On 5/20/21 10:49 PM, H.J. Lu wrote:
> On Wed, May 19, 2021 at 5:55 AM H.J. Lu <hjl.to...@gmail.com> wrote:
>>
>> On Wed, May 19, 2021 at 2:25 AM Richard Biener
>> <richard.guent...@gmail.com> wrote:
>>>
>>> On Tue, May 18, 2021 at 9:16 PM H.J. Lu <hjl.to...@gmail.com> wrote:
>>>>
>>>> Add TARGET_READ_MEMSET_VALUE and TARGET_GEN_MEMSET_VALUE to support
>>>> target instructions to duplicate QImode value to TImode/OImode/XImode
>>>> value for memmset.
>>>>
>>>> PR middle-end/90773
>>>> * builtins.c (builtin_memset_read_str): Call
>>>> targetm.read_memset_value.
>>>> (builtin_memset_gen_str): Call targetm.gen_memset_value.
>>>> * target.def (read_memset_value): New hook.
>>>> (gen_memset_value): Likewise.
>>>> * targhooks.c: Inclue "builtins.h".
>>>> (default_read_memset_value): New function.
>>>> (default_gen_memset_value): Likewise.
>>>> * targhooks.h (default_read_memset_value): New prototype.
>>>> (default_gen_memset_value): Likewise.
>>>> * doc/tm.texi.in: Add TARGET_READ_MEMSET_VALUE and
>>>> TARGET_GEN_MEMSET_VALUE hooks.
>>>> * doc/tm.texi: Regenerated.
>>>> ---
>>>> gcc/builtins.c | 47 ++++----------------------------------
>>>> gcc/doc/tm.texi | 16 +++++++++++++
>>>> gcc/doc/tm.texi.in | 4 ++++
>>>> gcc/target.def | 20 +++++++++++++++++
>>>> gcc/targhooks.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++
>>>> gcc/targhooks.h | 4 ++++
>>>> 6 files changed, 104 insertions(+), 43 deletions(-)
>>>>
>>>> diff --git a/gcc/builtins.c b/gcc/builtins.c
>>>> index e1b284846b1..f78a36478ef 100644
>>>> --- a/gcc/builtins.c
>>>> +++ b/gcc/builtins.c
>>>> @@ -6584,24 +6584,11 @@ expand_builtin_strncpy (tree exp, rtx target)
>>>> previous iteration. */
>>>>
>>>> rtx
>>>> -builtin_memset_read_str (void *data, void *prevp,
>>>> +builtin_memset_read_str (void *data, void *prev,
>>>> HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
>>>> scalar_int_mode mode)
>>>> {
>>>> - by_pieces_prev *prev = (by_pieces_prev *) prevp;
>>>> - if (prev != nullptr && prev->data != nullptr)
>>>> - {
>>>> - /* Use the previous data in the same mode. */
>>>> - if (prev->mode == mode)
>>>> - return prev->data;
>>>> - }
>>>> -
>>>> - const char *c = (const char *) data;
>>>> - char *p = XALLOCAVEC (char, GET_MODE_SIZE (mode));
>>>> -
>>>> - memset (p, *c, GET_MODE_SIZE (mode));
>>>> -
>>>> - return c_readstr (p, mode);
>>>> + return targetm.read_memset_value ((const char *) data, prev, mode);
>>>> }
>>>>
>>>> /* Callback routine for store_by_pieces. Return the RTL of a register
>>>> @@ -6611,37 +6598,11 @@ builtin_memset_read_str (void *data, void *prevp,
>>>> nullptr, it has the RTL info from the previous iteration. */
>>>>
>>>> static rtx
>>>> -builtin_memset_gen_str (void *data, void *prevp,
>>>> +builtin_memset_gen_str (void *data, void *prev,
>>>> HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
>>>> scalar_int_mode mode)
>>>> {
>>>> - rtx target, coeff;
>>>> - size_t size;
>>>> - char *p;
>>>> -
>>>> - by_pieces_prev *prev = (by_pieces_prev *) prevp;
>>>> - if (prev != nullptr && prev->data != nullptr)
>>>> - {
>>>> - /* Use the previous data in the same mode. */
>>>> - if (prev->mode == mode)
>>>> - return prev->data;
>>>> -
>>>> - target = simplify_gen_subreg (mode, prev->data, prev->mode, 0);
>>>> - if (target != nullptr)
>>>> - return target;
>>>> - }
>>>> -
>>>> - size = GET_MODE_SIZE (mode);
>>>> - if (size == 1)
>>>> - return (rtx) data;
>>>> -
>>>> - p = XALLOCAVEC (char, size);
>>>> - memset (p, 1, size);
>>>> - coeff = c_readstr (p, mode);
>>>> -
>>>> - target = convert_to_mode (mode, (rtx) data, 1);
>>>> - target = expand_mult (mode, target, coeff, NULL_RTX, 1);
>>>> - return force_reg (mode, target);
>>>> + return targetm.gen_memset_value ((rtx) data, prev, mode);
>>>> }
>>>>
>>>> /* Expand expression EXP, which is a call to the memset builtin. Return
>>>> diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
>>>> index 85ea9395560..51385044e76 100644
>>>> --- a/gcc/doc/tm.texi
>>>> +++ b/gcc/doc/tm.texi
>>>> @@ -11868,6 +11868,22 @@ This function prepares to emit a conditional
>>>> comparison within a sequence
>>>> @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the
>>>> compares.
