On Thu, 27 Aug 2026, Pengfei Li wrote:

> In the current loop vectorizer, negative-step contiguous DRs are
> vectorized with VMAT_CONTIGUOUS_REVERSE, which normally requires
> generating reverse permutations for the loaded or stored vectors.
> However, if all DRs in a connected SLP subgraph use the same lane
> layout, the reverse permutations can be potentially elided.
> 
> This patch adds an elide_rev_perms_p flag to the leader instance of each
> connected SLP subgraph. During SLP graph optimization, we identify SLP
> subgraphs in which reverse permutations might be elided and set the flag
> on the leader instance.
> 
> Since the final VMAT is only known during vectorizable_{load|store}, we
> may still clear the flag if an access is not VMAT_CONTIGUOUS_REVERSE.
> Reverse permutation generation is omitted for DRs with the flag set in
> the end.
> 
> For now, this optimization is conservatively limited to SLP instances of
> slp_inst_kind_store. Support for reduction loops could be added in the
> future.
> 
> This patch is bootstrapped and regression-tested on x86_64-linux-gnu,
> arm-linux-gnueabihf and aarch64-linux-gnu with bootstrap-O3.
> 
> gcc/ChangeLog:
> 
>       * tree-vect-slp.cc (vect_build_slp_instance): Initialize
>       elide_rev_perms_p.
>       (vect_analyze_slp_reduc_chain): Likewise.
>       (vect_analyze_slp_reduction): Likewise.
>       (vect_analyze_slp_reduction_group): Likewise.
>       (vect_analyze_slp_instance): Likewise.
>       (vect_can_elide_rev_perms_p): New helper function.
>       (vect_analyze_rev_perms_elision): New function.
>       (vect_optimize_slp): Call vect_analyze_rev_perms_elision.
>       * tree-vect-stmts.cc (vectorizable_store): Add a SLP instance
>       parameter and handle reverse permutation elision.
>       (vectorizable_load): Likewise.
>       (vect_analyze_stmt): Pass to SLP instance to vectorizable_load
>       and vectorizable_store.
>       (vect_transform_stmt): Likewise.
>       * tree-vectorizer.h: (_slp_instance::elide_rev_perms_p): New
>       member.
> 
> gcc/testsuite/ChangeLog:
> 
>       * gcc.dg/vect/vect-elide-rev-perms-1.c: New test.
>       * gcc.dg/vect/vect-elide-rev-perms-2.c: New test.
>       * gcc.dg/vect/vect-elide-rev-perms-3.c: New test.
>       * gcc.dg/vect/vect-elide-rev-perms-4.c: New test.
>       * gcc.dg/vect/vect-elide-rev-perms-5.c: New test.
> ---
>  .../gcc.dg/vect/vect-elide-rev-perms-1.c      |  34 ++++++
>  .../gcc.dg/vect/vect-elide-rev-perms-2.c      |  39 +++++++
>  .../gcc.dg/vect/vect-elide-rev-perms-3.c      |  38 +++++++
>  .../gcc.dg/vect/vect-elide-rev-perms-4.c      |  38 +++++++
>  .../gcc.dg/vect/vect-elide-rev-perms-5.c      |  42 ++++++++
>  gcc/tree-vect-slp.cc                          | 100 ++++++++++++++++++
>  gcc/tree-vect-stmts.cc                        |  70 ++++++++++--
>  gcc/tree-vectorizer.h                         |   4 +
>  8 files changed, 357 insertions(+), 8 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-1.c
>  create mode 100644 gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-2.c
>  create mode 100644 gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-3.c
>  create mode 100644 gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-4.c
>  create mode 100644 gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-5.c
> 
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-1.c 
> b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-1.c
> new file mode 100644
> index 00000000000..c4c9f6773d8
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-1.c
> @@ -0,0 +1,34 @@
> +/* { dg-require-effective-target vect_int } */
> +/* { dg-options "-O2 -ftree-vectorize -fdump-tree-vect-details" } */
> +
> +#include "tree-vect.h"
> +
> +__attribute__((noipa))
> +void
> +foo (int *a)
> +{
> +  for (int i = 99; i >= 0; i--)
> +    a[i] *= 2;
> +}
> +
> +int
> +main ()
> +{
> +  check_vect ();
> +
> +  int a[100];
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    a[i] = i + 1;
> +
> +  foo (a);
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    if (a[i] != 2 * (i + 1))
> +      __builtin_abort ();
> +}
> +
> +/* { dg-final { scan-tree-dump "Eliding reverse permutation for load" "vect" 
> } } */
> +/* { dg-final { scan-tree-dump "Eliding reverse permutation for store" 
