"H.J. Lu via Gcc-patches" <gcc-patches@gcc.gnu.org> writes:
> On Fri, Jul 16, 2021 at 7:15 AM H.J. Lu <hjl.to...@gmail.com> wrote:
>>
>> On Fri, Jul 16, 2021 at 6:24 AM Richard Sandiford
>> <richard.sandif...@arm.com> wrote:
>> >
>> > "H.J. Lu via Gcc-patches" <gcc-patches@gcc.gnu.org> writes:
>> > > On Fri, Jul 16, 2021 at 4:38 AM Richard Sandiford
>> > > <richard.sandif...@arm.com> wrote:
>> > >>
>> > >> "H.J. Lu via Gcc-patches" <gcc-patches@gcc.gnu.org> writes:
>> > >> > 1. Rewrite builtin_memset_read_str and builtin_memset_gen_str with
>> > >> > vec_duplicate_optab to duplicate QI value to TI/OI/XI value.
>> > >> > 2. Add TARGET_GEN_MEMSET_SCRATCH_RTX to allow the backend to use a
>> > >> > hard
>> > >> > scratch register to avoid stack realignment when expanding memset.
>> > >> >
>> > >> > PR middle-end/90773
>> > >> > * builtins.c (gen_memset_value_from_prev): New function.
>> > >> > (gen_memset_broadcast): Likewise.
>> > >> > (builtin_memset_read_str): Use gen_memset_value_from_prev
>> > >> > and gen_memset_broadcast.
>> > >> > (builtin_memset_gen_str): Likewise.
>> > >> > * target.def (gen_memset_scratch_rtx): New hook.
>> > >> > * doc/tm.texi.in: Add TARGET_GEN_MEMSET_SCRATCH_RTX.
>> > >> > * doc/tm.texi: Regenerated.
>> > >> > ---
>> > >> > gcc/builtins.c | 123
>> > >> > +++++++++++++++++++++++++++++++++++++--------
>> > >> > gcc/doc/tm.texi | 5 ++
>> > >> > gcc/doc/tm.texi.in | 2 +
>> > >> > gcc/target.def | 7 +++
>> > >> > 4 files changed, 116 insertions(+), 21 deletions(-)
>> > >> >
>> > >> > diff --git a/gcc/builtins.c b/gcc/builtins.c
>> > >> > index 39ab139b7e1..c1758ae2efc 100644
>> > >> > --- a/gcc/builtins.c
>> > >> > +++ b/gcc/builtins.c
>> > >> > @@ -6686,26 +6686,111 @@ expand_builtin_strncpy (tree exp, rtx target)
>> > >> > return NULL_RTX;
>> > >> > }
>> > >> >
>> > >> > -/* 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
>> > >> > +/* Return the RTL of a register in MODE generated from PREV in the
>> > >> > previous iteration. */
>> > >> >
>> > >> > -rtx
>> > >> > -builtin_memset_read_str (void *data, void *prevp,
>> > >> > - HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
>> > >> > - scalar_int_mode mode)
>> > >> > +static rtx
>> > >> > +gen_memset_value_from_prev (void *prevp, scalar_int_mode mode)
>> > >> > {
>> > >> > + rtx target = nullptr;
>> > >> > 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;
>> > >> > +
>> > >> > + rtx prev_rtx = prev->data;
>> > >> > + machine_mode prev_mode = prev->mode;
>> > >> > + unsigned int word_size = GET_MODE_SIZE (word_mode);
>> > >> > + if (word_size < GET_MODE_SIZE (prev->mode)
>> > >> > + && word_size > GET_MODE_SIZE (mode))
>> > >> > + {
>> > >> > + /* First generate subreg of word mode if the previous mode is
>> > >> > + wider than word mode and word mode is wider than MODE. */
>> > >> > + prev_rtx = simplify_gen_subreg (word_mode, prev_rtx,
>> > >> > + prev_mode, 0);
>> > >> > + prev_mode = word_mode;
>> > >> > + }
>> > >> > + if (prev_rtx != nullptr)
>> > >> > + target = simplify_gen_subreg (mode, prev_rtx, prev_mode, 0);
>> > >> > }
>> > >> > + return target;
>> > >> > +}
>> > >> > +
>> > >> > +/* Return the RTL of a register in MODE broadcasted from DATA. */
>> > >> > +
>> > >> > +static rtx
>> > >> > +gen_memset_broadcast (rtx data, scalar_int_mode mode)
>> > >> > +{
>> > >> > + /* Skip if regno_reg_rtx isn't initialized. */
>> > >> > + if (!regno_reg_rtx)
>> > >> > + return nullptr;
>> > >> > +
>> > >> > + rtx target = nullptr;
>> > >> > +
>> > >> > + unsigned int nunits = GET_MODE_SIZE (mode) / GET_MODE_SIZE
>> > >> > (QImode);
>> > >> > + machine_mode vector_mode;
>> > >> > + if (!mode_for_vector (QImode, nunits).exists (&vector_mode))
>> > >> > + gcc_unreachable ();
>> > >>
>> > >> Sorry, I realise it's a bit late to be raising this objection now,
>> > >> but I don't think it's a good idea to use scalar integer modes as
>> > >> a proxy for vector modes. In principle there's no reason why a
>> > >> target has to define an integer mode for every vector mode.
