On Tue, 2021-05-18 at 16:36 -0400, Michael Meissner wrote:
> [PATCH] Allow __ibm128 on older PowerPC systems.
>
Hi,
> On January 8th, 2018, I added code to ibm-ldouble.c to use the built-in
> function __builtin_pack_ibm128 if long double is IEEE 128-bit and continue to
> use __builtin_pack_longdouble if long double is IBM extended double. This
> code
> was needed because __builtin_pack_ibm128 is not available unless the __ibm128
> keyword is availabe. In the current code, __ibm128 is only enabled if we have
> support for both IBM and IEEE 128-bit long double.
"available."
May be worth re-sifting the description to drop the history not
directly applicable to what this patch is doing.
>
> Segher suggested that instead I should make __ibm128, __builtin_pack_ibm128,
> and __builtin_unpack_ibm128 available on older systems that don't support IEEE
> 128-bit floating point but does support the IBM extended double floating
> point.
>
> This patch changes the code so that __ibm128 is now exported if either
> long double uses the IBM extended double format, or IEEE 128-bit floating
> point is available.
>
> I changed the internal built-in types from float128 to ibm128, since the
> only built-in functions that use this are __builtin_pack_ibm128 and
> __builtin_unpack_ibm128, and the new name matches the function.
>
> In addition, this patch changes the function within libgcc that handles
> IBM long double to use the __builtin_pack_ibm128 function.
ok
>
> I have done bootstrap builds with this patch on the following 3 systems:
> 1) power9 running LE Linux using --with-cpu=power9
> 2) power8 running BE Linux using --with-cpu=power8, testing both
> 32/64-bit.
> 3) power10 prototype running LE Linux using --with-cpu=power10.
>
> There were no regressions to the tests, and the new test added passed. Can I
> check these patches into trunk branch for GCC 12?
>
> At the moment, I'm not sure this should be backported to GCC 11. But I can
> easily do the back port after a stabilizing period.
>
> gcc/
> 2021-05-18 Michael Meissner <meiss...@linux.ibm.com>
>
> * config/rs6000/rs6000-builtin.def (BU_IBM128_2): Rename
> RS6000_BTM_IBM128 from RS6000_BTM_FLOAT128.
> * config/rs6000/rs6000-call.c (rs6000_invalid_builtin): Update
> error message for __ibm128 built-in functions.
> (rs6000_init_builtins): Create the __ibm128 keyword on older
> systems where long double uses the IBM extended double format,
> even if they don't support IEEE 128-bit floating point.
Could drop 'older', ok.
> * config/rs6000/rs6000.c (rs6000_builtin_mask_calculate): Rename
> RS6000_BTM_IBM128 from RS6000_BTM_FLOAT128.
> (rs6000_builtin_mask_names): Rename RS6000_BTM_IBM128 from
> RS6000_BTM_FLOAT128.
> * config/rs6000/rs6000.h (TARGET_IBM128): New macro.
> (RS6000_BTM_IBM128): Rename from RS6000_BTM_FLOAT128.
> (RS6000_BTM_COMMON): Rename RS6000_BTM_IBM128 from
> RS6000_BTM_FLOAT128.
ok
>
> libgcc/
> 2021-05-18 Michael Meissner <meiss...@linux.ibm.com>
>
> * config/rs6000/ibm-ldouble.c (pack_ldouble): Use
> __builtin_pack_ibm128 instead of __builtin_pack_longdouble.
