Thanks for the update. The comments below are mostly asking for
cosmetic changes.
HAO CHEN GUI <guih...@linux.ibm.com> writes:
> Hi,
> Vector mode instructions are efficient for compare on some targets.
> This patch enables vector mode for compare_by_pieces. Currently,
> vector mode is enabled for compare, set and clear. Helper function
> "qi_vector_p" decides if vector mode is enabled for certain by pieces
> operation. optabs_checking checks if optabs are available for the
> mode and certain by pieces operations. Both of them are called in
> fixed_size_mode finding functions. A member is added to class
> op_by_pieces_d in order to record the type of by pieces operations.
>
> The test case is in the second patch which is rs6000 specific.
>
> Compared to last version, the main change is to create two helper
> functions and call them in mode finding function.
>
> Bootstrapped and tested on x86 and powerpc64-linux BE and LE with no
> regressions.
>
> Thanks
> Gui Haochen
>
> ChangeLog
> Expand: Enable vector mode for pieces compares
>
> Vector mode compare instructions are efficient for equality compare on
> rs6000. This patch refactors the codes of pieces operation to enable
> vector mode for compare.
>
> gcc/
> PR target/111449
> * expr.cc (qi_vector_p): New function to indicate if vector mode
> is enabled for certain by pieces operations.
> (optabs_checking): New function to check if optabs are available
> for certain by pieces operations.
> (widest_fixed_size_mode_for_size): Replace the second argument
> with the type of by pieces operations. Call qi_vector_p to check
> if vector mode is enable. Call optabs_checking to check if optabs
> are available for the candidate vector mode.
> (by_pieces_ninsns): Pass the type of by pieces operation to
> widest_fixed_size_mode_for_size.
> (class op_by_pieces_d): Add a protected member m_op to record the
> type of by pieces operations. Declare member function
> fixed_size_mode widest_fixed_size_mode_for_size.
> (op_by_pieces_d::op_by_pieces_d): Change last argument to the type
> of by pieces operations, initialize m_op with it. Call non-member
> function widest_fixed_size_mode_for_size.
> (op_by_pieces_d::get_usable_mode): Call member function
> widest_fixed_size_mode_for_size.
> (op_by_pieces_d::smallest_fixed_size_mode_for_size): Call
> qi_vector_p to check if vector mode is enable. Call
> optabs_checking to check if optabs are available for the candidate
> vector mode.
> (op_by_pieces_d::run): Call member function
> widest_fixed_size_mode_for_size.
> (op_by_pieces_d::widest_fixed_size_mode_for_size): Implement.
> (move_by_pieces_d::move_by_pieces_d): Set m_op to MOVE_BY_PIECES.
> (store_by_pieces_d::store_by_pieces_d): Set m_op with the op.
> (can_store_by_pieces): Pass the type of by pieces operations to
> widest_fixed_size_mode_for_size.
> (clear_by_pieces): Initialize class store_by_pieces_d with
> CLEAR_BY_PIECES.
> (compare_by_pieces_d::compare_by_pieces_d): Set m_op to
> COMPARE_BY_PIECES.
>
> patch.diff
> diff --git a/gcc/expr.cc b/gcc/expr.cc
> index d87346dc07f..8ec3f5465a9 100644
> --- a/gcc/expr.cc
> +++ b/gcc/expr.cc
> @@ -988,18 +988,43 @@ alignment_for_piecewise_move (unsigned int max_pieces,
> unsigned int align)
> return align;
> }
>
> -/* Return the widest QI vector, if QI_MODE is true, or integer mode
> - that is narrower than SIZE bytes. */
> +/* Return true if vector mode is enabled for the op. */
Maybe:
/* Return true if we know how to implement OP using vectors of bytes. */
"enabled" would normally imply target support.