>> > >
>> > > A target always defines the largest integer mode.
>> >
>> > Right. But a target shouldn't *need* to define an integer mode
>> > for every vector mode.
>> >
>> > >> If we want the mode to be a vector then I think the by-pieces
>> > >> infrastructure should be extended to support vectors directly,
>> > >> rather than assuming that each piece can be represented as
>> > >> a scalar_int_mode.
>> > >>
>> > >
>> > > The current by-pieces infrastructure operates on scalar_int_mode.
>> > > Only for memset, there is
>> > >
>> > > /* 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 *data, void *prevp,
>> > > HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
>> > > scalar_int_mode mode)
>> > >
>> > > It is a broadcast. If a target can broadcast a byte to a wider integer,
>> > > can you suggest a way to use it in the current by-pieces infrastructure?
>> >
>> > I meant that we should extend the by-pieces infrastructure so that
>> > it no longer requires scalar_int_mode, rather than work within the
>> > current limits.
>> >
>> > IMO the fact that we're (legitimately) going through vec_duplicate_optab
>>
>> If vec_duplicate_optab is the only blocking issue, can we add an integer
>> broadcast optab? I want to avoid a major surgery just because we
>> don't support integer broadcast from byte.
>>
>> > shows that we really are dealing with vectors here, not integers.
>> >
>>
>> Are you suggesting we should add the optional vector mode
>> support to by-pieces for memset?
>>
>
> Like this?
>
> 1. Replace scalar_int_mode with machine_mode in the by-pieces
> infrastructure to allow non-integer mode.
I guess it might be better to use fixed_size_mode instead of
machine_mode.
> 2. Rename widest_int_mode_for_size to widest_int_or_QI_vector_mode_for_size
> to return QI vector mode for memset.
> 3. Add op_by_pieces_d::smallest_mode_for_size to return the smallest
> integer or QI vector mode.
>
> Thanks.
>
> --
> H.J.
>
> From 171f0a919300a8aac58dfe5fc9904eaa8fe0a05b Mon Sep 17 00:00:00 2001
> From: "H.J. Lu" <hjl.to...@gmail.com>
> Date: Sun, 6 Mar 2016 06:38:21 -0800
> Subject: [PATCH] Add QI vector mode support to by-pieces for memset
>
> 1. Replace scalar_int_mode with machine_mode in the by-pieces
> infrastructure to allow non-integer mode.
> 2. Rename widest_int_mode_for_size to widest_int_or_QI_vector_mode_for_size
> to return QI vector mode for memset.
> 3. Add op_by_pieces_d::smallest_mode_for_size to return the smallest
> integer or QI vector mode.
>
> gcc/
>
> PR middle-end/90773
> * builtins.c (builtin_memcpy_read_str): Change the mode argument
> from scalar_int_mode to machine_mode.
> (builtin_strncpy_read_str): Likewise.
> (gen_memset_value_from_prev): New function.
> (gen_memset_broadcast): Likewise.
> (builtin_memset_read_str): Change the mode argument from
> scalar_int_mode to machine_mode. Use gen_memset_value_from_prev
> and gen_memset_broadcast.
> (builtin_memset_gen_str): Likewise.
> (try_store_by_multiple_pieces): Use by_pieces_constfn to declare
> constfun.
> * builtins.h (builtin_strncpy_read_str): Updated.
> (builtin_memset_read_str): Likewise.
> * expr.c (widest_int_mode_for_size): Renamed to ...
> (widest_int_or_QI_vector_mode_for_size): Add a bool argument to
> indicate if QI vector mode can be used.
> (by_pieces_ninsns): Call widest_int_or_QI_vector_mode_for_size
> instead of widest_int_mode_for_size.
> (pieces_addr::adjust): Change the mode argument from
> scalar_int_mode to machine_mode.
> (op_by_pieces_d): Add a bool member, m_qi_vector_mode, to
> indicate that QI vector mode can be used.
> (op_by_pieces_d::op_by_pieces_d): Add a bool argument to initialize
> m_qi_vector_mode. Call widest_int_or_QI_vector_mode_for_size
> instead of widest_int_mode_for_size.
> (op_by_pieces_d::get_usable_mode): Change the mode argument from
> scalar_int_mode to machine_mode. Call
> widest_int_or_QI_vector_mode_for_size instead of
> widest_int_mode_for_size.
> (op_by_pieces_d::smallest_mode_for_size): New member function
> to return the smallest integer or QI vector mode.
> (op_by_pieces_d::run): Call widest_int_or_QI_vector_mode_for_size
> instead of widest_int_mode_for_size. Call smallest_mode_for_size
> instead of smallest_int_mode_for_size.
> (store_by_pieces_d::store_by_pieces_d): Add a bool argument to
> indicate that QI vector mode can be used and pass it to
> op_by_pieces_d::op_by_pieces_d.
> (can_store_by_pieces): Call widest_int_or_QI_vector_mode_for_size
> instead of widest_int_mode_for_size.
