be behind dg-options,
> separate it into a dg-require-effective-target.
OK, thanks!

>
>> +#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..ad07eb30547
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708.h
>> @@ -0,0 +1,9 @@
>> +/* li/lis + oris/xoris */
>
>
> Nit: /* Test constants which can be built from li + oris and li/lis + xoris.  */
>
OK, thanks.
>> +void  __attribute__ ((__noinline__, __noclone__)) foo (long long *arg)
>> +{
>> +  *arg++ = 0x98765432ULL;
>> +  *arg++ = 0xffffffff7cdeab55ULL;
>> +  *arg++ = 0xffffffff65430000ULL;
>> +}
>> +
>> +
>> diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708_1.c b/gcc/testsuite/gcc.target/powerpc/pr106708_1.c
>> new file mode 100644
>> index 00000000000..df65c321f6b
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/pr106708_1.c
>
> Nit: better with name pr106708-run.c?
Ok, thanks!

>
> BR,
> Kewen
>
>> @@ -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;
>> +}
  

Patch

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index df491bee2ea..243247fb838 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -10112,6 +10112,7 @@  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;
@@ -10137,6 +10138,27 @@  rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT c)
 			gen_rtx_IOR (DImode, copy_rtx (temp),
 				     GEN_INT (ud1)));
     }
+  else if (ud4 == 0 && ud3 == 0 && (ud2 & 0x8000) && !(ud1 & 0x8000))
+    {
+      temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
+
+      /* li+oris */
+      emit_move_insn (copy_rtx (temp), GEN_INT (ud1));
+      emit_move_insn (dest, gen_rtx_IOR (DImode, copy_rtx (temp),
+					 GEN_INT (ud2 << 16)));
+    }
+  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 (copy_rtx (temp), GEN_INT (imm));
+      emit_move_insn (dest, gen_rtx_XOR (DImode, copy_rtx (temp),
+					 GEN_INT (orig_c ^ imm)));
+    }
   else if (ud3 == 0 && ud4 == 0)
     {
       temp = !can_create_pseudo_p () ? dest : gen_reg_rtx (DImode);
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708.c b/gcc/testsuite/gcc.target/powerpc/pr106708.c
new file mode 100644
index 00000000000..6445fa47747
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106708.c
@@ -0,0 +1,10 @@ 
+/* PR target/106708 */
+/* { dg-options "-O2 -mdejagnu-cpu=power8" } */
+/* { dg-do compile { 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..ad07eb30547
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106708.h
@@ -0,0 +1,9 @@ 
+/* li/lis + oris/xoris */
+void  __attribute__ ((__noinline__, __noclone__)) foo (long long *arg)
+{
+  *arg++ = 0x98765432ULL;
+  *arg++ = 0xffffffff7cdeab55ULL;
+  *arg++ = 0xffffffff65430000ULL;
+}
+
+
diff --git a/gcc/testsuite/gcc.target/powerpc/pr106708_1.c b/gcc/testsuite/gcc.target/powerpc/pr106708_1.c
new file mode 100644
index 00000000000..df65c321f6b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr106708_1.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;
+}