Wilco Dijkstra <wilco.dijks...@arm.com> writes:
> Hi Richard,
>
>> Looks like you might have attached the old patch.  The aarch64_option_restore
>> change is mentioned in the changelog but doesn't appear in the patch itself.
>
> Indeed, not sure how that happened. Here is the correct v2 anyway.
>
> Wilco
>
>
> The --with-cpu/--with-arch configure option processing not only checks valid 
> arguments
> but also sets TARGET_CPU_DEFAULT with a CPU and extension bitmask.  This 
> isn't used
> however since a --with-cpu is translated into a -mcpu option which is 
> processed as if
> written on the command-line (so TARGET_CPU_DEFAULT is never accessed).
>
> So remove all the complex processing and bitmask, and just validate the 
> option.
> Fix a bug that always reports valid architecture extensions as invalid.  As a 
> result
> the CPU processing in aarch64.c can be simplified.
>
> Bootstrap OK, regress pass, OK for commit?
>
> ChangeLog:
> 2022-04-19  Wilco Dijkstra  <wdijk...@arm.com>
>
>         * config.gcc (aarch64*-*-*): Simplify --with-cpu and --with-arch
>         processing.  Add support for architectural extensions.
>         * config/aarch64/aarch64.h (TARGET_CPU_DEFAULT): Remove
>         AARCH64_CPU_DEFAULT_FLAGS.
>         (TARGET_CPU_NBITS): Remove.
>         (TARGET_CPU_MASK): Remove.
>         * config/aarch64/aarch64.cc (AARCH64_CPU_DEFAULT_FLAGS): Remove 
> define.
>         (get_tune_cpu): Assert CPU is always valid.
>         (get_arch): Assert architecture is always valid.
>         (aarch64_override_options): Cleanup CPU selection code and simplify 
> logic.
>         (aarch64_option_restore): Remove unnecessary checks on tune.

OK, thanks.

Richard

> ---
>
> diff --git a/gcc/config.gcc b/gcc/config.gcc
> index 
> c5064dd376660c192d5573997b4fc86b6b3e3838..b48d5451e8027c93fb1f614812589183d0a88c4b
>  100644
> --- a/gcc/config.gcc
> +++ b/gcc/config.gcc
> @@ -4178,8 +4178,6 @@ case "${target}" in
>                           pattern=AARCH64_CORE
>                         fi
>
> -                       ext_mask=AARCH64_CPU_DEFAULT_FLAGS
> -
>                         # Find the base CPU or ARCH id in aarch64-cores.def or
>                         # aarch64-arches.def
>                         if [ x"$base_val" = x ] \
> @@ -4187,23 +4185,6 @@ case "${target}" in
>                                     ${srcdir}/config/aarch64/$def \
>                                     > /dev/null; then
>
> -                         if [ $which = arch ]; then
> -                               base_id=`grep "^$pattern(\"$base_val\"," \
> -                                 ${srcdir}/config/aarch64/$def | \
> -                                 sed -e 's/^[^,]*,[    ]*//' | \
> -                                 sed -e 's/,.*$//'`
> -                               # Extract the architecture flags from 
> aarch64-arches.def
> -                               ext_mask=`grep "^$pattern(\"$base_val\"," \
> -                                  ${srcdir}/config/aarch64/$def | \
> -                                  sed -e 's/)$//' | \
> -                                  sed -e 's/^.*,//'`
> -                         else
> -                               base_id=`grep "^$pattern(\"$base_val\"," \
> -                                 ${srcdir}/config/aarch64/$def | \
> -                                 sed -e 's/^[^,]*,[    ]*//' | \
> -                                 sed -e 's/,.*$//'`
> -                         fi
> -
>                           # Disallow extensions in --with-tune=cortex-a53+crc.
>                           if [ $which = tune ] && [ x"$ext_val" != x ]; then
>                             echo "Architecture extensions not supported in 
> --with-$which=$val" 1>&2
> @@ -4234,25 +4215,7 @@ case "${target}" in
>                                         grep "^\"$base_ext\""`
>
>                                 if [ x"$base_ext" = x ] \
> -                                   || [[ -n $opt_line ]]; then
> -
> -                                 # These regexp extract the elements based on
> -                                 # their group match index in the regexp.
