On Mon, 2020-04-06 at 12:52 -0400, Michael Meissner via Gcc-patches wrote:
Hi,
Just a single extra blank line below.
I'm still not a fan of the "Do not set..." comment, but will assume there
is history that necessitates the comment.
Other sections looked OK to me.
Over to Segher. :-)
Thanks,
-Will
> Commit message:
> Enable -mpcrel for -mcpu=future if it is allowed by the ABI.
>
> 2020-04-06 Michael Meissner <meiss...@linux.ibm.com>
>
> * config/rs6000/linux64.h (PCREL_SUPPORTED_BY_OS): Enable
> prefixed PC-relative addressing if the ABI supports it.
> * config/rs6000/rs6000-cpus.def (ISA_FUTURE_MASKS_SERVER): Do not
> set OPTION_MASK_PREFIXED here.
> * config/rs6000/rs6000.c (rs6000_option_override_internal): Enable
> OPTION_MASK_PREFIXED and OPTION_MASK_PCREL on -mcpu=future by
> default if the current ABI allows the options.
>
> I tested this on a little endian PowerPC power8 system, doing bootstrap and
> make check. There were no regressions. I tested by hand the various
> conditions where -mpcrel is not enabled, and they all used the normal power9
> TOC references.
>
> -mcpu=power9 generates TOC;
> -mcpu=future -mcmodel=large generates TOC;
> -mcpu=future -mcmode=small generates TOC;
> -mcpu=future -mno-prefixed generates TOC;
> -mcpu=future -mno-pcrel generates TOC;
> -mcpu=future generates PC-relative.
>
ok,
> --- /tmp/apbaWN_linux64.h 2020-04-03 17:15:05.059677000 -0400
> +++ gcc/config/rs6000/linux64.h 2020-04-03 17:01:05.580426937 -0400
> @@ -640,3 +640,10 @@ extern int dot_symbols;
> enabling the __float128 keyword. */
> #undef TARGET_FLOAT128_ENABLE_TYPE
> #define TARGET_FLOAT128_ENABLE_TYPE 1
> +
> +/* Enable using prefixed PC-relative addressing on the 'future' machine if
> the
> + ABI supports it. The ELF v2 ABI only supports PC-relative relocations for
> + the medium code model. */
> +#define PCREL_SUPPORTED_BY_OS (TARGET_FUTURE && TARGET_PREFIXED
> \
> + && ELFv2_ABI_CHECK \
> + && (TARGET_CMODEL == CMODEL_MEDIUM))
ok
> --- /tmp/XzRKno_rs6000-cpus.def 2020-04-03 17:15:05.068676928 -0400
> +++ gcc/config/rs6000/rs6000-cpus.def 2020-04-03 17:00:50.115550614 -0400
> @@ -75,10 +75,14 @@
> | OPTION_MASK_P8_VECTOR \
> | OPTION_MASK_P9_VECTOR)
>
> -/* Support for a future processor's features. Do not enable -mpcrel until it
> - is fully functional. */
> +/* Support for a future processor's features. Do not set
> OPTION_MASK_PREFIXED
> + or OPTION_MASK_PCREL here. Those options are enabled in the function
> + rs6000_option_override if the ABI supports them. */
> #define ISA_FUTURE_MASKS_SERVER (ISA_3_0_MASKS_SERVER
> \
> - | OPTION_MASK_FUTURE \
> + | OPTION_MASK_FUTURE)
> +
> +/* Flags that need to be turned off if -mno-future. */
> +#define OTHER_FUTURE_MASKS (OPTION_MASK_PCREL \
> | OPTION_MASK_PREFIXED)
>
ok.
> /* Flags that need to be turned off if -mno-future. */
> --- /tmp/nyxSRY_rs6000.c 2020-04-03 17:15:05.081676823 -0400
> +++ gcc/config/rs6000/rs6000.c 2020-04-03 17:03:19.846353197 -0400
> @@ -4020,6 +4020,12 @@ rs6000_option_override_internal (bool gl
> rs6000_isa_flags &= ~OPTION_MASK_FLOAT128_HW;
> }
>
> + /* Enable -mprefixed by default on 64-bit 'future' systems. */
> + if (TARGET_FUTURE && TARGET_POWERPC64
> + && (rs6000_isa_flags_explicit & OPTION_MASK_PREFIXED) == 0)
> + rs6000_isa_flags |= OPTION_MASK_PREFIXED;
> +
> +
extra blank line.
> /* -mprefixed (and hence -mpcrel) requires -mcpu=future. */
> if (TARGET_PREFIXED && !TARGET_FUTURE)
> {
> @@ -4171,6 +4177,14 @@ rs6000_option_override_internal (bool gl
> SUB3TARGET_OVERRIDE_OPTIONS;
> #endif
>
> +#ifdef PCREL_SUPPORTED_BY_OS
> + /* If the ABI has support for PC-relative relocations, enable it by
> + default. */
> + if (PCREL_SUPPORTED_BY_OS
> + && (rs6000_isa_flags_explicit & OPTION_MASK_PCREL) == 0)
> + rs6000_isa_flags |= OPTION_MASK_PCREL;
> +#endif
> +
ok.
> /* -mpcrel requires -mcmodel=medium, but we can't check TARGET_CMODEL until
> after the subtarget override options are done. */
> if (TARGET_PCREL && TARGET_CMODEL != CMODEL_MEDIUM)
>
