On Thu, Oct 19, 2017 at 12:28 AM, Richard Sandiford
<richard.sandif...@linaro.org> wrote:
> Richard Biener <richard.guent...@gmail.com> writes:
>> On Fri, Oct 13, 2017 at 4:10 PM, Richard Sandiford
>> <richard.sandif...@linaro.org> wrote:
>>> Normally we adjust the vector loop so that it iterates:
>>>
>>> (original number of scalar iterations - number of peels) / VF
>>>
>>> times, enforcing this using an IV that starts at zero and increments
>>> by one each iteration. However, dividing by VF would be expensive
>>> for variable VF, so this patch adds an alternative in which the IV
>>> increments by VF each iteration instead. We then need to take care
>>> to handle possible overflow in the IV.
>>
>> Hmm, why do you need to handle possible overflow? Doesn't the
>> original loop have a natural IV that evolves like this? After all we
>> can compute an expression for niters of the scalar loop.
>
> The problem comes with loops like:
>
> unsigned char i = 0;
> do
> {
> ...
> i--;
> }
> while (i != 0);
>
> The loop statements execute 256 times and the latch executes 255 times.
> LOOP_VINFO_NITERSM1 is then 255 but LOOP_VINFO_NITERS (stored as an
> unsigned char) is 0.
Yes, that's an existing issue and the reason why I introduced
NITERSM1. All remaining uses of NITERS should really go away
because of this corner-case. So you are introducing a new user?
Richard.
> This leads to things like:
>
> /* Constant case. */
> if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
> {
> tree cst_niters = LOOP_VINFO_NITERS (loop_vinfo);
> tree cst_nitersm1 = LOOP_VINFO_NITERSM1 (loop_vinfo);
>
> gcc_assert (TREE_CODE (cst_niters) == INTEGER_CST);
> gcc_assert (TREE_CODE (cst_nitersm1) == INTEGER_CST);
> if (wi::to_widest (cst_nitersm1) < wi::to_widest (cst_niters))
> return true;
> }
>
> in loop_niters_no_overflow.
>
>>> The new mechanism isn't used yet; a later patch replaces the
>>> "if (1)" with a check for variable VF. If the patch is OK, I'll
>>> hold off applying it until the follow-on is ready to go in.
>>
>> I indeed don't like code that isn't exercised. Otherwise looks reasonable.
>
> Thanks.
>
> Richard
>
>> Thanks,
>> Richard.
>>
>>> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64-linux-gnu.
>>> OK to install when the time comes?
>>>
>>> Richard
>>>
>>>
>>> 2017-10-13 Richard Sandiford <richard.sandif...@linaro.org>
>>>
>>> gcc/
>>> * tree-vect-loop-manip.c: Include gimple-fold.h.
>>> (slpeel_make_loop_iterate_ntimes): Add step, final_iv and
>>> niters_maybe_zero parameters. Handle other cases besides a step of
>>> 1.
>>> (vect_gen_vector_loop_niters): Add a step_vector_ptr parameter.
>>> Add a path that uses a step of VF instead of 1, but disable it
>>> for now.
>>> (vect_do_peeling): Add step_vector, niters_vector_mult_vf_var
>>> and niters_no_overflow parameters. Update calls to
>>> slpeel_make_loop_iterate_ntimes and vect_gen_vector_loop_niters.
>>> Create a new SSA name if the latter choses to use a ste other
>>> than zero, and return it via niters_vector_mult_vf_var.
>>> * tree-vect-loop.c (vect_transform_loop): Update calls to
>>> vect_do_peeling, vect_gen_vector_loop_niters and
>>> slpeel_make_loop_iterate_ntimes.
>>> * tree-vectorizer.h (slpeel_make_loop_iterate_ntimes,
>>> vect_do_peeling)
>>> (vect_gen_vector_loop_niters): Update declarations after above
>> changes.
>>>
>>> Index: gcc/tree-vect-loop-manip.c
>>> ===================================================================
>>> --- gcc/tree-vect-loop-manip.c 2017-10-13 15:01:40.144777367 +0100
>>> +++ gcc/tree-vect-loop-manip.c 2017-10-13 15:01:40.296014347 +0100
>>> @@ -41,6 +41,7 @@ Software Foundation; either version 3, o
>>> #include "tree-scalar-evolution.h"
>>> #include "tree-vectorizer.h"
>>> #include "tree-ssa-loop-ivopts.h"
>>> +#include "gimple-fold.h"
>>>
>>> /*************************************************************************
>>> Simple Loop Peeling Utilities
>>> @@ -247,30 +248,115 @@ adjust_phi_and_debug_stmts (gimple *upda
>>> gimple_bb (update_phi));
>>> }
>>>
>>> -/* Make the LOOP iterate NITERS times. This is done by adding a new IV
>>> - that starts at zero, increases by one and its limit is NITERS.
