Hi Mike,
on 2024/1/6 07:35, Michael Meissner wrote:
> This patch implements support for a potential future PowerPC cpu. Features
> added with -mcpu=future, may or may not be added to new PowerPC processors.
>
> This patch adds support for the -mcpu=future option. If you use -mcpu=future,
> the macro __ARCH_PWR_FUTURE__ is defined, and the assembler .machine directive
> "future" is used. Future patches in this series will add support for new
> instructions that may be present in future PowerPC processors.
>
> This particular patch does not any new features. It exists as a ground work
> for future patches to support for a possible PowerPC processor in the future.
>
> This patch does not implement any differences in tuning when -mcpu=future is
> used compared to -mcpu=power10. If -mcpu=future is used, GCC will use power10
> tuning. If you explicitly use -mtune=future, you will get a warning that
> -mtune=future is not supported, and default tuning will be set for power10.
>
> The patches have been tested on both little and big endian systems. Can I
> check
> it into the master branch?
>
> 2024-01-05 Michael Meissner <meiss...@linux.ibm.com>
>
> gcc/
>
> * config/rs6000/rs6000-c.cc (rs6000_target_modify_macros): Define
> __ARCH_PWR_FUTURE__ if -mcpu=future.
> * config/rs6000/rs6000-cpus.def (ISA_FUTURE_MASKS): New macro.
> (POWERPC_MASKS): Add -mcpu=future support.
> * config/rs6000/rs6000-opts.h (enum processor_type): Add
> PROCESSOR_FUTURE.
> * config/rs6000/rs6000-tables.opt: Regenerate.
> * config/rs6000/rs6000.cc (rs600_cpu_index_lookup): New helper
> function.
> (rs6000_option_override_internal): Make -mcpu=future set
> -mtune=power10. If the user explicitly uses -mtune=future, give a
> warning and reset the tuning to power10.
> (rs6000_option_override_internal): Use power10 costs for future
> machine.
> (rs6000_machine_from_flags): Add support for -mcpu=future.
> (rs6000_opt_masks): Likewise.
> * config/rs6000/rs6000.h (ASM_CPU_SUPPORT): Likewise.
> * config/rs6000/rs6000.md (cpu attribute): Likewise.
> * config/rs6000/rs6000.opt (-mfuture): New undocumented debug switch.
> * doc/invoke.texi (IBM RS/6000 and PowerPC Options): Document
> -mcpu=future.
> ---
> gcc/config/rs6000/rs6000-c.cc | 2 +
> gcc/config/rs6000/rs6000-cpus.def | 6 +++
> gcc/config/rs6000/rs6000-opts.h | 4 +-
> gcc/config/rs6000/rs6000-tables.opt | 3 ++
> gcc/config/rs6000/rs6000.cc | 58 ++++++++++++++++++++++++-----
> gcc/config/rs6000/rs6000.h | 1 +
> gcc/config/rs6000/rs6000.md | 2 +-
> gcc/config/rs6000/rs6000.opt | 4 ++
> gcc/doc/invoke.texi | 2 +-
> 9 files changed, 69 insertions(+), 13 deletions(-)
>
> diff --git a/gcc/config/rs6000/rs6000-c.cc b/gcc/config/rs6000/rs6000-c.cc
> index ce0b14a8d37..f2fb5bef678 100644
> --- a/gcc/config/rs6000/rs6000-c.cc
> +++ b/gcc/config/rs6000/rs6000-c.cc
> @@ -447,6 +447,8 @@ rs6000_target_modify_macros (bool define_p, HOST_WIDE_INT
> flags)
> rs6000_define_or_undefine_macro (define_p, "_ARCH_PWR9");
> if ((flags & OPTION_MASK_POWER10) != 0)
> rs6000_define_or_undefine_macro (define_p, "_ARCH_PWR10");
> + if ((flags & OPTION_MASK_FUTURE) != 0)
> + rs6000_define_or_undefine_macro (define_p, "_ARCH_PWR_FUTURE");
> if ((flags & OPTION_MASK_SOFT_FLOAT) != 0)
> rs6000_define_or_undefine_macro (define_p, "_SOFT_FLOAT");
> if ((flags & OPTION_MASK_RECIP_PRECISION) != 0)
> diff --git a/gcc/config/rs6000/rs6000-cpus.def
> b/gcc/config/rs6000/rs6000-cpus.def
> index d28cc87eb2a..8754635f3d9 100644
> --- a/gcc/config/rs6000/rs6000-cpus.def
> +++ b/gcc/config/rs6000/rs6000-cpus.def
> @@ -88,6 +88,10 @@
> | OPTION_MASK_POWER10 \
> | OTHER_POWER10_MASKS)
>
> +/* Flags for a potential future processor that may or may not be delivered.
