Re: [PATCH] VECT: Add WHILE_LEN pattern for decrement IV support for auto-vectorization

[Richard Biener <rguenther@suse.de>]

On Tue, 11 Apr 2023, Richard Sandiford wrote:

> "juzhe.zhong@rivai.ai" <juzhe.zhong@rivai.ai> writes:
> > Hi, Richards. 
> > Kindly Ping this patch. 
> > This is the most important patch for RVV auto-vectorization support.
> > Bootstraped on X86 has passed.
> 
> Can it wait for GCC 14?  It doesn't seem like stage 4 material.
> 
> Also, pinging after 5 days seems a bit soon.  It's been a 4-day
> holiday weekend for much of Europe.

Also can you explain why using WHILE_ULT is not possible?  (I've
successfully - to some extent - done that for AVX512 for example)

The patch lacks the description of what WHILE_LEN actually is.

Richard.

> Thanks,
> Richard
> 
> > Feel free to comments.
> >
> > Thanks.
> >
> >
> > juzhe.zhong@rivai.ai
> >  
> > From: juzhe.zhong
> > Date: 2023-04-07 09:47
> > To: gcc-patches
> > CC: richard.sandiford; rguenther; jeffreyalaw; Juzhe-Zhong
> > Subject: [PATCH] VECT: Add WHILE_LEN pattern for decrement IV support for auto-vectorization
> > From: Juzhe-Zhong <juzhe.zhong@rivai.ai>
> >  
> > This patch is to add WHILE_LEN pattern.
> > It's inspired by RVV ISA simple "vvaddint32.s" example:
> > https://github.com/riscv/riscv-v-spec/blob/master/example/vvaddint32.s
> >  
> > More details are in "vect_set_loop_controls_by_while_len" implementation
> > and comments.
> >  
> > Consider such following case:
> > #define N 16
> > int src[N];
> > int dest[N];
> >  
> > void
> > foo (int n)
> > {
> >   for (int i = 0; i < n; i++)
> >     dest[i] = src[i];
> > }
> >  
> > -march=rv64gcv -O3 --param riscv-autovec-preference=scalable -fno-vect-cost-model -fno-tree-loop-distribute-patterns:
> >  
> > foo:        
> >         ble     a0,zero,.L1
> >         lui     a4,%hi(.LANCHOR0)
> >         addi    a4,a4,%lo(.LANCHOR0)
> >         addi    a3,a4,64
> >         csrr    a2,vlenb
> > .L3:
> >         vsetvli a5,a0,e32,m1,ta,ma
> >         vle32.v v1,0(a4)
> >         sub     a0,a0,a5
> >         vse32.v v1,0(a3)
> >         add     a4,a4,a2
> >         add     a3,a3,a2
> >         bne     a0,zero,.L3
> > .L1:
> >         ret
> >  
> > gcc/ChangeLog:
> >  
> >         * doc/md.texi: Add WHILE_LEN support.
> >         * internal-fn.cc (while_len_direct): Ditto.
> >         (expand_while_len_optab_fn): Ditto.
> >         (direct_while_len_optab_supported_p): Ditto.
> >         * internal-fn.def (WHILE_LEN): Ditto.
> >         * optabs.def (OPTAB_D): Ditto.
> >         * tree-ssa-loop-manip.cc (create_iv): Ditto.
> >         * tree-ssa-loop-manip.h (create_iv): Ditto.
> >         * tree-vect-loop-manip.cc (vect_set_loop_controls_by_while_len): Ditto.
> >         (vect_set_loop_condition_partial_vectors): Ditto.
> >         * tree-vect-loop.cc (vect_get_loop_len): Ditto.
> >         * tree-vect-stmts.cc (vectorizable_store): Ditto.
> >         (vectorizable_load): Ditto.
> >         * tree-vectorizer.h (vect_get_loop_len): Ditto.