> "vect" } } */
> \ No newline at end of file
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-2.c 
> b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-2.c
> new file mode 100644
> index 00000000000..37ad890cba2
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-2.c
> @@ -0,0 +1,39 @@
> +/* { dg-require-effective-target vect_int } */
> +/* { dg-options "-O2 -ftree-vectorize -fdump-tree-vect-details" } */
> +
> +#include "tree-vect.h"
> +
> +__attribute__((noipa))
> +void
> +foo (int *restrict a, int *restrict b, int *restrict c)
> +{
> +  for (int i = 99; i >= 0; i--)
> +    {
> +      b[i] = a[i] - 1;
> +      c[i] = a[i] + 2;
> +    }
> +}
> +
> +int
> +main ()
> +{
> +  check_vect ();
> +
> +  int a[100];
> +  int b[100];
> +  int c[100];
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    a[i] = i;
> +
> +  foo (a, b, c);
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    if (b[i] != i - 1 || c[i] != i + 2)
> +      __builtin_abort ();
> +}
> +
> +/* { dg-final { scan-tree-dump "Eliding reverse permutation for load" "vect" 
> } } */
> +/* { dg-final { scan-tree-dump "Eliding reverse permutation for store" 
> "vect" } } */
> \ No newline at end of file
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-3.c 
> b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-3.c
> new file mode 100644
> index 00000000000..e1afb6fd9c4
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-3.c
> @@ -0,0 +1,38 @@
> +/* { dg-require-effective-target vect_int } */
> +/* { dg-options "-O2 -ftree-vectorize -fdump-tree-vect-details" } */
> +
> +#include "tree-vect.h"
> +
> +__attribute__((noipa))
> +void
> +foo (int *restrict a, signed char *restrict b)
> +{
> +  for (int i = 99; i >= 0; i--)
> +    a[i] += b[i];
> +}
> +
> +int
> +main ()
> +{
> +  check_vect ();
> +
> +  int a[100];
> +  signed char b[100];
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    {
> +      a[i] = i + 1;
> +      b[i] = i - 1;
> +    }
> +
> +  foo (a, b);
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    if (a[i] != 2 * i)
> +      __builtin_abort ();
> +}
> +
> +/* { dg-final { scan-tree-dump-not "Eliding reverse permutation for load" 
> "vect" } } */
> +/* { dg-final { scan-tree-dump-not "Eliding reverse permutation for store" 
> "vect" } } */
> \ No newline at end of file
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-4.c 
> b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-4.c
> new file mode 100644
> index 00000000000..33e3300a190
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-4.c
> @@ -0,0 +1,38 @@
> +/* { dg-require-effective-target vect_int } */
> +/* { dg-options "-O2 -ftree-vectorize -fdump-tree-vect-details" } */
> +
> +#include "tree-vect.h"
> +
> +__attribute__((noipa))
> +void
> +foo (int *restrict a, int *restrict b)
> +{
> +  for (int i = 99; i >= 0; i--)
> +    a[i] += b[99 - i];
> +}
> +
> +int
> +main ()
> +{
> +  check_vect ();
> +
> +  int a[100];
> +  int b[100];
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    {
> +      a[i] = i;
> +      b[i] = i;
> +    }
> +
> +  foo (a, b);
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    if (a[i] != 99)
> +      __builtin_abort ();
> +}
> +
> +/* { dg-final { scan-tree-dump-not "Eliding reverse permutation for load" 
> "vect" } } */
> +/* { dg-final { scan-tree-dump-not "Eliding reverse permutation for store" 
> "vect" } } */
> \ No newline at end of file
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-5.c 
> b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-5.c
> new file mode 100644
> index 00000000000..89cf475cee1
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-elide-rev-perms-5.c
> @@ -0,0 +1,42 @@
> +/* { dg-require-effective-target vect_int } */
> +/* { dg-options "-O2 -ftree-vectorize -fdump-tree-vect-details" } */
> +
> +#include "tree-vect.h"
> +
> +__attribute__((noipa))
> +int
> +foo (int *a)
> +{
> +  int x = 100;
> +  for (int i = 99; i >= 0; i--)
> +    {
> +      x = a[i];
> +      a[i] = x * 2;
> +    }
> +  return x - 1;
> +}
> +
> +int
> +main ()
> +{
> +  check_vect ();
> +
> +  int a[100];
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    a[i] = i;
> +
> +  int x = foo (a);
> +
> +#pragma GCC novector