> (store_by_pieces::store_by_pieces): Pass memsetp to
> store_by_pieces_d::store_by_pieces_d.
> (clear_by_pieces_1): Change scalar_int_mode to machine_mode.
> (string_cst_read_str): Change the mode argument from
> scalar_int_mode to machine_mode.
> * expr.h (by_pieces_constfn): Change scalar_int_mode to
> machine_mode.
> (by_pieces_prev): Likewise.
> * target.def (gen_memset_scratch_rtx): New hook.
> * doc/tm.texi.in: Add TARGET_GEN_MEMSET_SCRATCH_RTX.
> * doc/tm.texi: Regenerated.
>
> gcc/testsuite/
>
> * gcc.target/i386/pr100865-3.c: Expect vmovdqu8 instead of
> vmovdqu.
> * gcc.target/i386/pr100865-4b.c: Likewise.
> ---
> gcc/builtins.c | 138 ++++++++++++++-----
> gcc/builtins.h | 4 +-
> gcc/doc/tm.texi | 5 +
> gcc/doc/tm.texi.in | 2 +
> gcc/expr.c | 145 ++++++++++++++------
> gcc/expr.h | 4 +-
> gcc/target.def | 7 +
> gcc/testsuite/gcc.target/i386/pr100865-3.c | 2 +-
> gcc/testsuite/gcc.target/i386/pr100865-4b.c | 2 +-
> 9 files changed, 229 insertions(+), 80 deletions(-)
>
> diff --git a/gcc/builtins.c b/gcc/builtins.c
> index 39ab139b7e1..876378b467c 100644
> --- a/gcc/builtins.c
> +++ b/gcc/builtins.c
> @@ -3890,13 +3890,14 @@ expand_builtin_strnlen (tree exp, rtx target,
> machine_mode target_mode)
>
> static rtx
> builtin_memcpy_read_str (void *data, void *, HOST_WIDE_INT offset,
> - scalar_int_mode mode)
> + machine_mode mode)
> {
> /* The REPresentation pointed to by DATA need not be a nul-terminated
> string but the caller guarantees it's large enough for MODE. */
> const char *rep = (const char *) data;
>
> - return c_readstr (rep + offset, mode, /*nul_terminated=*/false);
> + return c_readstr (rep + offset, as_a <scalar_int_mode> (mode),
> + /*nul_terminated=*/false);
> }
>
> /* LEN specify length of the block of memcpy/memset operation.
> @@ -6478,14 +6479,14 @@ expand_builtin_stpncpy (tree exp, rtx)
>
> rtx
> builtin_strncpy_read_str (void *data, void *, HOST_WIDE_INT offset,
> - scalar_int_mode mode)
> + machine_mode mode)
> {
> const char *str = (const char *) data;
>
> if ((unsigned HOST_WIDE_INT) offset > strlen (str))
> return const0_rtx;
>
> - return c_readstr (str + offset, mode);
> + return c_readstr (str + offset, as_a <scalar_int_mode> (mode));
> }
> /* Helper to check the sizes of sequences and the destination of calls
I think both of these as_a<scalar_int_mode>s should have a comment
explaining that we don't (yet?) consider using vector modes for this
operation.
> @@ -6686,30 +6687,109 @@ expand_builtin_strncpy (tree exp, rtx target)
> return NULL_RTX;
> }
>
> -/* 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
> +/* Return the RTL of a register in MODE generated from PREV in the
> previous iteration. */
>
> -rtx
> -builtin_memset_read_str (void *data, void *prevp,
> - HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
> - scalar_int_mode mode)
> +static rtx
> +gen_memset_value_from_prev (void *prevp, machine_mode mode)
> {
> + rtx target = nullptr;
> by_pieces_prev *prev = (by_pieces_prev *) prevp;
I think it'd be better to pass the proper type instead, since this
function isn't directly implementing a callback interface.
> if (prev != nullptr && prev->data != nullptr)
> {
> /* Use the previous data in the same mode. */
> if (prev->mode == mode)
> return prev->data;
> +
> + rtx prev_rtx = prev->data;
> + machine_mode prev_mode = prev->mode;
> + unsigned int word_size = GET_MODE_SIZE (word_mode);
> + if (word_size < GET_MODE_SIZE (prev->mode).to_constant ()
> + && word_size > GET_MODE_SIZE (mode).to_constant ())
Using fixed_size_mode would also avoid the to_constants here.
UNITS_PER_WORD is more direct/canonical than GET_MODE_SIZE (word_mode).
> + {
> + /* First generate subreg of word mode if the previous mode is
> + wider than word mode and word mode is wider than MODE. */
> + prev_rtx = simplify_gen_subreg (word_mode, prev_rtx,
> + prev_mode, 0);
> + prev_mode = word_mode;
> + }
> + if (prev_rtx != nullptr)
> + target = simplify_gen_subreg (mode, prev_rtx, prev_mode, 0);
This should be lowpart_subreg, since 0 isn't the right offset for
big-endian targets. Using lowpart_subreg should also avoid the need
for the word_size “if” above: lowpart_subreg can handle lowpart subword
subregs of multiword values.