> -                                 ext_canon=`echo -e "$opt_line" | \
> -                                       sed -e "s/$sed_patt/\2/"`
> -                                 ext_on=`echo -e "$opt_line" | \
> -                                       sed -e "s/$sed_patt/\3/"`
> -                                 ext_off=`echo -e "$opt_line" | \
> -                                       sed -e "s/$sed_patt/\4/"`
> -
> -                                 if [ $ext = $base_ext ]; then
> -                                       # Adding extension
> -                                       ext_mask="("$ext_mask") | ("$ext_on" 
> | "$ext_canon")"
> -                                 else
> -                                       # Removing extension
> -                                       ext_mask="("$ext_mask") & 
> ~("$ext_off" | "$ext_canon")"
> -                                 fi
> -
> +                                   || [ x"$opt_line" != x ]; then
>                                   true
>                                 else
>                                   echo "Unknown extension used in 
> --with-$which=$val" 1>&2
> @@ -4261,10 +4224,6 @@ case "${target}" in
>                                 ext_val=`echo $ext_val | sed -e 
> 's/[a-z0-9]\+//'`
>                           done
>
> -                         ext_mask="(("$ext_mask") << TARGET_CPU_NBITS)"
> -                         if [ x"$base_id" != x ]; then
> -                               target_cpu_cname="TARGET_CPU_$base_id | 
> $ext_mask"
> -                         fi
>                           true
>                         else
>                           # Allow --with-$which=native.
> diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
> index 
> 359b6e8561faa38f53a806b8c114c83ae37e7e17..f835da33b72f36bbf25a0e1328135411bd8ab4f6
>  100644
> --- a/gcc/config/aarch64/aarch64.h
> +++ b/gcc/config/aarch64/aarch64.h
> @@ -813,16 +813,9 @@ enum target_cpus
>    TARGET_CPU_generic
>  };
>
> -/* Define how many bits are used to represent the CPU in TARGET_CPU_DEFAULT.
> -   This needs to be big enough to fit the value of TARGET_CPU_generic.
> -   All bits after this are used to represent the AARCH64_CPU_DEFAULT_FLAGS.  
> */
> -#define TARGET_CPU_NBITS 8
> -#define TARGET_CPU_MASK ((1 << TARGET_CPU_NBITS) - 1)
> -
>  /* If there is no CPU defined at configure, use generic as default.  */
>  #ifndef TARGET_CPU_DEFAULT
> -#define TARGET_CPU_DEFAULT \
> -  (TARGET_CPU_generic | (AARCH64_CPU_DEFAULT_FLAGS << TARGET_CPU_NBITS))
> +# define TARGET_CPU_DEFAULT TARGET_CPU_generic
>  #endif
>
>  /* If inserting NOP before a mult-accumulate insn remember to adjust the
> diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
> index 
> 1ec15741a4dba055b02732985d5a92a9252b166b..9294de799461f7f94c563f56b02e6e485ab7f1e6
>  100644
> --- a/gcc/config/aarch64/aarch64.cc
> +++ b/gcc/config/aarch64/aarch64.cc
> @@ -2760,8 +2760,6 @@ static const struct attribute_spec 
> aarch64_attribute_table[] =
>    { NULL,                 0, 0, false, false, false, false, NULL, NULL }
>  };
>
> -#define AARCH64_CPU_DEFAULT_FLAGS ((selected_cpu) ? selected_cpu->flags : 0)
> -
>  /* An ISA extension in the co-processor and main instruction set space.  */
>  struct aarch64_option_extension
>  {
> @@ -18040,39 +18038,24 @@ aarch64_validate_mtune (const char *str, const 
> struct processor **res)
>    return false;
>  }
>
> -static_assert (TARGET_CPU_generic < TARGET_CPU_MASK,
> -              "TARGET_CPU_NBITS is big enough");
> -
> -/* Return the CPU corresponding to the enum CPU.