> */
> +#define ISA_FUTURE_MASKS (ISA_3_1_MASKS_SERVER \
> + | OPTION_MASK_FUTURE)
> +
Nit: Named as "ISA_FUTURE_MASKS_SERVER" seems more accurate as it's constituted
with ISA_3_1_MASKS_**SERVER** ...
> /* Flags that need to be turned off if -mno-power9-vector. */
> #define OTHER_P9_VECTOR_MASKS (OPTION_MASK_FLOAT128_HW
> \
> | OPTION_MASK_P9_MINMAX)
> @@ -135,6 +139,7 @@
> | OPTION_MASK_LOAD_VECTOR_PAIR \
> | OPTION_MASK_POWER10 \
> | OPTION_MASK_P10_FUSION \
> + | OPTION_MASK_FUTURE \
> | OPTION_MASK_HTM \
> | OPTION_MASK_ISEL \
> | OPTION_MASK_MFCRF \
> @@ -267,3 +272,4 @@ RS6000_CPU ("powerpc64", PROCESSOR_POWERPC64,
> OPTION_MASK_PPC_GFXOPT
> RS6000_CPU ("powerpc64le", PROCESSOR_POWER8, MASK_POWERPC64
> | ISA_2_7_MASKS_SERVER | OPTION_MASK_HTM)
> RS6000_CPU ("rs64", PROCESSOR_RS64A, OPTION_MASK_PPC_GFXOPT | MASK_POWERPC64)
> +RS6000_CPU ("future", PROCESSOR_FUTURE, MASK_POWERPC64 | ISA_FUTURE_MASKS)
..., then this need to be updated accordingly.
> diff --git a/gcc/config/rs6000/rs6000-opts.h b/gcc/config/rs6000/rs6000-opts.h
> index 33fd0efc936..25890ae3034 100644
> --- a/gcc/config/rs6000/rs6000-opts.h
> +++ b/gcc/config/rs6000/rs6000-opts.h
> @@ -67,7 +67,9 @@ enum processor_type
> PROCESSOR_MPCCORE,
> PROCESSOR_CELL,
> PROCESSOR_PPCA2,
> - PROCESSOR_TITAN
> + PROCESSOR_TITAN,
> +
Nit: unintentional empty line?
> + PROCESSOR_FUTURE
> };
>
>
> diff --git a/gcc/config/rs6000/rs6000-tables.opt
> b/gcc/config/rs6000/rs6000-tables.opt
> index 65f46709716..97fa98a2e65 100644
> --- a/gcc/config/rs6000/rs6000-tables.opt
> +++ b/gcc/config/rs6000/rs6000-tables.opt
> @@ -197,3 +197,6 @@ Enum(rs6000_cpu_opt_value) String(powerpc64le) Value(55)
> EnumValue
> Enum(rs6000_cpu_opt_value) String(rs64) Value(56)
>
> +EnumValue
> +Enum(rs6000_cpu_opt_value) String(future) Value(57)
> +
> diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
> index 5a7e00b03d1..bc509399cf6 100644
> --- a/gcc/config/rs6000/rs6000.cc
> +++ b/gcc/config/rs6000/rs6000.cc
> @@ -1809,6 +1809,18 @@ rs6000_cpu_name_lookup (const char *name)
> return -1;
> }
>
> +/* Look up the index for a specific processor. */
> +
> +static int
> +rs600_cpu_index_lookup (enum processor_type processor)
s/rs600_cpu_index_lookup/rs6000_cpu_index_lookup/
> +{
> + for (size_t i = 0; i < ARRAY_SIZE (processor_target_table); i++)
> + if (processor_target_table[i].processor == processor)
> + return i;
> +
> + return -1;
> +}
Nit: Since this is given with a valid enum processor_type, I think it should
never return -1? If so, may be more clear with gcc_unreachable () or adjust
with initial -1, break when hits and assert it's not -1.