> >  
> > ---
> > gcc/doc/md.texi             |  14 +++
> > gcc/internal-fn.cc          |  29 ++++++
> > gcc/internal-fn.def         |   1 +
> > gcc/optabs.def              |   1 +
> > gcc/tree-ssa-loop-manip.cc  |   4 +-
> > gcc/tree-ssa-loop-manip.h   |   2 +-
> > gcc/tree-vect-loop-manip.cc | 186 ++++++++++++++++++++++++++++++++++--
> > gcc/tree-vect-loop.cc       |  35 +++++--
> > gcc/tree-vect-stmts.cc      |   9 +-
> > gcc/tree-vectorizer.h       |   4 +-
> > 10 files changed, 264 insertions(+), 21 deletions(-)
> >  
> > diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
> > index 8e3113599fd..72178ab014c 100644
> > --- a/gcc/doc/md.texi
> > +++ b/gcc/doc/md.texi
> > @@ -4965,6 +4965,20 @@ for (i = 1; i < operand3; i++)
> >    operand0[i] = operand0[i - 1] && (operand1 + i < operand2);
> > @end smallexample
> > +@cindex @code{while_len@var{m}@var{n}} instruction pattern
> > +@item @code{while_len@var{m}@var{n}}
> > +Set operand 0 to the number of active elements in vector will be updated value.
> > +operand 1 is the total elements need to be updated value.
> > +operand 2 is the vectorization factor.
> > +The operation is equivalent to:
> > +
> > +@smallexample
> > +operand0 = MIN (operand1, operand2);
> > +operand2 can be const_poly_int or poly_int related to vector mode size.
> > +Some target like RISC-V has a standalone instruction to get MIN (n, MODE SIZE) so
> > +that we can reduce a use of general purpose register.
> > +@end smallexample
> > +
> > @cindex @code{check_raw_ptrs@var{m}} instruction pattern
> > @item @samp{check_raw_ptrs@var{m}}
> > Check whether, given two pointers @var{a} and @var{b} and a length @var{len},
> > diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
> > index 6e81dc05e0e..5f44def90d3 100644
> > --- a/gcc/internal-fn.cc
> > +++ b/gcc/internal-fn.cc
> > @@ -127,6 +127,7 @@ init_internal_fns ()
> > #define cond_binary_direct { 1, 1, true }
> > #define cond_ternary_direct { 1, 1, true }
> > #define while_direct { 0, 2, false }
> > +#define while_len_direct { 0, 0, false }
> > #define fold_extract_direct { 2, 2, false }
> > #define fold_left_direct { 1, 1, false }
> > #define mask_fold_left_direct { 1, 1, false }
> > @@ -3702,6 +3703,33 @@ expand_while_optab_fn (internal_fn, gcall *stmt, convert_optab optab)
> >      emit_move_insn (lhs_rtx, ops[0].value);
> > }
> > +/* Expand WHILE_LEN call STMT using optab OPTAB.  */
> > +static void
> > +expand_while_len_optab_fn (internal_fn, gcall *stmt, convert_optab optab)
> > +{
> > +  expand_operand ops[3];
> > +  tree rhs_type[2];
> > +
> > +  tree lhs = gimple_call_lhs (stmt);
> > +  tree lhs_type = TREE_TYPE (lhs);
> > +  rtx lhs_rtx = expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE);
> > +  create_output_operand (&ops[0], lhs_rtx, TYPE_MODE (lhs_type));
> > +
> > +  for (unsigned int i = 0; i < gimple_call_num_args (stmt); ++i)
> > +    {
> > +      tree rhs = gimple_call_arg (stmt, i);
> > +      rhs_type[i] = TREE_TYPE (rhs);
> > +      rtx rhs_rtx = expand_normal (rhs);
> > +      create_input_operand (&ops[i + 1], rhs_rtx, TYPE_MODE (rhs_type[i]));
> > +    }
> > +
> > +  insn_code icode = direct_optab_handler (optab, TYPE_MODE (rhs_type[0]));
> > +
> > +  expand_insn (icode, 3, ops);
> > +  if (!rtx_equal_p (lhs_rtx, ops[0].value))
> > +    emit_move_insn (lhs_rtx, ops[0].value);
> > +}
> > +
> > /* Expand a call to a convert-like optab using the operands in STMT.