>>> +/* Make LOOP iterate N == (NITERS - STEP) / STEP + 1 times,
>>> + where NITERS is known to be outside the range [1, STEP - 1].
>>> + This is equivalent to making the loop execute NITERS / STEP
>>> + times when NITERS is nonzero and (1 << M) / STEP times otherwise,
>>> + where M is the precision of NITERS.
>>> +
>>> + NITERS_MAYBE_ZERO is true if NITERS can be zero, false it is known
>>> + to be >= STEP. In the latter case N is always NITERS / STEP.
>>> +
>>> + If FINAL_IV is nonnull, it is an SSA name that should be set to
>>> + N * STEP on exit from the loop.
>>>
>>> Assumption: the exit-condition of LOOP is the last stmt in the loop. */
>>>
>>> void
>>> -slpeel_make_loop_iterate_ntimes (struct loop *loop, tree niters)
>>> +slpeel_make_loop_iterate_ntimes (struct loop *loop, tree niters, tree step,
>>> + tree final_iv, bool niters_maybe_zero)
>>> {
>>> tree indx_before_incr, indx_after_incr;
>>> gcond *cond_stmt;
>>> gcond *orig_cond;
>>> + edge pe = loop_preheader_edge (loop);
>>> edge exit_edge = single_exit (loop);
>>> gimple_stmt_iterator loop_cond_gsi;
>>> gimple_stmt_iterator incr_gsi;
>>> bool insert_after;
>>> - tree init = build_int_cst (TREE_TYPE (niters), 0);
>>> - tree step = build_int_cst (TREE_TYPE (niters), 1);
>>> source_location loop_loc;
>>> enum tree_code code;
>>> + tree niters_type = TREE_TYPE (niters);
>>>
>>> orig_cond = get_loop_exit_condition (loop);
>>> gcc_assert (orig_cond);
>>> loop_cond_gsi = gsi_for_stmt (orig_cond);
>>>
>>> + tree init, limit;
>>> + if (!niters_maybe_zero && integer_onep (step))
>>> + {
>>> + /* In this case we can use a simple 0-based IV:
>>> +
>>> + A:
>>> + x = 0;
>>> + do
>>> + {
>>> + ...
>>> + x += 1;
>>> + }
>>> + while (x < NITERS); */
>>> + code = (exit_edge->flags & EDGE_TRUE_VALUE) ? GE_EXPR : LT_EXPR;
>>> + init = build_zero_cst (niters_type);
>>> + limit = niters;
>>> + }
>>> + else
>>> + {
>>> + /* The following works for all values of NITERS except 0:
>>> +
>>> + B:
>>> + x = 0;
>>> + do
>>> + {
>>> + ...
>>> + x += STEP;
>>> + }
>>> + while (x <= NITERS - STEP);
>>> +
>>> + so that the loop continues to iterate if x + STEP - 1 < NITERS
>>> + but stops if x + STEP - 1 >= NITERS.
>>> +
>>> + However, if NITERS is zero, x never hits a value above NITERS -
>>> STEP
>>> + before wrapping around. There are two obvious ways of dealing with
>>> + this:
>>> +
>>> + - start at STEP - 1 and compare x before incrementing it
>>> + - start at -1 and compare x after incrementing it
>>> +
>>> + The latter is simpler and is what we use. The loop in this case
>>> + looks like:
>>> +
>>> + C:
>>> + x = -1;
>>> + do
>>> + {
>>> + ...