> + }
> + return target;
> +}
> +
> +/* Return the RTL of a register in MODE broadcasted from DATA. */
> +
> +static rtx
> +gen_memset_broadcast (rtx data, machine_mode mode)
> +{
> + /* Skip if regno_reg_rtx isn't initialized or not vector mode. */
Why's the regno_reg_rtx condition needed?
> + if (!regno_reg_rtx || !VECTOR_MODE_P (mode))
> + return nullptr;
> +
> + gcc_assert (GET_MODE_INNER (mode) == QImode);
> +
> + enum insn_code icode = optab_handler (vec_duplicate_optab, mode);
> +
> + gcc_assert (icode != CODE_FOR_nothing);
Might be worth a comment here saying that having vec_duplicate_optab is
a precondition for picking a vector mode.
> +
> + rtx target = targetm.gen_memset_scratch_rtx (mode);
> + if (CONST_INT_P (data))
> + {
> + /* Use the move expander with CONST_VECTOR. */
> + rtx const_vec = gen_const_vec_duplicate (mode, data);
> + emit_move_insn (target, const_vec);
> + }
> + else
> + {
> +
Nit: excess blank line.
> + class expand_operand ops[2];
> + create_output_operand (&ops[0], target, mode);
> + create_input_operand (&ops[1], data, QImode);
> + expand_insn (icode, 2, ops);
> + if (!rtx_equal_p (target, ops[0].value))
> + emit_move_insn (target, ops[0].value);
> }
>
> + return target;
> +}
> +
> +/* 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,
> + machine_mode mode)
> +{
> + rtx target;
> const char *c = (const char *) data;
> - char *p = XALLOCAVEC (char, GET_MODE_SIZE (mode));
> + char *p;
> + unsigned int size = GET_MODE_SIZE (mode).to_constant ();
> +
> + /* Don't use the previous value if size is 1. */
Why not though? The existing code does, and that seems like the right
thing to do when operating on integers.
I can see the check would be a good thing to do if MODE isn't a vector
mode and the previous mode was. Is that the case you're worried about?
If so, that check could go in gen_memset_value_from_prev instead.
> + if (size != 1)
> + {
> + target = gen_memset_value_from_prev (prev, mode);
> + if (target != nullptr)
> + return target;
> +
> + p = XALLOCAVEC (char, GET_MODE_SIZE (QImode));
> + memset (p, *c, GET_MODE_SIZE (QImode));
> + rtx src = c_readstr (p, QImode);
This seems unnecessarily complicated. Couldn't it just be
gen_int_mode (QImode, *c);
instead? There are no endianness concerns for single QI values.
> + target = gen_memset_broadcast (src, mode);
> + if (target != nullptr)
> + return target;
> + }
> +
> + p = XALLOCAVEC (char, size);
>
> - memset (p, *c, GET_MODE_SIZE (mode));
> + memset (p, *c, size);
>
> - return c_readstr (p, mode);
> + return c_readstr (p, as_a <scalar_int_mode> (mode));
> }
>
> /* Callback routine for store_by_pieces. Return the RTL of a register
> @@ -6719,33 +6799,29 @@ 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)
> + machine_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);
> + size = GET_MODE_SIZE (mode).to_constant ();
> if (size == 1)
> return (rtx) data;
>
> + target = gen_memset_value_from_prev (prev, mode);
> + if (target != nullptr)
> + return target;
> +
> + target = gen_memset_broadcast ((rtx) data, mode);
> + if (target != nullptr)
> + return target;
> +
> p = XALLOCAVEC (char, size);
> memset (p, 1, size);
> - coeff = c_readstr (p, mode);
> + coeff = c_readstr (p, as_a <scalar_int_mode> (mode));
>
> target = convert_to_mode (mode, (rtx) data, 1);
> target = expand_mult (mode, target, coeff, NULL_RTX, 1);
> @@ -6849,7 +6925,7 @@ try_store_by_multiple_pieces (rtx to, rtx len, unsigned
> int ctz_len,
> &valc, align, true))
> return false;
>
> - rtx (*constfun) (void *, void *, HOST_WIDE_INT, scalar_int_mode);
> + by_pieces_constfn constfun;
> void *constfundata;
> if (val)
> {
> diff --git a/gcc/builtins.h b/gcc/builtins.h
> index a64ece3f1cd..31d07621750 100644
> --- a/gcc/builtins.h
> +++ b/gcc/builtins.h
> @@ -111,9 +111,9 @@ extern tree mathfn_built_in (tree, enum built_in_function
> fn);
> extern tree mathfn_built_in (tree, combined_fn);
> extern tree mathfn_built_in_type (combined_fn);
> extern rtx builtin_strncpy_read_str (void *, void *, HOST_WIDE_INT,
> - scalar_int_mode);
> + machine_mode);
> extern rtx builtin_memset_read_str (void *, void *, HOST_WIDE_INT,
> - scalar_int_mode);
> + machine_mode);
> extern rtx expand_builtin_saveregs (void);
> extern tree std_build_builtin_va_list (void);
> extern tree std_fn_abi_va_list (tree);
> diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
> index 3ad39443eba..c1995270720 100644
> --- a/gcc/doc/tm.texi
> +++ b/gcc/doc/tm.texi
> @@ -12123,6 +12123,11 @@ 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_GEN_MEMSET_SCRATCH_RTX (machine_mode
> @var{mode})
> +This hook should return an rtx for scratch register in @var{mode} to
> +be used by memset broadcast. The default is @code{gen_reg_rtx}.