> ---
> gcc/config/rs6000/rs6000-builtin.def | 5 ++---
> gcc/config/rs6000/rs6000-call.c | 14 ++++++++++----
> gcc/config/rs6000/rs6000.c | 4 ++--
> gcc/config/rs6000/rs6000.h | 12 +++++++++---
> libgcc/config/rs6000/ibm-ldouble.c | 4 ++--
> 5 files changed, 25 insertions(+), 14 deletions(-)
>
> diff --git a/gcc/config/rs6000/rs6000-builtin.def
> b/gcc/config/rs6000/rs6000-builtin.def
> index 609bebdfd74..6d82ed224fb 100644
> --- a/gcc/config/rs6000/rs6000-builtin.def
> +++ b/gcc/config/rs6000/rs6000-builtin.def
> @@ -796,13 +796,12 @@
> | RS6000_BTC_BINARY), \
> CODE_FOR_ ## ICODE) /* ICODE */
>
> -/* 128-bit __ibm128 floating point builtins (use -mfloat128 to indicate that
> - __ibm128 is available). */
> +/* 128-bit __ibm128 floating point builtins. */
> #define BU_IBM128_2(ENUM, NAME, ATTR, ICODE) \
> RS6000_BUILTIN_2 (MISC_BUILTIN_ ## ENUM, /* ENUM */ \
> "__builtin_" NAME, /* NAME */ \
> (RS6000_BTM_HARD_FLOAT /* MASK */ \
> - | RS6000_BTM_FLOAT128), \
> + | RS6000_BTM_IBM128), \
> (RS6000_BTC_ ## ATTR /* ATTR */ \
> | RS6000_BTC_BINARY), \
> CODE_FOR_ ## ICODE) /* ICODE */
ok
> diff --git a/gcc/config/rs6000/rs6000-call.c b/gcc/config/rs6000/rs6000-call.c
> index c4332a61862..7bdc4eeca5f 100644
> --- a/gcc/config/rs6000/rs6000-call.c
> +++ b/gcc/config/rs6000/rs6000-call.c
> @@ -11540,8 +11540,8 @@ rs6000_invalid_builtin (enum rs6000_builtins fncode)
> error ("%qs requires the %qs option", name, "-mhard-float");
> else if ((fnmask & RS6000_BTM_FLOAT128_HW) != 0)
> error ("%qs requires ISA 3.0 IEEE 128-bit floating point", name);
> - else if ((fnmask & RS6000_BTM_FLOAT128) != 0)
> - error ("%qs requires the %qs option", name, "%<-mfloat128%>");
> + else if ((fnmask & RS6000_BTM_IBM128) != 0)
> + error ("%qs requires the IBM 128-bit floating point", name);
> else if ((fnmask & (RS6000_BTM_POPCNTD | RS6000_BTM_POWERPC64))
> == (RS6000_BTM_POPCNTD | RS6000_BTM_POWERPC64))
> error ("%qs requires the %qs (or newer), and %qs or %qs options",
> @@ -13236,7 +13236,7 @@ rs6000_init_builtins (void)
> For IEEE 128-bit floating point, always create the type __ieee128. If
> the
> user used -mfloat128, rs6000-c.c will create a define from __float128 to
> __ieee128. */
> - if (TARGET_FLOAT128_TYPE)
> + if (TARGET_IBM128)
> {
> if (!TARGET_IEEEQUAD && TARGET_LONG_DOUBLE_128)
> ibm128_float_type_node = long_double_type_node;
> @@ -13250,7 +13250,13 @@ rs6000_init_builtins (void)
>
> lang_hooks.types.register_builtin_type (ibm128_float_type_node,
> "__ibm128");
> + }
> +
> + else
> + ibm128_float_type_node = long_double_type_node;
>
> + if (TARGET_FLOAT128_TYPE)
> + {
> if (TARGET_IEEEQUAD && TARGET_LONG_DOUBLE_128)
> ieee128_float_type_node = long_double_type_node;
> else
> @@ -13261,7 +13267,7 @@ rs6000_init_builtins (void)
> }
>
> else
> - ieee128_float_type_node = ibm128_float_type_node = long_double_type_node;
> + ieee128_float_type_node = long_double_type_node;
>
> /* Vector pair and vector quad support. */
> if (TARGET_EXTRA_BUILTINS)
ok
> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> index 44ae3adbe7a..86f53297cb9 100644
> --- a/gcc/config/rs6000/rs6000.c
> +++ b/gcc/config/rs6000/rs6000.c
> @@ -3427,7 +3427,7 @@ rs6000_builtin_mask_calculate (void)
> | ((TARGET_LONG_DOUBLE_128
> && TARGET_HARD_FLOAT
> && !TARGET_IEEEQUAD) ? RS6000_BTM_LDBL128 : 0)
> - | ((TARGET_FLOAT128_TYPE) ? RS6000_BTM_FLOAT128 : 0)
> + | ((TARGET_IBM128) ? RS6000_BTM_IBM128 : 0)
> | ((TARGET_FLOAT128_HW) ? RS6000_BTM_FLOAT128_HW : 0)
> | ((TARGET_MMA) ? RS6000_BTM_MMA : 0)
> | ((TARGET_POWER10) ? RS6000_BTM_P10 : 0));
> @@ -24164,7 +24164,7 @@ static struct rs6000_opt_mask const
> rs6000_builtin_mask_names[] =
> { "hard-float", RS6000_BTM_HARD_FLOAT, false, false },
> { "long-double-128", RS6000_BTM_LDBL128, false, false },
> { "powerpc64", RS6000_BTM_POWERPC64, false, false },
> - { "float128", RS6000_BTM_FLOAT128, false, false },
> + { "ibm128", RS6000_BTM_IBM128, false, false },
> { "float128-hw", RS6000_BTM_FLOAT128_HW,false, false },
> { "mma", RS6000_BTM_MMA, false, false },
> { "power10", RS6000_BTM_P10, false, false },
ok
> diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
> index 164d359b724..b0e1953aeae 100644
> --- a/gcc/config/rs6000/rs6000.h
> +++ b/gcc/config/rs6000/rs6000.h
> @@ -504,6 +504,12 @@ extern int rs6000_vector_align[];
> #define TARGET_MINMAX (TARGET_HARD_FLOAT && TARGET_PPC_GFXOPT
> \
> && (TARGET_P9_MINMAX || !flag_trapping_math))
>
> +/* Whether the '__ibm128' keywork is enabled. We enable __ibm128 either if
> the
'Whether...' reads a bit strange, but it looks mostly consistent with
other comments in rs6000.h.