> +static bool
> +qi_vector_p (by_pieces_operation op)
And maybe call the function "can_use_qi_vectors"
> +{
> + return (op == COMPARE_BY_PIECES
> + || op == SET_BY_PIECES
> + || op == CLEAR_BY_PIECES);
> +}
> +
> +/* Return true if optabs are available for the mode and by pieces
> + operations. */
Maybe:
/* Return true if the target supports operation OP using vector mode MODE. */
> +static bool
> +optabs_checking (fixed_size_mode mode, by_pieces_operation op)
And maybe call the function "qi_vector_mode_supported_p".
> +{
> + if ((op == SET_BY_PIECES || op == CLEAR_BY_PIECES)
> + && optab_handler (vec_duplicate_optab, mode) != CODE_FOR_nothing)
> + return true;
> + else if (op == COMPARE_BY_PIECES
> + && optab_handler (mov_optab, mode) != CODE_FOR_nothing
> + && can_compare_p (EQ, mode, ccp_jump))
> + return true;
> +
> + return false;
> +}
> +
> +/* Return the widest QI vector, if vector mode is enabled for the op,
> + or integer mode that is narrower than SIZE bytes. */
Maybe:
/* Return the widest mode that can be used to perform part of
an operation OP on SIZE bytes. Try to use QI vector modes
where possible. */
>
> static fixed_size_mode
> -widest_fixed_size_mode_for_size (unsigned int size, bool qi_vector)
> +widest_fixed_size_mode_for_size (unsigned int size, by_pieces_operation op)
> {
> fixed_size_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 > UNITS_PER_WORD)
> + if (qi_vector_p (op) && size > UNITS_PER_WORD)
> {
> machine_mode mode;
> fixed_size_mode candidate;
> @@ -1009,8 +1034,7 @@ widest_fixed_size_mode_for_size (unsigned int size,
> bool qi_vector)
> {
> if (GET_MODE_SIZE (candidate) >= size)
> break;
> - if (optab_handler (vec_duplicate_optab, candidate)
> - != CODE_FOR_nothing)
> + if (optabs_checking (candidate, op))
> result = candidate;
> }
>
> @@ -1061,8 +1085,7 @@ by_pieces_ninsns (unsigned HOST_WIDE_INT l, unsigned
> int align,
> {
> /* NB: Round up L and ALIGN to the widest integer mode for
> MAX_SIZE. */
> - mode = widest_fixed_size_mode_for_size (max_size,
> - op == SET_BY_PIECES);
> + mode = widest_fixed_size_mode_for_size (max_size, op);
> if (optab_handler (mov_optab, mode) != CODE_FOR_nothing)
> {
> unsigned HOST_WIDE_INT up = ROUND_UP (l, GET_MODE_SIZE (mode));
> @@ -1076,8 +1099,7 @@ by_pieces_ninsns (unsigned HOST_WIDE_INT l, unsigned
> int align,
>
> while (max_size > 1 && l > 0)
> {
> - mode = widest_fixed_size_mode_for_size (max_size,
> - op == SET_BY_PIECES);
> + mode = widest_fixed_size_mode_for_size (max_size, op);
> enum insn_code icode;
>
> unsigned int modesize = GET_MODE_SIZE (mode);
> @@ -1319,6 +1341,8 @@ class op_by_pieces_d
> bool m_overlap_op_by_pieces;
> /* True if QI vector mode can be used. */
> bool m_qi_vector_mode;
We should be able to remove this field.
> + /* The types of by pieces operations. */
Maybe: "The type of operation that we're performing."
> + by_pieces_operation m_op;
>
> /* Virtual functions, overriden by derived classes for the specific
> operation. */
> @@ -1327,11 +1351,12 @@ class op_by_pieces_d
> virtual void finish_mode (machine_mode)
> {
> }
> + fixed_size_mode widest_fixed_size_mode_for_size (unsigned int);
This function should no longer be needed.