>>> + x += STEP;
>>> + }
>>> + while (x < NITERS - STEP);
>>> +
>>> + In both cases the loop limit is NITERS - STEP. */
>>> + gimple_seq seq = NULL;
>>> + limit = force_gimple_operand (niters, &seq, true, NULL_TREE);
>>> + limit = gimple_build (&seq, MINUS_EXPR, TREE_TYPE (limit), limit,
>> step);
>>> + if (seq)
>>> + {
>>> + basic_block new_bb = gsi_insert_seq_on_edge_immediate (pe, seq);
>>> + gcc_assert (!new_bb);
>>> + }
>>> + if (niters_maybe_zero)
>>> + {
>>> + /* Case C. */
>>> + code = (exit_edge->flags & EDGE_TRUE_VALUE) ? GE_EXPR : LT_EXPR;
>>> + init = build_all_ones_cst (niters_type);
>>> + }
>>> + else
>>> + {
>>> + /* Case B. */
>>> + code = (exit_edge->flags & EDGE_TRUE_VALUE) ? GT_EXPR : LE_EXPR;
>>> + init = build_zero_cst (niters_type);
>>> + }
>>> + }
>>> +
>>> standard_iv_increment_position (loop, &incr_gsi, &insert_after);
>>> create_iv (init, step, NULL_TREE, loop,
>>> &incr_gsi, insert_after, &indx_before_incr, &indx_after_incr);
>>> @@ -278,11 +364,10 @@ slpeel_make_loop_iterate_ntimes (struct
>>> indx_after_incr = force_gimple_operand_gsi (&loop_cond_gsi,
>> indx_after_incr,
>>> true, NULL_TREE, true,
>>> GSI_SAME_STMT);
>>> - niters = force_gimple_operand_gsi (&loop_cond_gsi, niters, true,
>>> NULL_TREE,
>>> + limit = force_gimple_operand_gsi (&loop_cond_gsi, limit, true, NULL_TREE,
>>> true, GSI_SAME_STMT);
>>>
>>> - code = (exit_edge->flags & EDGE_TRUE_VALUE) ? GE_EXPR : LT_EXPR;
>>> - cond_stmt = gimple_build_cond (code, indx_after_incr, niters, NULL_TREE,
>>> + cond_stmt = gimple_build_cond (code, indx_after_incr, limit, NULL_TREE,
>>> NULL_TREE);
>>>
>>> gsi_insert_before (&loop_cond_gsi, cond_stmt, GSI_SAME_STMT);
>>> @@ -301,8 +386,23 @@ slpeel_make_loop_iterate_ntimes (struct
>>> }
>>>
>>> /* Record the number of latch iterations. */
>>> - loop->nb_iterations = fold_build2 (MINUS_EXPR, TREE_TYPE (niters),
>>> niters,
>>> - build_int_cst (TREE_TYPE (niters), 1));
>>> + if (limit == niters)
>>> + /* Case A: the loop iterates NITERS times. Subtract one to get the
>>> + latch count. */
>>> + loop->nb_iterations = fold_build2 (MINUS_EXPR, niters_type, niters,
>>> + build_int_cst (niters_type, 1));
>>> + else
>>> + /* Case B or C: the loop iterates (NITERS - STEP) / STEP + 1 times.
>>> + Subtract one from this to get the latch count. */
>>> + loop->nb_iterations = fold_build2 (TRUNC_DIV_EXPR, niters_type,
>>> + limit, step);
>>> +
>>> + if (final_iv)
>>> + {
>>> + gassign *assign = gimple_build_assign (final_iv, MINUS_EXPR,
>>> + indx_after_incr, init);
>>> + gsi_insert_on_edge_immediate (single_exit (loop), assign);
>>> + }
>>> }
>>>
>>> /* Helper routine of slpeel_tree_duplicate_loop_to_edge_cfg.
>>> @@ -1170,23 +1270,32 @@ vect_gen_scalar_loop_niters (tree niters
>>> return niters;
>>> }
>>>
>>> -/* This function generates the following statements:
>>> +/* NITERS is the number of times that the original scalar loop executes
>>> + after peeling. Work out the maximum number of iterations N that can
>>> + be handled by the vectorized form of the loop and then either:
>>> +
>>> + a) set *STEP_VECTOR_PTR to the vectorization factor and generate:
>>> +
>>> + niters_vector = N
>>> +
>>> + b) set *STEP_VECTOR_PTR to one and generate:
>>>
>>> - niters = number of iterations loop executes (after peeling)
>>> - niters_vector = niters / vf
>>> + niters_vector = N / vf
>>>
>>> - and places them on the loop preheader edge. NITERS_NO_OVERFLOW is
>>> - true if NITERS doesn't overflow. */
>>> + In both cases, store niters_vector in *NITERS_VECTOR_PTR and add
>>> + any new statements on the loop preheader edge. NITERS_NO_OVERFLOW
>>> + is true if NITERS doesn't overflow (i.e. if NITERS is always nonzero).