> >     FN has a single output operand and NARGS input operands.  */
> > @@ -3843,6 +3871,7 @@ multi_vector_optab_supported_p (convert_optab optab, tree_pair types,
> > #define direct_scatter_store_optab_supported_p convert_optab_supported_p
> > #define direct_len_store_optab_supported_p direct_optab_supported_p
> > #define direct_while_optab_supported_p convert_optab_supported_p
> > +#define direct_while_len_optab_supported_p direct_optab_supported_p
> > #define direct_fold_extract_optab_supported_p direct_optab_supported_p
> > #define direct_fold_left_optab_supported_p direct_optab_supported_p
> > #define direct_mask_fold_left_optab_supported_p direct_optab_supported_p
> > diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
> > index 7fe742c2ae7..3a933abff5d 100644
> > --- a/gcc/internal-fn.def
> > +++ b/gcc/internal-fn.def
> > @@ -153,6 +153,7 @@ DEF_INTERNAL_OPTAB_FN (VEC_SET, 0, vec_set, vec_set)
> > DEF_INTERNAL_OPTAB_FN (LEN_STORE, 0, len_store, len_store)
> > DEF_INTERNAL_OPTAB_FN (WHILE_ULT, ECF_CONST | ECF_NOTHROW, while_ult, while)
> > +DEF_INTERNAL_OPTAB_FN (WHILE_LEN, ECF_CONST | ECF_NOTHROW, while_len, while_len)
> > DEF_INTERNAL_OPTAB_FN (CHECK_RAW_PTRS, ECF_CONST | ECF_NOTHROW,
> >        check_raw_ptrs, check_ptrs)
> > DEF_INTERNAL_OPTAB_FN (CHECK_WAR_PTRS, ECF_CONST | ECF_NOTHROW,
> > diff --git a/gcc/optabs.def b/gcc/optabs.def
> > index 695f5911b30..f5938bd2c24 100644
> > --- a/gcc/optabs.def
> > +++ b/gcc/optabs.def
> > @@ -476,3 +476,4 @@ OPTAB_DC (vec_series_optab, "vec_series$a", VEC_SERIES)
> > OPTAB_D (vec_shl_insert_optab, "vec_shl_insert_$a")
> > OPTAB_D (len_load_optab, "len_load_$a")
> > OPTAB_D (len_store_optab, "len_store_$a")
> > +OPTAB_D (while_len_optab, "while_len$a")
> > diff --git a/gcc/tree-ssa-loop-manip.cc b/gcc/tree-ssa-loop-manip.cc
> > index 09acc1c94cc..cdbf280e249 100644
> > --- a/gcc/tree-ssa-loop-manip.cc
> > +++ b/gcc/tree-ssa-loop-manip.cc
> > @@ -59,14 +59,14 @@ static bitmap_obstack loop_renamer_obstack;
> > void
> > create_iv (tree base, tree step, tree var, class loop *loop,
> >    gimple_stmt_iterator *incr_pos, bool after,
> > -    tree *var_before, tree *var_after)
> > +    tree *var_before, tree *var_after, enum tree_code code)
> > {
> >    gassign *stmt;
> >    gphi *phi;
> >    tree initial, step1;
> >    gimple_seq stmts;
> >    tree vb, va;
> > -  enum tree_code incr_op = PLUS_EXPR;
> > +  enum tree_code incr_op = code;
> >    edge pe = loop_preheader_edge (loop);
> >    if (var != NULL_TREE)
> > diff --git a/gcc/tree-ssa-loop-manip.h b/gcc/tree-ssa-loop-manip.h
> > index d49273a3987..da755320a3a 100644
> > --- a/gcc/tree-ssa-loop-manip.h
> > +++ b/gcc/tree-ssa-loop-manip.h
> > @@ -23,7 +23,7 @@ along with GCC; see the file COPYING3.  If not see
> > typedef void (*transform_callback)(class loop *, void *);
> > extern void create_iv (tree, tree, tree, class loop *, gimple_stmt_iterator *,
> > -        bool, tree *, tree *);
> > +        bool, tree *, tree *, enum tree_code = PLUS_EXPR);
> > extern void rewrite_into_loop_closed_ssa (bitmap, unsigned);
> > extern void verify_loop_closed_ssa (bool, class loop * = NULL);
> > diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
> > index f60fa50e8f4..f3cd6c51d2e 100644
> > --- a/gcc/tree-vect-loop-manip.cc
> > +++ b/gcc/tree-vect-loop-manip.cc
> > @@ -682,6 +682,173 @@ vect_set_loop_controls_directly (class loop *loop, loop_vec_info loop_vinfo,
> >    return next_ctrl;
> > }
> > +/* Helper for vect_set_loop_condition_partial_vectors.  Generate definitions
> > +   for all the rgroup controls in RGC and return a control that is nonzero
> > +   when the loop needs to iterate.  Add any new preheader statements to
> > +   PREHEADER_SEQ.  Use LOOP_COND_GSI to insert code before the exit gcond.