>>>> @end deftypefn
>>>>
>>>> +@deftypefn {Target Hook} rtx TARGET_READ_MEMSET_VALUE (const char
>>>> *@var{c}, void *@var{prev}, scalar_int_mode @var{mode})
>>>> +This function returns the RTL of a constant integer corresponding to
>>>> +target reading @code{GET_MODE_SIZE (@var{mode})} bytes from the stringn
>>>> +constant @var{str}. If @var{prev} is not @samp{nullptr}, it contains
>>>> +the RTL information from the previous interation.
>>>> +@end deftypefn
>>>> +
>>>> +@deftypefn {Target Hook} rtx TARGET_GEN_MEMSET_VALUE (rtx @var{data},
>>>> void *@var{prev}, scalar_int_mode @var{mode})
>>>> +This function returns the RTL of a register containing
>>>> +@code{GET_MODE_SIZE (@var{mode})} consecutive copies of the unsigned
>>>> +char value given in the RTL register @var{data}. For example, if
>>>> +@var{mode} is 4 bytes wide, return the RTL for 0x01010101*@var{data}.
>>>> +If @var{PREV} is not @samp{nullptr}, it is the RTL information from
>>>> +the previous iteration.
>>>> +@end deftypefn
>>>> +
>>>> @deftypefn {Target Hook} unsigned TARGET_LOOP_UNROLL_ADJUST (unsigned
>>>> @var{nunroll}, class loop *@var{loop})
>>>> This target hook returns a new value for the number of times @var{loop}
>>>> should be unrolled. The parameter @var{nunroll} is the number of times
>>>> diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
>>>> index d8e3de14af1..8d4c3949fbf 100644
>>>> --- a/gcc/doc/tm.texi.in
>>>> +++ b/gcc/doc/tm.texi.in
>>>> @@ -7956,6 +7956,10 @@ lists.
>>>>
>>>> @hook TARGET_GEN_CCMP_NEXT
>>>>
>>>> +@hook TARGET_READ_MEMSET_VALUE
>>>> +
>>>> +@hook TARGET_GEN_MEMSET_VALUE
>>>> +
>>>> @hook TARGET_LOOP_UNROLL_ADJUST
>>>>
>>>> @defmac POWI_MAX_MULTS
>>>> diff --git a/gcc/target.def b/gcc/target.def
>>>> index bbaf6b4f3a0..c9aca40fa88 100644
>>>> --- a/gcc/target.def
>>>> +++ b/gcc/target.def
>>>> @@ -2694,6 +2694,26 @@ DEFHOOK
>>>> rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code,
>>>> tree op0, tree op1, int bit_code),
>>>> NULL)
>>>>
>>>> +DEFHOOK
>>>> +(read_memset_value,
>>>> + "This function returns the RTL of a constant integer corresponding to\n\
>>>> +target reading @code{GET_MODE_SIZE (@var{mode})} bytes from the stringn\n\
>>>> +constant @var{str}. If @var{prev} is not @samp{nullptr}, it contains\n\
>>>
>>> where is 'str' defined? I can't really tell what's the difference
>>
>> Fixed with
>>
>> diff --git a/gcc/target.def b/gcc/target.def
>> index c9aca40fa88..4c3a5fcc634 100644
>> --- a/gcc/target.def
>> +++ b/gcc/target.def
>> @@ -2699,8 +2699,8 @@ DEFHOOK
>> "This function returns the RTL of a constant integer corresponding to\n\
>> target reading @code{GET_MODE_SIZE (@var{mode})} bytes from the string\n\
>> constant @var{str}. If @var{prev} is not @samp{nullptr}, it contains\n\
>> -the RTL information from the previous interation.",
>> - rtx, (const char *c, void *prev, scalar_int_mode mode),
>> +the RTL information from the previous iteration.",
>> + rtx, (const char *str, void *prev, scalar_int_mode mode),
>> default_read_memset_value)
>>
>> DEFHOOK
>>
>>> from read_memset_value
>>> and gen_memset_value.
>>
>> The difference is that input of read_memset_value is a string constant
>> like "123" and input of gen_memset_value is an RTL register.