> public:
> op_by_pieces_d (unsigned int, rtx, bool, rtx, bool, by_pieces_constfn,
> void *, unsigned HOST_WIDE_INT, unsigned int, bool,
> - bool = false);
> + by_pieces_operation);
> void run ();
> };
>
> @@ -1349,11 +1374,11 @@ op_by_pieces_d::op_by_pieces_d (unsigned int
> max_pieces, rtx to,
> void *from_cfn_data,
> unsigned HOST_WIDE_INT len,
> unsigned int align, bool push,
> - bool qi_vector_mode)
> + by_pieces_operation op)
> : m_to (to, to_load, NULL, NULL),
> m_from (from, from_load, from_cfn, from_cfn_data),
> m_len (len), m_max_size (max_pieces + 1),
> - m_push (push), m_qi_vector_mode (qi_vector_mode)
> + m_push (push), m_op (op)
> {
> int toi = m_to.get_addr_inc ();
> int fromi = m_from.get_addr_inc ();
> @@ -1375,8 +1400,7 @@ op_by_pieces_d::op_by_pieces_d (unsigned int
> max_pieces, rtx to,
> {
> /* Find the mode of the largest comparison. */
> fixed_size_mode mode
> - = widest_fixed_size_mode_for_size (m_max_size,
> - m_qi_vector_mode);
> + = ::widest_fixed_size_mode_for_size (m_max_size, m_op);
>
> m_from.decide_autoinc (mode, m_reverse, len);
> m_to.decide_autoinc (mode, m_reverse, len);
> @@ -1401,7 +1425,7 @@ op_by_pieces_d::get_usable_mode (fixed_size_mode mode,
> unsigned int len)
> if (len >= size && prepare_mode (mode, m_align))
> break;
> /* widest_fixed_size_mode_for_size checks SIZE > 1. */
> - mode = widest_fixed_size_mode_for_size (size, m_qi_vector_mode);
> + mode = widest_fixed_size_mode_for_size (size);
It looks like this could be:
mode = widest_fixed_size_mode_for_size (size, m_op);
> }
> while (1);
> return mode;
> @@ -1414,7 +1438,7 @@ fixed_size_mode
> op_by_pieces_d::smallest_fixed_size_mode_for_size (unsigned int size)
> {
> /* Use QI vector only for > size of WORD. */
> - if (m_qi_vector_mode && size > UNITS_PER_WORD)
> + if (qi_vector_p (m_op) && size > UNITS_PER_WORD)
> {
> machine_mode mode;
> fixed_size_mode candidate;
> @@ -1427,8 +1451,7 @@ op_by_pieces_d::smallest_fixed_size_mode_for_size
> (unsigned int size)
> break;
>
> if (GET_MODE_SIZE (candidate) >= size
> - && (optab_handler (vec_duplicate_optab, candidate)
> - != CODE_FOR_nothing))
> + && optabs_checking (candidate, m_op))
> return candidate;
> }
> }
> @@ -1451,7 +1474,7 @@ op_by_pieces_d::run ()
>
> /* widest_fixed_size_mode_for_size checks M_MAX_SIZE > 1. */
> fixed_size_mode mode
> - = widest_fixed_size_mode_for_size (m_max_size, m_qi_vector_mode);
> + = widest_fixed_size_mode_for_size (m_max_size);
Same here.
> mode = get_usable_mode (mode, length);
>
> by_pieces_prev to_prev = { nullptr, mode };
> @@ -1516,14 +1539,19 @@ op_by_pieces_d::run ()
> else
> {
> /* widest_fixed_size_mode_for_size checks SIZE > 1. */
> - mode = widest_fixed_size_mode_for_size (size,
> - m_qi_vector_mode);
> + mode = widest_fixed_size_mode_for_size (size);
Here too.