> > +
> > +   RGC belongs to loop LOOP.  The loop originally iterated NITERS
> > +   times and has been vectorized according to LOOP_VINFO.
> > +
> > +   Unlike vect_set_loop_controls_directly which is iterating from 0-based IV
> > +   to TEST_LIMIT - bias.
> > +
> > +   In vect_set_loop_controls_by_while_len, we are iterating from start at
> > +   IV = TEST_LIMIT - bias and keep subtract IV by the length calculated by
> > +   IFN_WHILE_LEN pattern.
> > +
> > +   Note: the cost of the code generated by this function is modeled
> > +   by vect_estimate_min_profitable_iters, so changes here may need
> > +   corresponding changes there.
> > +
> > +   1. Single rgroup, the Gimple IR should be:
> > +
> > + <bb 3>
> > + _19 = (unsigned long) n_5(D);
> > + ...
> > +
> > + <bb 4>:
> > + ...
> > + # ivtmp_20 = PHI <ivtmp_21(4), _19(3)>
> > + ...
> > + _22 = .WHILE_LEN (ivtmp_20, vf);
> > + ...
> > + vector statement (use _22);
> > + ...
> > + ivtmp_21 = ivtmp_20 - _22;
> > + ...
> > + if (ivtmp_21 != 0)
> > +   goto <bb 4>; [75.00%]
> > + else
> > +   goto <bb 5>; [25.00%]
> > +
> > + <bb 5>
> > + return;
> > +
> > +   Note: IFN_WHILE_LEN will guarantee "ivtmp_21 = ivtmp_20 - _22" never
> > +   underflow 0.
> > +
> > +   2. Multiple rgroup, the Gimple IR should be:
> > +
> > + <bb 3>
> > + _70 = (unsigned long) bnd.7_52;
> > + _71 = _70 * 2;
> > + _72 = MAX_EXPR <_71, 4>;
> > + _73 = _72 + 18446744073709551612;
> > + ...
> > +
> > + <bb 4>:
> > + ...
> > + # ivtmp_74 = PHI <ivtmp_75(6), _73(12)>
> > + # ivtmp_77 = PHI <ivtmp_78(6), _71(12)>
> > + _76 = .WHILE_LEN (ivtmp_74, vf * nitems_per_ctrl);
> > + _79 = .WHILE_LEN (ivtmp_77, vf * nitems_per_ctrl);
> > + ...
> > + vector statement (use _79);
> > + ...
> > + vector statement (use _76);
> > + ...
> > + _65 = _79 / 2;
> > + vector statement (use _65);
> > + ...
> > + _68 = _76 / 2;
> > + vector statement (use _68);
> > + ...
> > + ivtmp_78 = ivtmp_77 - _79;
> > + ivtmp_75 = ivtmp_74 - _76;
> > + ...
