On Thu, May 20, 2021 at 10:42 PM Bernd Edlinger
<bernd.edlin...@hotmail.de> wrote:
>
> 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] ?
I didn't change the formula. I just turned the current formula into
a target hook. For memset,
DESCRIPTION
The memset() function fills the first n bytes of the memory area
pointed to by s with the constant byte c.
"data", aka the constant byte c, is a byte in the range [0..255].
--
H.J.
