Re: [PATCH 01/11] Add __builtin_speculation_safe_value

["H.J. Lu" <hjl.tools@gmail.com>]

On Mon, Jul 30, 2018 at 6:16 AM, Richard Biener <rguenther@suse.de> wrote:
> On Fri, 27 Jul 2018, Richard Earnshaw wrote:
>
>>
>> This patch defines a new intrinsic function
>> __builtin_speculation_safe_value.  A generic default implementation is
>> defined which will attempt to use the backend pattern
>> "speculation_safe_barrier".  If this pattern is not defined, or if it
>> is not available, then the compiler will emit a warning, but
>> compilation will continue.
>>
>> Note that the test spec-barrier-1.c will currently fail on all
>> targets.  This is deliberate, the failure will go away when
>> appropriate action is taken for each target backend.
>
> OK.
>
> Thanks,
> Richard.
>
>> gcc:
>>       * builtin-types.def (BT_FN_PTR_PTR_VAR): New function type.
>>       (BT_FN_I1_I1_VAR, BT_FN_I2_I2_VAR, BT_FN_I4_I4_VAR): Likewise.
>>       (BT_FN_I8_I8_VAR, BT_FN_I16_I16_VAR): Likewise.
>>       * builtin-attrs.def (ATTR_NOVOPS_NOTHROW_LEAF_LIST): New attribute
>>       list.
>>       * builtins.def (BUILT_IN_SPECULATION_SAFE_VALUE_N): New builtin.
>>       (BUILT_IN_SPECULATION_SAFE_VALUE_PTR): New internal builtin.
>>       (BUILT_IN_SPECULATION_SAFE_VALUE_1): Likewise.
>>       (BUILT_IN_SPECULATION_SAFE_VALUE_2): Likewise.
>>       (BUILT_IN_SPECULATION_SAFE_VALUE_4): Likewise.
>>       (BUILT_IN_SPECULATION_SAFE_VALUE_8): Likewise.
>>       (BUILT_IN_SPECULATION_SAFE_VALUE_16): Likewise.
>>       * builtins.c (expand_speculation_safe_value): New function.
>>       (expand_builtin): Call it.
>>       * doc/cpp.texi: Document predefine __HAVE_SPECULATION_SAFE_VALUE.
>>       * doc/extend.texi: Document __builtin_speculation_safe_value.
>>       * doc/md.texi: Document "speculation_barrier" pattern.
>>       * doc/tm.texi.in: Pull in TARGET_SPECULATION_SAFE_VALUE and
>>       TARGET_HAVE_SPECULATION_SAFE_VALUE.
>>       * doc/tm.texi: Regenerated.
>>       * target.def (have_speculation_safe_value, speculation_safe_value): New
>>       hooks.
>>       * targhooks.c (default_have_speculation_safe_value): New function.
>>       (default_speculation_safe_value): New function.
>>       * targhooks.h (default_have_speculation_safe_value): Add prototype.
>>       (default_speculation_safe_value): Add prototype.
>>

I got

../../src-trunk/gcc/targhooks.c: In function ‘bool
default_have_speculation_safe_value(bool)’:
../../src-trunk/gcc/targhooks.c:2319:43: error: unused parameter
‘active’ [-Werror=unused-parameter]
 default_have_speculation_safe_value (bool active)
                                      ~~~~~^~~~~~

-- 
H.J.