> -   If it doesn't specify a cpu, return the default.  */
> +/* Return the CPU corresponding to the enum CPU.  */
>
>  static const struct processor *
>  aarch64_get_tune_cpu (enum aarch64_processor cpu)
>  {
> -  if (cpu != aarch64_none)
> -    return &all_cores[cpu];
> +  gcc_assert (cpu != aarch64_none);
>
> -  /* The & TARGET_CPU_MASK is to extract the bottom TARGET_CPU_NBITS bits 
> that
> -     encode the default cpu as selected by the --with-cpu GCC configure 
> option
> -     in config.gcc.
> -     ???: The whole TARGET_CPU_DEFAULT and AARCH64_CPU_DEFAULT_FLAGS
> -     flags mechanism should be reworked to make it more sane.  */
> -  return &all_cores[TARGET_CPU_DEFAULT & TARGET_CPU_MASK];
> +  return &all_cores[cpu];
>  }
>
> -/* Return the architecture corresponding to the enum ARCH.
> -   If it doesn't specify a valid architecture, return the default.  */
> +/* Return the architecture corresponding to the enum ARCH.  */
>
>  static const struct processor *
>  aarch64_get_arch (enum aarch64_arch arch)
>  {
> -  if (arch != aarch64_no_arch)
> -    return &all_architectures[arch];
> -
> -  const struct processor *cpu
> -    = &all_cores[TARGET_CPU_DEFAULT & TARGET_CPU_MASK];
> +  gcc_assert (arch != aarch64_no_arch);
>
> -  return &all_architectures[cpu->arch];
> +  return &all_architectures[arch];
>  }
>
>  /* Return the VG value associated with -msve-vector-bits= value VALUE.  */
> @@ -18110,10 +18093,6 @@ aarch64_override_options (void)
>    uint64_t arch_isa = 0;
>    aarch64_isa_flags = 0;
>
> -  bool valid_cpu = true;
> -  bool valid_tune = true;
> -  bool valid_arch = true;
> -
>    selected_cpu = NULL;
>    selected_arch = NULL;
>    selected_tune = NULL;
> @@ -18128,77 +18107,56 @@ aarch64_override_options (void)
>       If either of -march or -mtune is given, they override their
>       respective component of -mcpu.  */
>    if (aarch64_cpu_string)
> -    valid_cpu = aarch64_validate_mcpu (aarch64_cpu_string, &selected_cpu,
> -                                       &cpu_isa);
> +    aarch64_validate_mcpu (aarch64_cpu_string, &selected_cpu, &cpu_isa);
>
>    if (aarch64_arch_string)
> -    valid_arch = aarch64_validate_march (aarch64_arch_string, &selected_arch,
> -                                         &arch_isa);
> +    aarch64_validate_march (aarch64_arch_string, &selected_arch, &arch_isa);
>
>    if (aarch64_tune_string)
> -    valid_tune = aarch64_validate_mtune (aarch64_tune_string, 
> &selected_tune);
> +    aarch64_validate_mtune (aarch64_tune_string, &selected_tune);
>
>  #ifdef SUBTARGET_OVERRIDE_OPTIONS
>    SUBTARGET_OVERRIDE_OPTIONS;
>  #endif
>
> -  /* If the user did not specify a processor, choose the default
> -     one for them.  This will be the CPU set during configuration using
> -     --with-cpu, otherwise it is "generic".  */
> -  if (!selected_cpu)
> -    {
> -      if (selected_arch)
> -       {
> -         selected_cpu = &all_cores[selected_arch->ident];
> -         aarch64_isa_flags = arch_isa;
> -         explicit_arch = selected_arch->arch;
> -       }
> -      else
> -       {
> -         /* Get default configure-time CPU.  */
> -         selected_cpu = aarch64_get_tune_cpu (aarch64_none);
> -         aarch64_isa_flags = TARGET_CPU_DEFAULT >> TARGET_CPU_NBITS;
> -       }
> -
> -      if (selected_tune)
> -       explicit_tune_core = selected_tune->ident;
> -    }
> -  /* If both -mcpu and -march are specified check that they are 
> architecturally
> -     compatible, warn if they're not and prefer the -march ISA flags.  */
> -  else if (selected_arch)