>>> */
>>>
>>> void
>>> vect_gen_vector_loop_niters (loop_vec_info loop_vinfo, tree niters,
>>> - tree *niters_vector_ptr, bool
>>> niters_no_overflow)
>>> + tree *niters_vector_ptr, tree *step_vector_ptr,
>>> + bool niters_no_overflow)
>>> {
>>> tree ni_minus_gap, var;
>>> - tree niters_vector, type = TREE_TYPE (niters);
>>> + tree niters_vector, step_vector, type = TREE_TYPE (niters);
>>> int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
>>> edge pe = loop_preheader_edge (LOOP_VINFO_LOOP (loop_vinfo));
>>> - tree log_vf = build_int_cst (type, exact_log2 (vf));
>>> + tree log_vf = NULL_TREE;
>>>
>>> /* If epilogue loop is required because of data accesses with gaps, we
>>> subtract one iteration from the total number of iterations here for
>>> @@ -1207,21 +1316,32 @@ vect_gen_vector_loop_niters (loop_vec_in
>>> else
>>> ni_minus_gap = niters;
>>>
>>> - /* Create: niters >> log2(vf) */
>>> - /* If it's known that niters == number of latch executions + 1 doesn't
>>> - overflow, we can generate niters >> log2(vf); otherwise we generate
>>> - (niters - vf) >> log2(vf) + 1 by using the fact that we know ratio
>>> - will be at least one. */
>>> - if (niters_no_overflow)
>>> - niters_vector = fold_build2 (RSHIFT_EXPR, type, ni_minus_gap, log_vf);
>>> + if (1)
>>> + {
>>> + /* Create: niters >> log2(vf) */
>>> + /* If it's known that niters == number of latch executions + 1
>>> doesn't
>>> + overflow, we can generate niters >> log2(vf); otherwise we generate
>>> + (niters - vf) >> log2(vf) + 1 by using the fact that we know ratio
>>> + will be at least one. */
>>> + log_vf = build_int_cst (type, exact_log2 (vf));
>>> + if (niters_no_overflow)
>>> + niters_vector = fold_build2 (RSHIFT_EXPR, type, ni_minus_gap,
>>> log_vf);
>>> + else
>>> + niters_vector
>>> + = fold_build2 (PLUS_EXPR, type,
>>> + fold_build2 (RSHIFT_EXPR, type,
>>> + fold_build2 (MINUS_EXPR, type,
>>> + ni_minus_gap,
>>> + build_int_cst (type,
>>> vf)),
>>> + log_vf),
>>> + build_int_cst (type, 1));
>>> + step_vector = build_one_cst (type);
>>> + }
>>> else
>>> - niters_vector
>>> - = fold_build2 (PLUS_EXPR, type,
>>> - fold_build2 (RSHIFT_EXPR, type,
>>> - fold_build2 (MINUS_EXPR, type,
>>> ni_minus_gap,
>>> - build_int_cst (type, vf)),
>>> - log_vf),
>>> - build_int_cst (type, 1));
>>> + {
>>> + niters_vector = ni_minus_gap;
>>> + step_vector = build_int_cst (type, vf);
>>> + }
>>>
>>> if (!is_gimple_val (niters_vector))
>>> {
>>> @@ -1231,7 +1351,7 @@ vect_gen_vector_loop_niters (loop_vec_in
>>> gsi_insert_seq_on_edge_immediate (pe, stmts);
>>> /* Peeling algorithm guarantees that vector loop bound is at least
>>> ONE,
>>> we set range information to make niters analyzer's life easier. */
>>> - if (stmts != NULL)
>>> + if (stmts != NULL && log_vf)
>>> set_range_info (niters_vector, VR_RANGE,
>>> wi::to_wide (build_int_cst (type, 1)),
>>> wi::to_wide (fold_build2 (RSHIFT_EXPR, type,
>>> @@ -1239,6 +1359,7 @@ vect_gen_vector_loop_niters (loop_vec_in
>>> log_vf)));
>>> }
>>> *niters_vector_ptr = niters_vector;
>>> + *step_vector_ptr = step_vector;
>>>
>>> return;
>>> }
>>> @@ -1600,7 +1721,12 @@ slpeel_update_phi_nodes_for_lcssa (struc
>>> - TH, CHECK_PROFITABILITY: Threshold of niters to vectorize loop if
>>> CHECK_PROFITABILITY is true.