> > + if (ivtmp_78 != 0)
> > +   goto <bb 4>; [75.00%]
> > + else
> > +   goto <bb 5>; [25.00%]
> > +
> > + <bb 5>
> > + return;
> > +
> > +*/
> > +
> > +static tree
> > +vect_set_loop_controls_by_while_len (class loop *loop, loop_vec_info loop_vinfo,
> > +      gimple_seq *preheader_seq,
> > +      gimple_seq *header_seq,
> > +      rgroup_controls *rgc, tree niters)
> > +{
> > +  tree compare_type = LOOP_VINFO_RGROUP_COMPARE_TYPE (loop_vinfo);
> > +  tree iv_type = LOOP_VINFO_RGROUP_IV_TYPE (loop_vinfo);
> > +  /* We are not allowing masked approach in WHILE_LEN.  */
> > +  gcc_assert (!LOOP_VINFO_FULLY_MASKED_P (loop_vinfo));
> > +
> > +  tree ctrl_type = rgc->type;
> > +  unsigned int nitems_per_iter = rgc->max_nscalars_per_iter * rgc->factor;
> > +  poly_uint64 nitems_per_ctrl = TYPE_VECTOR_SUBPARTS (ctrl_type) * rgc->factor;
> > +  poly_uint64 vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
> > +
> > +  /* Calculate the maximum number of item values that the rgroup
> > +     handles in total, the number that it handles for each iteration
> > +     of the vector loop.  */
> > +  tree nitems_total = niters;
> > +  if (nitems_per_iter != 1)
> > +    {
> > +      /* We checked before setting LOOP_VINFO_USING_PARTIAL_VECTORS_P that
> > + these multiplications don't overflow.  */
> > +      tree compare_factor = build_int_cst (compare_type, nitems_per_iter);
> > +      nitems_total = gimple_build (preheader_seq, MULT_EXPR, compare_type,
> > +    nitems_total, compare_factor);
> > +    }
> > +
> > +  /* Convert the comparison value to the IV type (either a no-op or
> > +     a promotion).  */
> > +  nitems_total = gimple_convert (preheader_seq, iv_type, nitems_total);
> > +
> > +  /* Create an induction variable that counts the number of items
> > +     processed.  */
> > +  tree index_before_incr, index_after_incr;
> > +  gimple_stmt_iterator incr_gsi;
> > +  bool insert_after;
> > +  standard_iv_increment_position (loop, &incr_gsi, &insert_after);
> > +
> > +  /* Test the decremented IV, which will never underflow 0 since we have
> > +     IFN_WHILE_LEN to gurantee that.  */
> > +  tree test_limit = nitems_total;
> > +
> > +  /* Provide a definition of each control in the group.  */
> > +  tree ctrl;
> > +  unsigned int i;
> > +  FOR_EACH_VEC_ELT_REVERSE (rgc->controls, i, ctrl)
> > +    {
> > +      /* Previous controls will cover BIAS items.  This control covers the
> > + next batch.  */
> > +      poly_uint64 bias = nitems_per_ctrl * i;
> > +      tree bias_tree = build_int_cst (iv_type, bias);
> > +
> > +      /* Rather than have a new IV that starts at TEST_LIMIT and goes down to
> > + BIAS, prefer to use the same TEST_LIMIT - BIAS based IV for each
> > + control and adjust the bound down by BIAS.  */
> > +      tree this_test_limit = test_limit;
> > +      if (i != 0)
> > + {
> > +   this_test_limit = gimple_build (preheader_seq, MAX_EXPR, iv_type,
> > +   this_test_limit, bias_tree);
> > +   this_test_limit = gimple_build (preheader_seq, MINUS_EXPR, iv_type,
> > +   this_test_limit, bias_tree);
> > + }
> > +
> > +      /* Create decrement IV.  */
> > +      create_iv (this_test_limit, ctrl, NULL_TREE, loop, &incr_gsi,
> > + insert_after, &index_before_incr, &index_after_incr,
> > + MINUS_EXPR);
> > +
> > +      poly_uint64 final_vf = vf * nitems_per_iter;