> + IEEE 128-bit floating point support is enabled or if the long double
> support
> + uses the 128-bit IBM extended double format. */
> +#define TARGET_IBM128 (TARGET_FLOAT128_TYPE
> \
> + || (!TARGET_IEEEQUAD && TARGET_LONG_DOUBLE_128))
> +
> /* In switching from using target_flags to using rs6000_isa_flags, the
> options
> machinery creates OPTION_MASK_<xxx> instead of MASK_<xxx>. For now map
> OPTION_MASK_<xxx> back into MASK_<xxx>. */
> @@ -2305,7 +2311,7 @@ extern int frame_pointer_needed;
> #define RS6000_BTC_SAT RS6000_BTC_MISC /* saturate sets VSCR.
> */
>
> /* Builtin targets. For now, we reuse the masks for those options that are
> in
> - target flags, and pick a random bit for ldbl128, which isn't in
> + target flags, and pick a random bit for ldbl128 and ibm128, which aren't
> in
> target_flags. */
> #define RS6000_BTM_ALWAYS 0 /* Always enabled. */
> #define RS6000_BTM_ALTIVEC MASK_ALTIVEC /* VMX/altivec vectors. */
> @@ -2327,7 +2333,7 @@ extern int frame_pointer_needed;
> #define RS6000_BTM_LDBL128 MASK_MULTIPLE /* 128-bit long double. */
> #define RS6000_BTM_64BIT MASK_64BIT /* 64-bit addressing. */
> #define RS6000_BTM_POWERPC64 MASK_POWERPC64 /* 64-bit registers. */
> -#define RS6000_BTM_FLOAT128 MASK_FLOAT128_KEYWORD /* IEEE 128-bit float. */
> +#define RS6000_BTM_IBM128 MASK_FLOAT128_KEYWORD /* __ibm128 keyword. */
> #define RS6000_BTM_FLOAT128_HW MASK_FLOAT128_HW /* IEEE 128-bit float
> h/w. */
> #define RS6000_BTM_MMA MASK_MMA /* ISA 3.1 MMA. */
> #define RS6000_BTM_P10 MASK_POWER10
> @@ -2351,7 +2357,7 @@ extern int frame_pointer_needed;
> | RS6000_BTM_HARD_FLOAT \
> | RS6000_BTM_LDBL128 \
> | RS6000_BTM_POWERPC64 \
> - | RS6000_BTM_FLOAT128 \
> + | RS6000_BTM_IBM128 \
> | RS6000_BTM_FLOAT128_HW \
> | RS6000_BTM_MMA \
> | RS6000_BTM_P10)
ok
> diff --git a/libgcc/config/rs6000/ibm-ldouble.c
> b/libgcc/config/rs6000/ibm-ldouble.c
> index 4c13453f975..92b4b4c583d 100644
> --- a/libgcc/config/rs6000/ibm-ldouble.c
> +++ b/libgcc/config/rs6000/ibm-ldouble.c
> @@ -102,9 +102,9 @@ __asm__ (".symver __gcc_qadd,_xlqadd@GCC_3.4\n\t"
> static inline IBM128_TYPE
> pack_ldouble (double dh, double dl)
> {
> -#if defined (__LONG_DOUBLE_128__) && defined (__LONG_DOUBLE_IBM128__)
> \
> +#if defined (__LONG_DOUBLE_128__) \
> && !(defined (_SOFT_FLOAT) || defined (__NO_FPRS__))
> - return __builtin_pack_longdouble (dh, dl);
> + return __builtin_pack_ibm128 (dh, dl);
> #else
> union
> {
ok
Thanks,
-Will
> --
> 2.31.1
>