> +
>
> /* Return number of consecutive hard regs needed starting at reg REGNO
> to hold something of mode MODE.
> @@ -3756,23 +3768,45 @@ rs6000_option_override_internal (bool global_init_p)
> rs6000_isa_flags &= ~OPTION_MASK_POWERPC64;
> #endif
>
> + /* At the moment, we don't have explict -mtune=future support. If the user
Nit: s/explict/explicit/
> + explicitly tried to use -mtune=future, give a warning. If not, use the
Nit: s/tried/tries/?
> + power10 tuning until future tuning is added. */
> if (rs6000_tune_index >= 0)
> - tune_index = rs6000_tune_index;
> + {
> + enum processor_type cur_proc
> + = processor_target_table[rs6000_tune_index].processor;
> +
> + if (cur_proc == PROCESSOR_FUTURE)
> + {
> + static bool issued_future_tune_warning = false;
> + if (!issued_future_tune_warning)
> + {
> + issued_future_tune_warning = true;
This seems to ensure we only warn this once, but I noticed that in rs6000/
only some OPT_Wpsabi related warnings adopt this way, I wonder if we don't
restrict it like this, for a tiny simple case, how many times it would warn?
> + warning (0, "%qs is not currently supported", "-mtune=future");
> + }
> +> + rs6000_tune_index = rs600_cpu_index_lookup (PROCESSOR_POWER10);
> + }
> + tune_index = rs6000_tune_index;
> + }
> else if (cpu_index >= 0)
> - rs6000_tune_index = tune_index = cpu_index;
> + {
> + enum processor_type cur_cpu
> + = processor_target_table[cpu_index].processor;
> +
> + rs6000_tune_index = tune_index
> + = (cur_cpu == PROCESSOR_FUTURE
> + ? rs600_cpu_index_lookup (PROCESSOR_POWER10)
s/rs600_cpu_index_lookup/rs6000_cpu_index_lookup/
> + : cpu_index);
> + }
> else
> {
> - size_t i;
> enum processor_type tune_proc
> = (TARGET_POWERPC64 ? PROCESSOR_DEFAULT64 : PROCESSOR_DEFAULT);
>
> - tune_index = -1;
> - for (i = 0; i < ARRAY_SIZE (processor_target_table); i++)
> - if (processor_target_table[i].processor == tune_proc)
> - {
> - tune_index = i;
> - break;
> - }
> + tune_index = rs600_cpu_index_lookup (tune_proc == PROCESSOR_FUTURE
> + ? PROCESSOR_POWER10
> + : tune_proc);
This part looks useless, as tune_proc is impossible to be PROCESSOR_FUTURE.
> }
Maybe re-structure the above into:
bool explicit_tune = false;
if (rs6000_tune_index >= 0)
{
tune_index = rs6000_tune_index;
explicit_tune = true;
}
else if (cpu_index >= 0)
// as before
rs6000_tune_index = tune_index = cpu_index;
else
{
//as before
...
}
// Check tune_index here instead.
if (processor_target_table[tune_index].processor == PROCESSOR_FUTURE)
{
tune_index = rs6000_cpu_index_lookup (PROCESSOR_POWER10);
if (explicit_tune)
warn ...
}
// as before
rs6000_tune = processor_target_table[tune_index].processor;
>
> if (cpu_index >= 0)
> @@ -4785,6 +4819,7 @@ rs6000_option_override_internal (bool global_init_p)
> break;
>
> case PROCESSOR_POWER10:
> + case PROCESSOR_FUTURE:
> rs6000_cost = &power10_cost;
> break;
>
> @@ -5944,6 +5979,8 @@ rs6000_machine_from_flags (void)
> /* Disable the flags that should never influence the .machine selection.