> +  for (int i = 0; i < 100; i++)
> +    if (a[i] != 2 * i)
> +      __builtin_abort ();
> +
> +  if (x != -1)
> +    __builtin_abort ();
> +}
> +
> +/* { dg-final { scan-tree-dump-not "Eliding reverse permutation for load" 
> "vect" } } */
> +/* { dg-final { scan-tree-dump-not "Eliding reverse permutation for store" 
> "vect" } } */
> \ No newline at end of file
> diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
> index fc08d10b872..725f686d26a 100644
> --- a/gcc/tree-vect-slp.cc
> +++ b/gcc/tree-vect-slp.cc
> @@ -4213,6 +4213,7 @@ vect_build_slp_instance (vec_info *vinfo,
>        new_instance->cost_vec = vNULL;
>        new_instance->leader_instance = NULL;
>        new_instance->subgraph_entries = vNULL;
> +      new_instance->elide_rev_perms_p = false;
>  
>        if (dump_enabled_p ())
>       dump_printf_loc (MSG_NOTE, vect_location,
> @@ -4587,6 +4588,7 @@ vect_analyze_slp_reduc_chain (loop_vec_info vinfo,
>        new_instance->cost_vec = vNULL;
>        new_instance->leader_instance = NULL;
>        new_instance->subgraph_entries = vNULL;
> +      new_instance->elide_rev_perms_p = false;
>  
>        vinfo->slp_instances.safe_push (new_instance);
>  
> @@ -4652,6 +4654,7 @@ vect_analyze_slp_reduc_chain (loop_vec_info vinfo,
>        new_instance->cost_vec = vNULL;
>        new_instance->leader_instance = NULL;
>        new_instance->subgraph_entries = vNULL;
> +      new_instance->elide_rev_perms_p = false;
>  
>        vect_reduc_info reduc_info = info_for_reduction (vinfo, node);
>        reduc_info->is_reduc_chain = true;
> @@ -4791,6 +4794,7 @@ vect_analyze_slp_reduction (loop_vec_info vinfo,
>        new_instance->cost_vec = vNULL;
>        new_instance->leader_instance = NULL;
>        new_instance->subgraph_entries = vNULL;
> +      new_instance->elide_rev_perms_p = false;
>  
>        if (dump_enabled_p ())
>       dump_printf_loc (MSG_NOTE, vect_location,
> @@ -4862,6 +4866,7 @@ vect_analyze_slp_reduction_group (loop_vec_info 
> loop_vinfo,
>    new_instance->cost_vec = vNULL;
>    new_instance->leader_instance = NULL;
>    new_instance->subgraph_entries = vNULL;
> +  new_instance->elide_rev_perms_p = false;
>  
>    if (dump_enabled_p ())
>      dump_printf_loc (MSG_NOTE, vect_location,
> @@ -5087,6 +5092,7 @@ vect_analyze_slp_instance (vec_info *vinfo,
>        new_instance->cost_vec = vNULL;
>        new_instance->leader_instance = NULL;
>        new_instance->subgraph_entries = vNULL;
> +      new_instance->elide_rev_perms_p = false;
>  
>        if (dump_enabled_p ())
>       dump_printf_loc (MSG_NOTE, vect_location,
> @@ -5327,6 +5333,7 @@ vect_analyze_slp_instance (vec_info *vinfo,
>         new_instance->cost_vec = vNULL;
>         new_instance->leader_instance = NULL;
>         new_instance->subgraph_entries = vNULL;
> +       new_instance->elide_rev_perms_p = false;
>  
>         if (dump_enabled_p ())
>           dump_printf_loc (MSG_NOTE, vect_location,
> @@ -8512,6 +8519,97 @@ vect_cse_slp_node_parts (hash_set<slp_tree> &visited,
>        vect_cse_slp_node_parts (visited, part_starts, drops, child);
>  }
>  
> +/* Helper function for recursively checking if the SLP subtree rooted
> +   at NODE is suitable for reverse permutation elision.  */
> +
> +static bool
> +vect_can_elide_rev_perms_p (loop_vec_info loop_vinfo, slp_tree node)
> +{
> +  /* Reject permutation nodes.  */
> +  if (!node
> +      || SLP_TREE_PERMUTE_P (node))
> +    return false;
> +
> +  /* Constant and external defs are acceptable only if they are uniform
> +     vectors.  Reject other non-internal def types.  */
> +  vect_def_type def_type = SLP_TREE_DEF_TYPE (node);
> +  if (def_type == vect_constant_def
> +      || def_type == vect_external_def)
> +    return vect_slp_tree_uniform_p (node);
> +  else if (def_type != vect_internal_def)
> +    return false;
> +
> +  /* If the result of a statement is used outside the loop, eliding the
> +     reverse permutation could change the value observed by that use.  */
> +  stmt_vec_info stmt_info = SLP_TREE_REPRESENTATIVE (node);
> +  if (!stmt_info
> +      || STMT_VINFO_LIVE_P (stmt_info))
> +    return false;

Checking STMT_VINFO_LIVE_P on the representative is not enough,
you have to traverse all SLP_TREE_SCALAR_STMTS and check on those.