This should give a hint why the default might not be appropriate.
> +@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 f881cdabe9e..a6bbf4f2667 100644
> --- a/gcc/doc/tm.texi.in
> +++ b/gcc/doc/tm.texi.in
> @@ -7958,6 +7958,8 @@ lists.
>
> @hook TARGET_GEN_CCMP_NEXT
>
> +@hook TARGET_GEN_MEMSET_SCRATCH_RTX
> +
> @hook TARGET_LOOP_UNROLL_ADJUST
>
> @defmac POWI_MAX_MULTS
> diff --git a/gcc/expr.c b/gcc/expr.c
> index 6a4368113c4..92dbf47194e 100644
> --- a/gcc/expr.c
> +++ b/gcc/expr.c
> @@ -769,15 +769,36 @@ alignment_for_piecewise_move (unsigned int max_pieces,
> unsigned int align)
> return align;
> }
>
> -/* Return the widest integer mode that is narrower than SIZE bytes. */
> +/* Return the widest integer or QI vector mode that is narrower than
> + SIZE bytes. */
>
> -static scalar_int_mode
> -widest_int_mode_for_size (unsigned int size)
> +static machine_mode
> +widest_int_or_QI_vector_mode_for_size (unsigned int size,
> + bool qi_vector)
> {
> - scalar_int_mode result = NARROWEST_INT_MODE;
> + machine_mode result = NARROWEST_INT_MODE;
>
> gcc_checking_assert (size > 1);
>
> + /* Use QI vector only if size is wider than a WORD. */
> + if (qi_vector && size > GET_MODE_SIZE (word_mode))
> + {
> + machine_mode mode;
> + FOR_EACH_MODE_IN_CLASS (mode, MODE_VECTOR_INT)
> + if (GET_MODE_INNER (mode) == QImode
> + && GET_MODE_SIZE (mode).is_constant ())
> + {
> + if (GET_MODE_SIZE (mode).to_constant () >= size)
> + break;
> + if (optab_handler (vec_duplicate_optab, mode)
> + != CODE_FOR_nothing)
> + result = mode;
> + }
> +
> + if (result != NARROWEST_INT_MODE)
> + return result;
> + }
> +
> opt_scalar_int_mode tmode;
> FOR_EACH_MODE_IN_CLASS (tmode, MODE_INT)
> if (GET_MODE_SIZE (tmode.require ()) < size)
> @@ -815,16 +836,18 @@ by_pieces_ninsns (unsigned HOST_WIDE_INT l, unsigned
> int align,
> unsigned int max_size, by_pieces_operation op)
> {
> unsigned HOST_WIDE_INT n_insns = 0;
> - scalar_int_mode mode;
> + machine_mode mode;
>
> if (targetm.overlap_op_by_pieces_p () && op != COMPARE_BY_PIECES)
> {
> /* NB: Round up L and ALIGN to the widest integer mode for
> MAX_SIZE. */
> - mode = widest_int_mode_for_size (max_size);
> + mode = widest_int_or_QI_vector_mode_for_size (max_size,
> + op == SET_BY_PIECES);
> if (optab_handler (mov_optab, mode) != CODE_FOR_nothing)
> {
> - unsigned HOST_WIDE_INT up = ROUND_UP (l, GET_MODE_SIZE (mode));
> + unsigned HOST_WIDE_INT up = ROUND_UP (l,
> + GET_MODE_SIZE
> (mode).to_constant ());
> if (up > l)
> l = up;
> align = GET_MODE_ALIGNMENT (mode);
> @@ -835,10 +858,11 @@ by_pieces_ninsns (unsigned HOST_WIDE_INT l, unsigned
> int align,
>
> while (max_size > 1 && l > 0)
> {
> - mode = widest_int_mode_for_size (max_size);
> + mode = widest_int_or_QI_vector_mode_for_size (max_size,
> + op == SET_BY_PIECES);
> enum insn_code icode;
>
> - unsigned int modesize = GET_MODE_SIZE (mode);
> + unsigned int modesize = GET_MODE_SIZE (mode).to_constant ();
>
> icode = optab_handler (mov_optab, mode);
> if (icode != CODE_FOR_nothing && align >= GET_MODE_ALIGNMENT (mode))
> @@ -903,8 +927,7 @@ class pieces_addr
> void *m_cfndata;
> public:
> pieces_addr (rtx, bool, by_pieces_constfn, void *);
> - rtx adjust (scalar_int_mode, HOST_WIDE_INT,
> - by_pieces_prev * = nullptr);
> + rtx adjust (machine_mode, HOST_WIDE_INT, by_pieces_prev * = nullptr);
> void increment_address (HOST_WIDE_INT);
> void maybe_predec (HOST_WIDE_INT);
> void maybe_postinc (HOST_WIDE_INT);
> @@ -1006,7 +1029,7 @@ pieces_addr::decide_autoinc (machine_mode ARG_UNUSED
> (mode), bool reverse,
> but we still modify the MEM's properties. */
>
> rtx
> -pieces_addr::adjust (scalar_int_mode mode, HOST_WIDE_INT offset,