> +  if (selected_cpu && selected_arch)
>      {
> +      /* If both -mcpu and -march are specified, warn if they are not
> +        architecturally compatible and prefer the -march ISA flags.  */
>        if (selected_arch->arch != selected_cpu->arch)
>         {
>           warning (0, "switch %<-mcpu=%s%> conflicts with %<-march=%s%> 
> switch",
>                        aarch64_cpu_string,
>                        aarch64_arch_string);
>         }
> +
>        aarch64_isa_flags = arch_isa;
> -      explicit_arch = selected_arch->arch;
> -      explicit_tune_core = selected_tune ? selected_tune->ident
> -                                         : selected_cpu->ident;
>      }
> -  else
> +  else if (selected_cpu)
>      {
> -      /* -mcpu but no -march.  */
> -      aarch64_isa_flags = cpu_isa;
> -      explicit_tune_core = selected_tune ? selected_tune->ident
> -                                         : selected_cpu->ident;
> -      gcc_assert (selected_cpu);
>        selected_arch = &all_architectures[selected_cpu->arch];
> -      explicit_arch = selected_arch->arch;
> +      aarch64_isa_flags = cpu_isa;
>      }
> -
> -  /* Set the arch as well as we will need it when outputing
> -     the .arch directive in assembly.  */
> -  if (!selected_arch)
> +  else if (selected_arch)
>      {
> -      gcc_assert (selected_cpu);
> +      selected_cpu = &all_cores[selected_arch->ident];
> +      aarch64_isa_flags = arch_isa;
> +    }
> +  else
> +    {
> +      /* No -mcpu or -march specified, so use the default CPU.  */
> +      selected_cpu = &all_cores[TARGET_CPU_DEFAULT];
>        selected_arch = &all_architectures[selected_cpu->arch];
> +      aarch64_isa_flags = selected_cpu->flags;
>      }
>
> +  explicit_arch = selected_arch->arch;
>    if (!selected_tune)
>      selected_tune = selected_cpu;
> +  explicit_tune_core = selected_tune->ident;
> +
> +  gcc_assert (explicit_tune_core != aarch64_none);
> +  gcc_assert (explicit_arch != aarch64_no_arch);
>
>    if (aarch64_enable_bti == 2)
>      {
> @@ -18234,15 +18192,6 @@ aarch64_override_options (void)
>    if (aarch64_ra_sign_scope != AARCH64_FUNCTION_NONE && TARGET_ILP32)
>      sorry ("return address signing is only supported for %<-mabi=lp64%>");
>
> -  /* Make sure we properly set up the explicit options.  */
> -  if ((aarch64_cpu_string && valid_cpu)
> -       || (aarch64_tune_string && valid_tune))
> -    gcc_assert (explicit_tune_core != aarch64_none);
> -
> -  if ((aarch64_cpu_string && valid_cpu)
> -       || (aarch64_arch_string && valid_arch))
> -    gcc_assert (explicit_arch != aarch64_no_arch);
> -
>    /* The pass to insert speculation tracking runs before
>       shrink-wrapping and the latter does not know how to update the
>       tracking status.  So disable it in this case.  */
> @@ -18348,11 +18297,7 @@ aarch64_option_restore (struct gcc_options *opts,
>    opts->x_explicit_arch = ptr->x_explicit_arch;
>    selected_arch = aarch64_get_arch (ptr->x_explicit_arch);
>    opts->x_explicit_tune_core = ptr->x_explicit_tune_core;
> -  if (opts->x_explicit_tune_core == aarch64_none
> -      && opts->x_explicit_arch != aarch64_no_arch)
> -    selected_tune = &all_cores[selected_arch->ident];
> -  else
> -    selected_tune = aarch64_get_tune_cpu (ptr->x_explicit_tune_core);
> +  selected_tune = aarch64_get_tune_cpu (ptr->x_explicit_tune_core);
>    opts->x_aarch64_override_tune_string = ptr->x_aarch64_override_tune_string;
>    opts->x_aarch64_branch_protection_string
>      = ptr->x_aarch64_branch_protection_string;

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