> > +      tree vf_step = build_int_cst (iv_type, final_vf);
> > +      tree res_len = gimple_build (header_seq, IFN_WHILE_LEN, iv_type,
> > +    index_before_incr, vf_step);
> > +      gassign *assign = gimple_build_assign (ctrl, res_len);
> > +      gimple_seq_add_stmt (header_seq, assign);
> > +    }
> > +
> > +  return index_after_incr;
> > +}
> > +
> > /* Set up the iteration condition and rgroup controls for LOOP, given
> >     that LOOP_VINFO_USING_PARTIAL_VECTORS_P is true for the vectorized
> >     loop.  LOOP_VINFO describes the vectorization of LOOP.  NITERS is
> > @@ -703,6 +870,7 @@ vect_set_loop_condition_partial_vectors (class loop *loop,
> >    bool use_masks_p = LOOP_VINFO_FULLY_MASKED_P (loop_vinfo);
> >    tree compare_type = LOOP_VINFO_RGROUP_COMPARE_TYPE (loop_vinfo);
> > +  tree iv_type = LOOP_VINFO_RGROUP_IV_TYPE (loop_vinfo);
> >    unsigned int compare_precision = TYPE_PRECISION (compare_type);
> >    tree orig_niters = niters;
> > @@ -757,12 +925,18 @@ vect_set_loop_condition_partial_vectors (class loop *loop,
> > bool might_wrap_p = vect_rgroup_iv_might_wrap_p (loop_vinfo, rgc);
> > /* Set up all controls for this group.  */
> > - test_ctrl = vect_set_loop_controls_directly (loop, loop_vinfo,
> > -      &preheader_seq,
> > -      &header_seq,
> > -      loop_cond_gsi, rgc,
> > -      niters, niters_skip,
> > -      might_wrap_p);
> > + if (direct_internal_fn_supported_p (IFN_WHILE_LEN, iv_type,
> > +     OPTIMIZE_FOR_SPEED))
> > +   test_ctrl
> > +     = vect_set_loop_controls_by_while_len (loop, loop_vinfo,
> > +    &preheader_seq, &header_seq,
> > +    rgc, niters);
> > + else
> > +   test_ctrl
> > +     = vect_set_loop_controls_directly (loop, loop_vinfo, &preheader_seq,
> > +        &header_seq, loop_cond_gsi, rgc,
> > +        niters, niters_skip,
> > +        might_wrap_p);
> >        }
> >    /* Emit all accumulated statements.  */
> > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> > index 1ba9f18d73e..5bffd9a6322 100644
> > --- a/gcc/tree-vect-loop.cc
> > +++ b/gcc/tree-vect-loop.cc
> > @@ -10360,12 +10360,14 @@ vect_record_loop_len (loop_vec_info loop_vinfo, vec_loop_lens *lens,
> >     rgroup that operates on NVECTORS vectors, where 0 <= INDEX < NVECTORS.  */
> > tree
> > -vect_get_loop_len (loop_vec_info loop_vinfo, vec_loop_lens *lens,
> > -    unsigned int nvectors, unsigned int index)
> > +vect_get_loop_len (gimple_stmt_iterator *gsi, loop_vec_info loop_vinfo,
> > +    vec_loop_lens *lens, unsigned int nvectors, tree vectype,
> > +    unsigned int index)
> > {
> >    rgroup_controls *rgl = &(*lens)[nvectors - 1];
> > -  bool use_bias_adjusted_len =
> > -    LOOP_VINFO_PARTIAL_LOAD_STORE_BIAS (loop_vinfo) != 0;
> > +  bool use_bias_adjusted_len
> > +    = LOOP_VINFO_PARTIAL_LOAD_STORE_BIAS (loop_vinfo) != 0;
> > +  tree iv_type = LOOP_VINFO_RGROUP_IV_TYPE (loop_vinfo);
> >    /* Populate the rgroup's len array, if this is the first time we've
> >       used it.  */
> > @@ -10386,8 +10388,8 @@ vect_get_loop_len (loop_vec_info loop_vinfo, vec_loop_lens *lens,
> >   if (use_bias_adjusted_len)
> >     {
> >       gcc_assert (i == 0);
> > -       tree adjusted_len =
> > - make_temp_ssa_name (len_type, NULL, "adjusted_loop_len");
> > +       tree adjusted_len
> > + = make_temp_ssa_name (len_type, NULL, "adjusted_loop_len");