> +pieces_addr::adjust (machine_mode mode, HOST_WIDE_INT offset,
> by_pieces_prev *prev)
> {
> if (m_constfn)
> @@ -1060,7 +1083,8 @@ pieces_addr::maybe_postinc (HOST_WIDE_INT size)
> class op_by_pieces_d
> {
> private:
> - scalar_int_mode get_usable_mode (scalar_int_mode mode, unsigned int);
> + machine_mode get_usable_mode (machine_mode, unsigned int);
> + machine_mode smallest_mode_for_size (unsigned int);
>
> protected:
> pieces_addr m_to, m_from;
> @@ -1073,6 +1097,8 @@ class op_by_pieces_d
> bool m_push;
> /* True if targetm.overlap_op_by_pieces_p () returns true. */
> bool m_overlap_op_by_pieces;
> + /* True if QI vector mode can be used. */
> + bool m_qi_vector_mode;
>
> /* Virtual functions, overriden by derived classes for the specific
> operation. */
> @@ -1084,7 +1110,8 @@ class op_by_pieces_d
>
> public:
> op_by_pieces_d (rtx, bool, rtx, bool, by_pieces_constfn, void *,
> - unsigned HOST_WIDE_INT, unsigned int, bool);
> + unsigned HOST_WIDE_INT, unsigned int, bool,
> + bool = false);
> void run ();
> };
>
> @@ -1099,11 +1126,12 @@ op_by_pieces_d::op_by_pieces_d (rtx to, bool to_load,
> by_pieces_constfn from_cfn,
> void *from_cfn_data,
> unsigned HOST_WIDE_INT len,
> - unsigned int align, bool push)
> + unsigned int align, bool push,
> + bool qi_vector_mode)
> : m_to (to, to_load, NULL, NULL),
> m_from (from, from_load, from_cfn, from_cfn_data),
> m_len (len), m_max_size (MOVE_MAX_PIECES + 1),
> - m_push (push)
> + m_push (push), m_qi_vector_mode (qi_vector_mode)
> {
> int toi = m_to.get_addr_inc ();
> int fromi = m_from.get_addr_inc ();
> @@ -1124,7 +1152,9 @@ op_by_pieces_d::op_by_pieces_d (rtx to, bool to_load,
> if (by_pieces_ninsns (len, align, m_max_size, MOVE_BY_PIECES) > 2)
> {
> /* Find the mode of the largest comparison. */
> - scalar_int_mode mode = widest_int_mode_for_size (m_max_size);
> + machine_mode mode
> + = widest_int_or_QI_vector_mode_for_size (m_max_size,
> + m_qi_vector_mode);
>
> m_from.decide_autoinc (mode, m_reverse, len);
> m_to.decide_autoinc (mode, m_reverse, len);
> @@ -1139,22 +1169,42 @@ op_by_pieces_d::op_by_pieces_d (rtx to, bool to_load,
> /* This function returns the largest usable integer mode for LEN bytes
> whose size is no bigger than size of MODE. */
>
> -scalar_int_mode
> -op_by_pieces_d::get_usable_mode (scalar_int_mode mode, unsigned int len)
> +machine_mode
> +op_by_pieces_d::get_usable_mode (machine_mode mode, unsigned int len)
> {
> unsigned int size;
> do
> {
> - size = GET_MODE_SIZE (mode);
> + size = GET_MODE_SIZE (mode).to_constant ();
> if (len >= size && prepare_mode (mode, m_align))
> break;
> - /* NB: widest_int_mode_for_size checks SIZE > 1. */
> - mode = widest_int_mode_for_size (size);
> + /* NB: widest_int_or_QI_vector_mode_for_size checks SIZE > 1. */
> + mode = widest_int_or_QI_vector_mode_for_size (size,
> + m_qi_vector_mode);
> }
> while (1);
> return mode;
> }
>
> +/* Return the smallest integer or QI vector mode that is not narrower
> + than SIZE bits. */
> +
> +machine_mode
> +op_by_pieces_d::smallest_mode_for_size (unsigned int size)
> +{
> + /* Use QI vector only for > size of WORD. */
> + if (m_qi_vector_mode && size > GET_MODE_PRECISION (word_mode))
> + {
> + machine_mode mode;
> + FOR_EACH_MODE_IN_CLASS (mode, MODE_VECTOR_INT)
> + if (GET_MODE_INNER (mode) == QImode
> + && known_ge (GET_MODE_PRECISION (mode), size))
> + return mode;
Shouldn't this also test for vec_duplicate_optab? I guess you're
hoping that the previous register will be reused via a lowpart,
but since that's up to the callbacks, I think we should be
conservative here.
Alternatively, we could bypass the callbacks when this code is used.