> mode = get_usable_mode (mode, length);
> }
> }
> while (1);
> }
>
> +fixed_size_mode
> +op_by_pieces_d::widest_fixed_size_mode_for_size (unsigned int size)
> +{
> + return ::widest_fixed_size_mode_for_size (size, m_op);
> +}
> +
> /* Derived class from op_by_pieces_d, providing support for block move
> operations. */
>
> @@ -1543,7 +1571,7 @@ class move_by_pieces_d : public op_by_pieces_d
> move_by_pieces_d (rtx to, rtx from, unsigned HOST_WIDE_INT len,
> unsigned int align)
> : op_by_pieces_d (MOVE_MAX_PIECES, to, false, from, true, NULL,
> - NULL, len, align, PUSHG_P (to))
> + NULL, len, align, PUSHG_P (to), MOVE_BY_PIECES)
> {
> }
> rtx finish_retmode (memop_ret);
> @@ -1632,15 +1660,16 @@ move_by_pieces (rtx to, rtx from, unsigned
> HOST_WIDE_INT len,
> class store_by_pieces_d : public op_by_pieces_d
> {
> insn_gen_fn m_gen_fun;
> +
> void generate (rtx, rtx, machine_mode) final override;
> bool prepare_mode (machine_mode, unsigned int) final override;
>
> public:
> store_by_pieces_d (rtx to, by_pieces_constfn cfn, void *cfn_data,
> unsigned HOST_WIDE_INT len, unsigned int align,
> - bool qi_vector_mode)
> + by_pieces_operation op)
> : op_by_pieces_d (STORE_MAX_PIECES, to, false, NULL_RTX, true, cfn,
> - cfn_data, len, align, false, qi_vector_mode)
> + cfn_data, len, align, false, op)
> {
> }
> rtx finish_retmode (memop_ret);
> @@ -1730,7 +1759,8 @@ can_store_by_pieces (unsigned HOST_WIDE_INT len,
> while (max_size > 1 && l > 0)
> {
> fixed_size_mode mode
> - = widest_fixed_size_mode_for_size (max_size, memsetp);
> + = widest_fixed_size_mode_for_size (max_size,
> + memsetp ? SET_BY_PIECES : STORE_BY_PIECES);
Stricly speaking, this doesn't follow the coding convention. Maybe:
auto op = memsetp ? SET_BY_PIECES : STORE_BY_PIECES;
auto mode = widest_fixed_size_mode_for_size (max_size, op);
Looks good otherwise. Pretty sure the next review iteration
will be the last. :)
Richard
>
> icode = optab_handler (mov_optab, mode);
> if (icode != CODE_FOR_nothing
> @@ -1793,7 +1823,7 @@ store_by_pieces (rtx to, unsigned HOST_WIDE_INT len,
> optimize_insn_for_speed_p ()));
>
> store_by_pieces_d data (to, constfun, constfundata, len, align,
> - memsetp);
> + memsetp ? SET_BY_PIECES : STORE_BY_PIECES);
> data.run ();
>
> if (retmode != RETURN_BEGIN)
> @@ -1814,7 +1844,7 @@ clear_by_pieces (rtx to, unsigned HOST_WIDE_INT len,
> unsigned int align)
> /* Use builtin_memset_read_str to support vector mode broadcast. */
> char c = 0;
> store_by_pieces_d data (to, builtin_memset_read_str, &c, len, align,
> - true);
> + CLEAR_BY_PIECES);
> data.run ();
> }
>
> @@ -1832,12 +1862,13 @@ class compare_by_pieces_d : public op_by_pieces_d
> void generate (rtx, rtx, machine_mode) final override;
> bool prepare_mode (machine_mode, unsigned int) final override;
> void finish_mode (machine_mode) final override;
> +
> public:
> compare_by_pieces_d (rtx op0, rtx op1, by_pieces_constfn op1_cfn,
> void *op1_cfn_data, HOST_WIDE_INT len, int align,
> rtx_code_label *fail_label)
> : op_by_pieces_d (COMPARE_MAX_PIECES, op0, true, op1, true, op1_cfn,
> - op1_cfn_data, len, align, false)
> + op1_cfn_data, len, align, false, COMPARE_BY_PIECES)
> {
> m_fail_label = fail_label;
> }
> @@ -1943,6 +1974,7 @@ compare_by_pieces (rtx arg0, rtx arg1, unsigned
> HOST_WIDE_INT len,
>
> return target;
> }
> +
>
> /* Emit code to move a block Y to a block X. This may be done with
> string-move instructions, with multiple scalar move instructions,
