Hi Jeff,
on 2023/12/6 13:24, Jiufu Guo wrote:
> Hi,
>
> For constant building e.g. r120=0x66666666, which does not fit 'li or lis',
> 'pli' is used to build this constant via 'emit_move_insn'.
>
> While for a complicated constant, e.g. 0x6666666666666666ULL, when using
> 'rs6000_emit_set_long_const' to split the constant recursively, it fails to
> use 'pli' to build the half part constant: 0x66666666.
>
> 'rs6000_emit_set_long_const' could be updated to use 'pli' to build half
> part of the constant when necessary. For example: 0x6666666666666666ULL,
> "pli 3,1717986918; rldimi 3,3,32,0" can be used.
>
> Compare with previous:
> https://gcc.gnu.org/pipermail/gcc-patches/2023-November/636567.html
> This verion is refreshed and added with a new testcase.
>
> Bootstrap®test pass on ppc64{,le}.
> Is this ok for trunk?
>
> BR,
> Jeff (Jiufu Guo)
>
> gcc/ChangeLog:
>
> * config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Add code to use
> pli for 34bit constant.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/powerpc/const_split_pli.c: New test.
Nit: Now we have:
gcc/testsuite/gcc.target/powerpc/const-build.c
gcc/testsuite/gcc.target/powerpc/const_anchors.c
gcc/testsuite/gcc.target/powerpc/const-compare.c
I prefer the name of this new case is like const-build-1.c
(put a detailed comment inside) or const-build-split-pli.c,
to align with the existing.
>
> ---
> gcc/config/rs6000/rs6000.cc | 7 +++++++
> gcc/testsuite/gcc.target/powerpc/const_split_pli.c | 9 +++++++++
> 2 files changed, 16 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/powerpc/const_split_pli.c
>
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index dbdc72dce5d..2e074a21a05 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -10509,6 +10509,13 @@ rs6000_emit_set_long_const (rtx dest, HOST_WIDE_INT
> c, int *num_insns)
> GEN_INT (0xffffffff)));
> };
>
> + if (TARGET_PREFIXED && SIGNED_INTEGER_34BIT_P (c))
> + {
> + /* li/lis/pli */
> + count_or_emit_insn (dest, GEN_INT (c));
> + return;
> + }
> +
> if ((ud4 == 0xffff && ud3 == 0xffff && ud2 == 0xffff && (ud1 & 0x8000))
> || (ud4 == 0 && ud3 == 0 && ud2 == 0 && !(ud1 & 0x8000)))
> {
> diff --git a/gcc/testsuite/gcc.target/powerpc/const_split_pli.c
> b/gcc/testsuite/gcc.target/powerpc/const_split_pli.c
> new file mode 100644
> index 00000000000..626c93084aa
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/const_split_pli.c
> @@ -0,0 +1,9 @@
> +/* { dg-do compile { target lp64 } } */
> +/* { dg-options "-O2" } */
It needs -mdejagnu-cpu=power10 as well.
> +/* { dg-require-effective-target power10_ok } */
> +
> +unsigned long long msk66() { return 0x6666666666666666ULL; }
> +
> +/* { dg-final { scan-assembler-times {\mpli\M} 1 } } */
> +/* { dg-final { scan-assembler-not {\mli\M} } } */
> +/* { dg-final { scan-assembler-not {\mlis\M} } } */
OK for trunk with the above nits tweaked, thanks!
BR,
Kewen