Thanks,
Richard
> + }
> +
> + return smallest_int_mode_for_size (size);
> +}
> +
> /* This function contains the main loop used for expanding a block
> operation. First move what we can in the largest integer mode,
> then go to successively smaller modes. For every access, call
> @@ -1166,8 +1216,10 @@ op_by_pieces_d::run ()
> if (m_len == 0)
> return;
>
> - /* NB: widest_int_mode_for_size checks M_MAX_SIZE > 1. */
> - scalar_int_mode mode = widest_int_mode_for_size (m_max_size);
> + /* NB: widest_int_or_QI_vector_mode_for_size checks M_MAX_SIZE > 1. */
> + machine_mode mode
> + = widest_int_or_QI_vector_mode_for_size (m_max_size,
> + m_qi_vector_mode);
> mode = get_usable_mode (mode, m_len);
>
> by_pieces_prev to_prev = { nullptr, mode };
> @@ -1175,7 +1227,7 @@ op_by_pieces_d::run ()
>
> do
> {
> - unsigned int size = GET_MODE_SIZE (mode);
> + unsigned int size = GET_MODE_SIZE (mode).to_constant ();
> rtx to1 = NULL_RTX, from1;
>
> while (m_len >= size)
> @@ -1214,9 +1266,10 @@ op_by_pieces_d::run ()
> /* NB: Generate overlapping operations if it is not a stack
> push since stack push must not overlap. Get the smallest
> integer mode for M_LEN bytes. */
> - mode = smallest_int_mode_for_size (m_len * BITS_PER_UNIT);
> - mode = get_usable_mode (mode, GET_MODE_SIZE (mode));
> - int gap = GET_MODE_SIZE (mode) - m_len;
> + mode = smallest_mode_for_size (m_len * BITS_PER_UNIT);
> + unsigned int mode_size = GET_MODE_SIZE (mode).to_constant ();
> + mode = get_usable_mode (mode, mode_size);
> + int gap = mode_size - m_len;
> if (gap > 0)
> {
> /* If size of MODE > M_LEN, generate the last operation
> @@ -1231,8 +1284,9 @@ op_by_pieces_d::run ()
> }
> else
> {
> - /* NB: widest_int_mode_for_size checks SIZE > 1. */
> - mode = widest_int_mode_for_size (size);
> + /* NB: widest_int_or_QI_vector_mode_for_size checks SIZE > 1. */
> + mode = widest_int_or_QI_vector_mode_for_size (size,
> + m_qi_vector_mode);
> mode = get_usable_mode (mode, m_len);
> }
> }
> @@ -1355,9 +1409,10 @@ class store_by_pieces_d : public op_by_pieces_d
>
> public:
> store_by_pieces_d (rtx to, by_pieces_constfn cfn, void *cfn_data,
> - unsigned HOST_WIDE_INT len, unsigned int align)
> + unsigned HOST_WIDE_INT len, unsigned int align,
> + bool qi_vector_mode = false)
> : op_by_pieces_d (to, false, NULL_RTX, true, cfn, cfn_data, len,
> - align, false)
> + align, false, qi_vector_mode)
> {
> }
> rtx finish_retmode (memop_ret);
> @@ -1446,13 +1501,14 @@ can_store_by_pieces (unsigned HOST_WIDE_INT len,
> max_size = STORE_MAX_PIECES + 1;
> while (max_size > 1 && l > 0)
> {
> - scalar_int_mode mode = widest_int_mode_for_size (max_size);
> + machine_mode mode
> + = widest_int_or_QI_vector_mode_for_size (max_size, memsetp);
>
> icode = optab_handler (mov_optab, mode);
> if (icode != CODE_FOR_nothing
> && align >= GET_MODE_ALIGNMENT (mode))
> {
> - unsigned int size = GET_MODE_SIZE (mode);
> + unsigned int size = GET_MODE_SIZE (mode).to_constant ();
>
> while (l >= size)
> {
> @@ -1470,7 +1526,7 @@ can_store_by_pieces (unsigned HOST_WIDE_INT len,
> }
> }
>
> - max_size = GET_MODE_SIZE (mode);
> + max_size = GET_MODE_SIZE (mode).to_constant ();
> }
>
> /* The code above should have handled everything. */
> @@ -1504,7 +1560,8 @@ store_by_pieces (rtx to, unsigned HOST_WIDE_INT len,
> memsetp ? SET_BY_PIECES : STORE_BY_PIECES,
> optimize_insn_for_speed_p ()));
>
> - store_by_pieces_d data (to, constfun, constfundata, len, align);
> + store_by_pieces_d data (to, constfun, constfundata, len, align,
> + memsetp);
> data.run ();
>
> if (retmode != RETURN_BEGIN)
> @@ -1517,7 +1574,7 @@ store_by_pieces (rtx to, unsigned HOST_WIDE_INT len,
> Return const0_rtx unconditionally. */
>
> static rtx
> -clear_by_pieces_1 (void *, void *, HOST_WIDE_INT, scalar_int_mode)
> +clear_by_pieces_1 (void *, void *, HOST_WIDE_INT, machine_mode)