>>> Output:
>>> - - NITERS_VECTOR: The number of iterations of loop after vectorization.
>>> + - *NITERS_VECTOR and *STEP_VECTOR describe how the main loop should
>>> + iterate after vectorization; see slpeel_make_loop_iterate_ntimes
>>> + for details.
>>> + - *NITERS_VECTOR_MULT_VF_VAR is either null or an SSA name that
>>> + should be set to the number of scalar iterations handled by the
>>> + vector loop. The SSA name is only used on exit from the loop.
>>>
>>> This function peels prolog and epilog from the loop, adds guards
>>> skipping
>>> PROLOG and EPILOG for various conditions. As a result, the changed CFG
>>> @@ -1657,8 +1783,9 @@ slpeel_update_phi_nodes_for_lcssa (struc
>>>
>>> struct loop *
>>> vect_do_peeling (loop_vec_info loop_vinfo, tree niters, tree nitersm1,
>>> - tree *niters_vector, int th, bool check_profitability,
>>> - bool niters_no_overflow)
>>> + tree *niters_vector, tree *step_vector,
>>> + tree *niters_vector_mult_vf_var, int th,
>>> + bool check_profitability, bool niters_no_overflow)
>>> {
>>> edge e, guard_e;
>>> tree type = TREE_TYPE (niters), guard_cond;
>>> @@ -1754,7 +1881,9 @@ vect_do_peeling (loop_vec_info loop_vinf
>>> /* Generate and update the number of iterations for prolog loop. */
>>> niters_prolog = vect_gen_prolog_loop_niters (loop_vinfo, anchor,
>>> &bound_prolog);
>>> - slpeel_make_loop_iterate_ntimes (prolog, niters_prolog);
>>> + tree step_prolog = build_one_cst (TREE_TYPE (niters_prolog));
>>> + slpeel_make_loop_iterate_ntimes (prolog, niters_prolog, step_prolog,
>>> + NULL_TREE, false);
>>>
>>> /* Skip the prolog loop. */
>>> if (skip_prolog)
>>> @@ -1867,9 +1996,20 @@ vect_do_peeling (loop_vec_info loop_vinf
>>> overflows. */
>>> niters_no_overflow |= (prolog_peeling > 0);
>>> vect_gen_vector_loop_niters (loop_vinfo, niters,
>>> - niters_vector, niters_no_overflow);
>>> - vect_gen_vector_loop_niters_mult_vf (loop_vinfo, *niters_vector,
>>> - &niters_vector_mult_vf);
>>> + niters_vector, step_vector,
>>> + niters_no_overflow);
>>> + if (!integer_onep (*step_vector))
>>> + {
>>> + /* On exit from the loop we will have an easy way of calcalating
>>> + NITERS_VECTOR / STEP * STEP. Install a dummy definition
>>> + until then. */
>>> + niters_vector_mult_vf = make_ssa_name (TREE_TYPE
>>> (*niters_vector));
>>> + SSA_NAME_DEF_STMT (niters_vector_mult_vf) = gimple_build_nop ();
>>> + *niters_vector_mult_vf_var = niters_vector_mult_vf;
>>> + }
>>> + else
>>> + vect_gen_vector_loop_niters_mult_vf (loop_vinfo, *niters_vector,
>>> + &niters_vector_mult_vf);
>>> /* Update IVs of original loop as if they were advanced by
>>> niters_vector_mult_vf steps. */
>>> gcc_checking_assert (vect_can_advance_ivs_p (loop_vinfo));
>>> Index: gcc/tree-vect-loop.c
>>> ===================================================================
>>> --- gcc/tree-vect-loop.c 2017-10-13 15:01:40.144777367 +0100
>>> +++ gcc/tree-vect-loop.c 2017-10-13 15:01:40.296014347 +0100
>>> @@ -7273,7 +7273,9 @@ vect_transform_loop (loop_vec_info loop_
>>> basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
>>> int nbbs = loop->num_nodes;
>>> int i;
>>> - tree niters_vector = NULL;
>>> + tree niters_vector = NULL_TREE;
>>> + tree step_vector = NULL_TREE;
>>> + tree niters_vector_mult_vf = NULL_TREE;
>>> int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
>>> bool grouped_store;
>>> bool slp_scheduled = false;
>>> @@ -7342,17 +7344,21 @@ vect_transform_loop (loop_vec_info loop_