> */
> flags &= ~(OPTION_MASK_PPC_GFXOPT | OPTION_MASK_PPC_GPOPT |
> OPTION_MASK_ISEL);
>
> + if ((flags & (ISA_FUTURE_MASKS & ~ISA_3_1_MASKS_SERVER)) != 0)
> + return "future";
> if ((flags & (ISA_3_1_MASKS_SERVER & ~ISA_3_0_MASKS_SERVER)) != 0)
> return "power10";
> if ((flags & (ISA_3_0_MASKS_SERVER & ~ISA_2_7_MASKS_SERVER)) != 0)
> @@ -24500,6 +24537,7 @@ static struct rs6000_opt_mask const
> rs6000_opt_masks[] =
> { "float128-hardware", OPTION_MASK_FLOAT128_HW, false, true },
> { "fprnd", OPTION_MASK_FPRND, false, true },
> { "power10", OPTION_MASK_POWER10, false,
> true },
> + { "future", OPTION_MASK_FUTURE, false,
> true },
> { "hard-dfp", OPTION_MASK_DFP, false,
> true },
> { "htm", OPTION_MASK_HTM, false, true },
> { "isel", OPTION_MASK_ISEL, false, true },
> diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
> index 2291fe8d3a3..43209f9a6e7 100644
> --- a/gcc/config/rs6000/rs6000.h
> +++ b/gcc/config/rs6000/rs6000.h
> @@ -163,6 +163,7 @@
> mcpu=e5500: -me5500; \
> mcpu=e6500: -me6500; \
> mcpu=titan: -mtitan; \
> + mcpu=future: -mfuture; \
> !mcpu*: %{mpower9-vector: -mpower9; \
> mpower8-vector|mcrypto|mdirect-move|mhtm: -mpower8; \
> mvsx: -mpower7; \
I think we should also update asm_names in driver-rs6000.cc.
The others look good to me, thanks!
BR,
Kewen
> diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
> index 969d34b69e6..a125fd8fc99 100644
> --- a/gcc/config/rs6000/rs6000.md
> +++ b/gcc/config/rs6000/rs6000.md
> @@ -351,7 +351,7 @@ (define_attr "cpu"
> ppc403,ppc405,ppc440,ppc476,
>
> ppc8540,ppc8548,ppce300c2,ppce300c3,ppce500mc,ppce500mc64,ppce5500,ppce6500,
> power4,power5,power6,power7,power8,power9,power10,
> - rs64a,mpccore,cell,ppca2,titan"
> + rs64a,mpccore,cell,ppca2,titan,future"
> (const (symbol_ref "(enum attr_cpu) rs6000_tune")))
>
> ;; The ISA we implement.
> diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
> index 60b923f5e4b..775ba830eac 100644
> --- a/gcc/config/rs6000/rs6000.opt
> +++ b/gcc/config/rs6000/rs6000.opt
> @@ -628,6 +628,10 @@ mieee128-constant
> Target Var(TARGET_IEEE128_CONSTANT) Init(1) Save
> Generate (do not generate) code that uses the LXVKQ instruction.
>
> +mfuture
> +Target Undocumented Mask(FUTURE) Var(rs6000_isa_flags)
> +Generate (do not generate) future instructions.
> +
> ; Documented parameters
>
> -param=rs6000-vect-unroll-limit=
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index d71583853f0..0e817ee923a 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -30423,7 +30423,7 @@ Supported values for @var{cpu_type} are @samp{401},
> @samp{403},
> @samp{titan}, @samp{power3}, @samp{power4}, @samp{power5}, @samp{power5+},
> @samp{power6}, @samp{power6x}, @samp{power7}, @samp{power8},
> @samp{power9}, @samp{power10}, @samp{powerpc}, @samp{powerpc64},
> -@samp{powerpc64le}, @samp{rs64}, and @samp{native}.
> +@samp{powerpc64le}, @samp{rs64}, @samp{future}, and @samp{native}.
>
> @option{-mcpu=powerpc}, @option{-mcpu=powerpc64}, and
> @option{-mcpu=powerpc64le} specify pure 32-bit PowerPC (either