>>
>>> Somehow I feel that an optab for the "splat" operation similar
>>> to vec_duplicate might be a better way to expose this - of course
>>> that doesn't handle the "prev" thing.
>>
>> The x86 backend has ix86_expand_vector_init_duplicate () to
>> broadcast QImode to TImode/OImode/XImode:
>>
>> /* A subroutine of ix86_expand_vector_init. Store into TARGET a vector
>> with all elements equal to VAR. Return true if successful. */
>>
>> bool
>> ix86_expand_vector_init_duplicate (bool mmx_ok, machine_mode mode,
>> rtx target, rtx val)
>>
>>> So how's this the right point of abstraction to the target?
>>
>> I can add 2 target hooks, one for scratch register and one for
>> broadcasting QImode to TImode/OImode/XImode. Then I can
>> move x86 codes to the middle-end.
>>
>
> Here is the patch to add 3 target hooks:
>
> -- Target Hook: rtx TARGET_READ_MEMSET_VALUE (const char *C,
> scalar_int_mode MODE)
> This function returns the RTL of a constant integer corresponding
> to target reading 'GET_MODE_SIZE (MODE)' bytes from the string
> constant C.
>
> -- Target Hook: rtx TARGET_GEN_MEMSET_VALUE (rtx DATA, scalar_int_mode
> MODE)
> This function returns the RTL of a register containing
> 'GET_MODE_SIZE (MODE)' consecutive copies of the unsigned char
> value given in the RTL register DATA. For example, if MODE is 4
> bytes wide, return the RTL for 0x01010101*DATA.
>
> -- Target Hook: rtx TARGET_GEN_MEMSET_VALUE_FROM_PREV (void *PREV,
> scalar_int_mode MODE)
> This function returns the RTL of a register in MODE generated from
> PREV in the previous iteration.
>
> with
>
> /* Return the RTL of a register in MODE generated from PREV in the
> previous iteration. */
>
> static rtx
> gen_memset_value_from_prev (void *prevp, scalar_int_mode mode)
> {
> by_pieces_prev *prev = (by_pieces_prev *) prevp;
> rtx value;
> if (prev != nullptr && prev->data != nullptr)
> {
> /* Use the previous data in the same mode. */
> if (prev->mode == mode)
> return prev->data;
>
> value = targetm.gen_memset_value_from_prev (prevp, mode);
> }
> else
> value = nullptr;
> return value;
> }
>
> /* Callback routine for store_by_pieces. Read GET_MODE_BITSIZE (MODE)
> bytes from constant string DATA + OFFSET and return it as target
> constant. If PREV isn't nullptr, it has the RTL info from the
> previous iteration. */
>
> rtx
> builtin_memset_read_str (void *data, void *prev,
> HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
> scalar_int_mode mode)
> {
> const char *str = (const char *) data;
>
> /* Don't use the previous value if size is 1. */
> if (GET_MODE_SIZE (mode) == 1)
> return default_read_memset_value (str, mode);
>
> rtx value = gen_memset_value_from_prev (prev, mode);
> if (value)
> return value;
>
> return targetm.read_memset_value (str, mode);
> }
>
> /* Callback routine for store_by_pieces. Return the RTL of a register
> containing GET_MODE_SIZE (MODE) consecutive copies of the unsigned
> char value given in the RTL register data. For example, if mode is
> 4 bytes wide, return the RTL for 0x01010101*data. If PREV isn't
> nullptr, it has the RTL info from the previous iteration. */
>
> static rtx
> builtin_memset_gen_str (void *datap, void *prev,
> HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
> scalar_int_mode mode)
> {
> rtx data = (rtx) datap;
>
> /* Don't use the previous value if size is 1. */
> if (GET_MODE_SIZE (mode) == 1)
> return data;
>
> rtx value = gen_memset_value_from_prev (prev, mode);
> if (value)
> return value;
>
> return targetm.gen_memset_value (data, mode);
> }> +/* Default implementation of TARGET_GEN_MEMSET_VALUE. */
> +
> +rtx
> +default_gen_memset_value (rtx data, scalar_int_mode mode)
> +{
> + rtx target, coeff;
> + size_t size;
> + char *p;
> +
> + size = GET_MODE_SIZE (mode);
> + if (size == 1)
> + return data;
> +
> + p = XALLOCAVEC (char, size);
> + memset (p, 1, size);
> + coeff = c_readstr (p, mode);
> +
> + target = convert_to_mode (mode, data, 1);
> + target = expand_mult (mode, target, coeff, NULL_RTX, 1);
Note this formula does not work for data = -1 for instance,
since 0x01010101U * -1 = 0xFEFEFEFFU
but memset(str, n, -1) set it to 0xFFFFFFFFU, right?
So are we sure that the value of "data" is always in the range [0..255] ?
Bernd.