> {
> return const0_rtx;
> }
> @@ -5754,7 +5811,7 @@ emit_storent_insn (rtx to, rtx from)
>
> static rtx
> string_cst_read_str (void *data, void *, HOST_WIDE_INT offset,
> - scalar_int_mode mode)
> + machine_mode mode)
> {
> tree str = (tree) data;
>
> @@ -5762,17 +5819,19 @@ string_cst_read_str (void *data, void *,
> HOST_WIDE_INT offset,
> if (offset >= TREE_STRING_LENGTH (str))
> return const0_rtx;
>
> - if ((unsigned HOST_WIDE_INT) offset + GET_MODE_SIZE (mode)
> + unsigned int size = GET_MODE_SIZE (mode).to_constant ();
> + if ((unsigned HOST_WIDE_INT) offset + size
> > (unsigned HOST_WIDE_INT) TREE_STRING_LENGTH (str))
> {
> - char *p = XALLOCAVEC (char, GET_MODE_SIZE (mode));
> + char *p = XALLOCAVEC (char, size);
> size_t l = TREE_STRING_LENGTH (str) - offset;
> memcpy (p, TREE_STRING_POINTER (str) + offset, l);
> - memset (p + l, '\0', GET_MODE_SIZE (mode) - l);
> - return c_readstr (p, mode, false);
> + memset (p + l, '\0', size - l);
> + return c_readstr (p, as_a <scalar_int_mode> (mode), false);
> }
>
> - return c_readstr (TREE_STRING_POINTER (str) + offset, mode, false);
> + return c_readstr (TREE_STRING_POINTER (str) + offset,
> + as_a <scalar_int_mode> (mode), false);
> }
>
> /* Generate code for computing expression EXP,
> diff --git a/gcc/expr.h b/gcc/expr.h
> index a4f44265759..552645e4403 100644
> --- a/gcc/expr.h
> +++ b/gcc/expr.h
> @@ -108,13 +108,13 @@ enum block_op_methods
> };
>
> typedef rtx (*by_pieces_constfn) (void *, void *, HOST_WIDE_INT,
> - scalar_int_mode);
> + machine_mode);
>
> /* The second pointer passed to by_pieces_constfn. */
> struct by_pieces_prev
> {
> rtx data;
> - scalar_int_mode mode;
> + machine_mode mode;
> };
>
> extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
> diff --git a/gcc/target.def b/gcc/target.def
> index 2e40448e6c5..cc4aa3a4212 100644
> --- a/gcc/target.def
> +++ b/gcc/target.def
> @@ -2726,6 +2726,13 @@ DEFHOOK
> rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code, tree
> op0, tree op1, int bit_code),
> NULL)
>
> +DEFHOOK
> +(gen_memset_scratch_rtx,
> + "This hook should return an rtx for scratch register in @var{mode} to\n\
> +be used by memset broadcast. The default is @code{gen_reg_rtx}.",
> + rtx, (machine_mode mode),
> + gen_reg_rtx)
> +
> /* Return a new value for loop unroll size. */
> DEFHOOK
> (loop_unroll_adjust,
> diff --git a/gcc/testsuite/gcc.target/i386/pr100865-3.c
> b/gcc/testsuite/gcc.target/i386/pr100865-3.c
> index b6dbcf7809b..007e79f91b0 100644
> --- a/gcc/testsuite/gcc.target/i386/pr100865-3.c
> +++ b/gcc/testsuite/gcc.target/i386/pr100865-3.c
> @@ -10,6 +10,6 @@ foo (void)
> }
>
> /* { dg-final { scan-assembler-times "vpbroadcastb\[\\t \]+%(?:r|e)\[^\n\]*,
> %xmm\[0-9\]+" 1 } } */
> -/* { dg-final { scan-assembler-times "vmovdqu\[\\t \]%xmm\[0-9\]+,
> \\(%\[\^,\]+\\)" 1 } } */
> +/* { dg-final { scan-assembler-times "vmovdqu8\[\\t \]%xmm\[0-9\]+,
> \\(%\[\^,\]+\\)" 1 } } */
> /* { dg-final { scan-assembler-not "vpbroadcastb\[\\t \]+%xmm\[0-9\]+,
> %xmm\[0-9\]+" } } */
> /* { dg-final { scan-assembler-not "vmovdqa" } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pr100865-4b.c
> b/gcc/testsuite/gcc.target/i386/pr100865-4b.c
> index f41e6147b4c..1e50dc842bc 100644
> --- a/gcc/testsuite/gcc.target/i386/pr100865-4b.c
> +++ b/gcc/testsuite/gcc.target/i386/pr100865-4b.c
> @@ -4,6 +4,6 @@
> #include "pr100865-4a.c"
>
> /* { dg-final { scan-assembler-times "vpbroadcastb\[\\t \]+%(?:r|e)\[^\n\]*,
> %xmm\[0-9\]+" 1 } } */
> -/* { dg-final { scan-assembler-times "vmovdqu\[\\t \]%xmm\[0-9\]+, " 4 } } */
> +/* { dg-final { scan-assembler-times "vmovdqu8\[\\t \]%xmm\[0-9\]+, " 4 } }
> */
> /* { dg-final { scan-assembler-not "vpbroadcastb\[\\t \]+%xmm\[0-9\]+,
> %xmm\[0-9\]+" } } */
> /* { dg-final { scan-assembler-not "vmovdqa" } } */