> >       SSA_NAME_DEF_STMT (adjusted_len) = gimple_build_nop ();
> >       rgl->bias_adjusted_ctrl = adjusted_len;
> >     }
> > @@ -10396,6 +10398,27 @@ vect_get_loop_len (loop_vec_info loop_vinfo, vec_loop_lens *lens,
> >    if (use_bias_adjusted_len)
> >      return rgl->bias_adjusted_ctrl;
> > +  else if (direct_internal_fn_supported_p (IFN_WHILE_LEN, iv_type,
> > +    OPTIMIZE_FOR_SPEED))
> > +    {
> > +      tree loop_len = rgl->controls[index];
> > +      poly_int64 nunits1 = TYPE_VECTOR_SUBPARTS (rgl->type);
> > +      poly_int64 nunits2 = TYPE_VECTOR_SUBPARTS (vectype);
> > +      if (maybe_ne (nunits1, nunits2))
> > + {
> > +   /* A loop len for data type X can be reused for data type Y
> > +      if X has N times more elements than Y and if Y's elements
> > +      are N times bigger than X's.  */
> > +   gcc_assert (multiple_p (nunits1, nunits2));
> > +   unsigned int factor = exact_div (nunits1, nunits2).to_constant ();
> > +   gimple_seq seq = NULL;
> > +   loop_len = gimple_build (&seq, RDIV_EXPR, iv_type, loop_len,
> > +    build_int_cst (iv_type, factor));
> > +   if (seq)
> > +     gsi_insert_seq_before (gsi, seq, GSI_SAME_STMT);
> > + }
> > +      return loop_len;
> > +    }
> >    else
> >      return rgl->controls[index];
> > }
> > diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
> > index efa2d0daa52..708c8a1d806 100644
> > --- a/gcc/tree-vect-stmts.cc
> > +++ b/gcc/tree-vect-stmts.cc
> > @@ -8653,8 +8653,9 @@ vectorizable_store (vec_info *vinfo,
> >       else if (loop_lens)
> > {
> >   tree final_len
> > -     = vect_get_loop_len (loop_vinfo, loop_lens,
> > - vec_num * ncopies, vec_num * j + i);
> > +     = vect_get_loop_len (gsi, loop_vinfo, loop_lens,
> > + vec_num * ncopies, vectype,
> > + vec_num * j + i);
> >   tree ptr = build_int_cst (ref_type, align * BITS_PER_UNIT);
> >   machine_mode vmode = TYPE_MODE (vectype);
> >   opt_machine_mode new_ovmode
> > @@ -10009,8 +10010,8 @@ vectorizable_load (vec_info *vinfo,
> >     else if (loop_lens && memory_access_type != VMAT_INVARIANT)
> >       {
> > tree final_len
> > -   = vect_get_loop_len (loop_vinfo, loop_lens,
> > -        vec_num * ncopies,
> > +   = vect_get_loop_len (gsi, loop_vinfo, loop_lens,
> > +        vec_num * ncopies, vectype,
> >        vec_num * j + i);
> > tree ptr = build_int_cst (ref_type,
> >   align * BITS_PER_UNIT);
> > diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
> > index 9cf2fb23fe3..e5cf38caf4b 100644
> > --- a/gcc/tree-vectorizer.h
> > +++ b/gcc/tree-vectorizer.h
> > @@ -2293,8 +2293,8 @@ extern tree vect_get_loop_mask (gimple_stmt_iterator *, vec_loop_masks *,
> > unsigned int, tree, unsigned int);
> > extern void vect_record_loop_len (loop_vec_info, vec_loop_lens *, unsigned int,
> >   tree, unsigned int);
> > -extern tree vect_get_loop_len (loop_vec_info, vec_loop_lens *, unsigned int,
> > -        unsigned int);
> > +extern tree vect_get_loop_len (gimple_stmt_iterator *, loop_vec_info,
> > +        vec_loop_lens *, unsigned int, tree, unsigned int);
> > extern gimple_seq vect_gen_len (tree, tree, tree, tree);
> > extern stmt_vec_info info_for_reduction (vec_info *, stmt_vec_info);
> > extern bool reduction_fn_for_scalar_code (code_helper, internal_fn *);
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)