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.
> > +the RTL information from the previous interation.",
> > + rtx, (const char *c, void *prev, scalar_int_mode mode),
> > + default_read_memset_value)
> > +
> > +DEFHOOK
> > +(gen_memset_value,
> > + "This function returns the RTL of a register containing\n\
> > +@code{GET_MODE_SIZE (@var{mode})} consecutive copies of the unsigned\n\
> > +char value given in the RTL register @var{data}. For example, if\n\
> > +@var{mode} is 4 bytes wide, return the RTL for 0x01010101*@var{data}.\n\
> > +If @var{PREV} is not @samp{nullptr}, it is the RTL information from\n\
> > +the previous iteration.",
> > + rtx, (rtx data, void *prev, scalar_int_mode mode),
> > + default_gen_memset_value)
> > +
> > /* Return a new value for loop unroll size. */
> > DEFHOOK
> > (loop_unroll_adjust,
> > diff --git a/gcc/targhooks.c b/gcc/targhooks.c
> > index 1947ef26fd6..b55e6ec6756 100644
> > --- a/gcc/targhooks.c
> > +++ b/gcc/targhooks.c
> > @@ -90,6 +90,7 @@ along with GCC; see the file COPYING3. If not see
> > #include "attribs.h"
> > #include "asan.h"
> > #include "emit-rtl.h"
> > +#include "builtins.h"
> >
> > bool
> > default_legitimate_address_p (machine_mode mode ATTRIBUTE_UNUSED,
> > @@ -2627,4 +2628,59 @@ default_memtag_untagged_pointer (rtx tagged_pointer,
> > rtx target)
> > return untagged_base;
> > }
> >
> > +/* Default implementation of TARGET_READ_MEMSET_VALUE. */
> > +
> > +rtx
> > +default_read_memset_value (const char *c, void *prevp,
> > + 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;
> > + }
> > +
> > + char *p = XALLOCAVEC (char, GET_MODE_SIZE (mode));
> > +
> > + memset (p, *c, GET_MODE_SIZE (mode));
> > +
> > + return c_readstr (p, mode);
> > +}
> > +
> > +/* Default implementation of TARGET_GEN_MEMSET_VALUE. */
> > +
> > +rtx
> > +default_gen_memset_value (rtx data, void *prevp, 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 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);
> > + return force_reg (mode, target);
> > +}
> > +
> > #include "gt-targhooks.h"
> > diff --git a/gcc/targhooks.h b/gcc/targhooks.h
> > index b537038c0aa..3c00927e196 100644
> > --- a/gcc/targhooks.h
> > +++ b/gcc/targhooks.h
> > @@ -300,4 +300,8 @@ extern rtx default_memtag_set_tag (rtx, rtx, rtx);
> > extern rtx default_memtag_extract_tag (rtx, rtx);
> > extern rtx default_memtag_untagged_pointer (rtx, rtx);
> >
> > +extern rtx default_read_memset_value (const char *, void *,
> > + scalar_int_mode);
> > +extern rtx default_gen_memset_value (rtx, void *, scalar_int_mode);
> > +
> > #endif /* GCC_TARGHOOKS_H */
> > --
> > 2.31.1
> >
--
H.J.