>>> LOOP_VINFO_NITERS_UNCHANGED (loop_vinfo) = niters;
>>> tree nitersm1 = unshare_expr (LOOP_VINFO_NITERSM1 (loop_vinfo));
>>> bool niters_no_overflow = loop_niters_no_overflow (loop_vinfo);
>>> - epilogue = vect_do_peeling (loop_vinfo, niters, nitersm1,
>> &niters_vector, th,
>>> + epilogue = vect_do_peeling (loop_vinfo, niters, nitersm1, &niters_vector,
>>> + &step_vector, &niters_vector_mult_vf, th,
>>> check_profitability, niters_no_overflow);
>>> if (niters_vector == NULL_TREE)
>>> {
>>> if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
>>> - niters_vector
>>> - = build_int_cst (TREE_TYPE (LOOP_VINFO_NITERS (loop_vinfo)),
>>> - LOOP_VINFO_INT_NITERS (loop_vinfo) / vf);
>>> + {
>>> + niters_vector
>>> + = build_int_cst (TREE_TYPE (LOOP_VINFO_NITERS (loop_vinfo)),
>>> + LOOP_VINFO_INT_NITERS (loop_vinfo) / vf);
>>> + step_vector = build_one_cst (TREE_TYPE (niters));
>>> + }
>>> else
>>> vect_gen_vector_loop_niters (loop_vinfo, niters, &niters_vector,
>>> - niters_no_overflow);
>>> + &step_vector, niters_no_overflow);
>>> }
>>>
>>> /* 1) Make sure the loop header has exactly two entries
>>> @@ -7603,7 +7609,13 @@ vect_transform_loop (loop_vec_info loop_
>>> } /* stmts in BB */
>>> } /* BBs in loop */
>>>
>>> - slpeel_make_loop_iterate_ntimes (loop, niters_vector);
>>> + /* The vectorization factor is always > 1, so if we use an IV
>> increment of 1.
>>> + a zero NITERS becomes a nonzero NITERS_VECTOR. */
>>> + if (integer_onep (step_vector))
>>> + niters_no_overflow = true;
>>> + slpeel_make_loop_iterate_ntimes (loop, niters_vector, step_vector,
>>> + niters_vector_mult_vf,
>>> + !niters_no_overflow);
>>>
>>> scale_profile_for_vect_loop (loop, vf);
>>>
>>> Index: gcc/tree-vectorizer.h
>>> ===================================================================
>>> --- gcc/tree-vectorizer.h 2017-10-13 15:01:40.144777367 +0100
>>> +++ gcc/tree-vectorizer.h 2017-10-13 15:01:40.296014347 +0100
>>> @@ -1138,13 +1138,14 @@ vect_get_scalar_dr_size (struct data_ref
>>>
>>> /* Simple loop peeling and versioning utilities for vectorizer's purposes -
>>> in tree-vect-loop-manip.c. */
>>> -extern void slpeel_make_loop_iterate_ntimes (struct loop *, tree);
>>> +extern void slpeel_make_loop_iterate_ntimes (struct loop *, tree, tree,
>>> + tree, bool);
>>> extern bool slpeel_can_duplicate_loop_p (const struct loop *, const_edge);
>>> struct loop *slpeel_tree_duplicate_loop_to_edge_cfg (struct loop *,
>>> struct loop *, edge);
>>> extern void vect_loop_versioning (loop_vec_info, unsigned int, bool);
>>> extern struct loop *vect_do_peeling (loop_vec_info, tree, tree,
>>> - tree *, int, bool, bool);
>>> + tree *, tree *, tree *, int, bool,
>>> bool);
>>> extern source_location find_loop_location (struct loop *);
>>> extern bool vect_can_advance_ivs_p (loop_vec_info);
>>>
>>> @@ -1258,7 +1259,8 @@ extern gimple *vect_force_simple_reducti
>>> /* Drive for loop analysis stage. */
>>> extern loop_vec_info vect_analyze_loop (struct loop *, loop_vec_info);
>>> extern tree vect_build_loop_niters (loop_vec_info, bool * = NULL);
>>> -extern void vect_gen_vector_loop_niters (loop_vec_info, tree, tree *,
>>> bool);
>>> +extern void vect_gen_vector_loop_niters (loop_vec_info, tree, tree *,
>>> + tree *, bool);
>>> /* Drive for loop transformation stage. */
>>> extern struct loop *vect_transform_loop (loop_vec_info);
>>> extern loop_vec_info vect_analyze_loop_form (struct loop *);