> +
> +  /* Only accept data references and GIMPLE assigns for now.  */
> +  if (STMT_VINFO_DATA_REF (stmt_info))
> +    {
> +      /* The final VMAT is unknown at this point, so here we only reject
> +      obvious non-candidates.  */
> +      if (STMT_VINFO_STRIDED_P (stmt_info)
> +       || STMT_VINFO_GATHER_SCATTER_P (stmt_info)
> +       || compare_step_with_zero (loop_vinfo, stmt_info) >= 0)
> +     return false;
> +    }
> +  else if (!is_gimple_assign (stmt_info->stmt))
> +    return false;
> +
> +  poly_uint64 nunits = TYPE_VECTOR_SUBPARTS (SLP_TREE_VECTYPE (node));
> +  for (slp_tree child : SLP_TREE_CHILDREN (node))
> +    {
> +      /* Reverse permutations can cancel each other out only if both nodes
> +      have the same number of elements per vector.  */
> +      if (child
> +       && SLP_TREE_DEF_TYPE (child) == vect_internal_def
> +       && maybe_ne (nunits, TYPE_VECTOR_SUBPARTS (SLP_TREE_VECTYPE (child))))
> +     return false;
> +
> +      /* Recursively check the child.  */
> +      if (!vect_can_elide_rev_perms_p (loop_vinfo, child))

You have to use a visited set to track already visited node, otherwise
you'll run into cycles and exponential complexity because you are
traversing a geneal directed graph.

> +     return false;
> +    }
> +
> +  return true;
> +}
> +
> +/* Identify SLP subgraphs in which reverse permutations for negative-step
> +   contiguous DRs might be elided.  Record the tentative decision in
> +   elide_rev_perms_p on each subgraph leader.  The flag can be cleared
> +   later if one of the final VMATs is not VMAT_CONTIGUOUS_REVERSE.  */
> +
> +static void
> +vect_analyze_rev_perms_elision (vec_info *vinfo)
> +{
> +  loop_vec_info loop_vinfo = dyn_cast <loop_vec_info> (vinfo);
> +  if (!loop_vinfo)
> +    return;
> +
> +  /* Partition the SLP graph and initialize elide_rev_perms_p to true for
> +     leader SLP instances.  */
> +  vect_partition_graph (vinfo);
> +  for (auto inst : vinfo->slp_instances)
> +    if (inst->leader_instance == inst)
> +      inst->elide_rev_perms_p = true;
> +
> +  /* Clear the flag on the leader if reverse permutations cannot be elided.  
> */
> +  for (auto inst : vinfo->slp_instances)
> +    {
> +      slp_instance leader = inst->leader_instance;
> +      if (!leader->elide_rev_perms_p)
> +     continue;
> +
> +      slp_tree root = SLP_INSTANCE_TREE (inst);
> +      if (SLP_INSTANCE_KIND (inst) != slp_inst_kind_store
> +       || !vect_can_elide_rev_perms_p (loop_vinfo, root))
> +     leader->elide_rev_perms_p = false;
> +    }
> +}
> +
>  /* Optimize the SLP graph of VINFO.  */
>  
>  void
> @@ -8530,6 +8628,8 @@ vect_optimize_slp (vec_info *vinfo)
>  
>    release_scalar_stmts_to_slp_tree_map (bst_map);
>  
> +  vect_analyze_rev_perms_elision (vinfo);
> +
>    if (!is_a <bb_vec_info> (vinfo))
>      return;
>  
> diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
> index 09e45d0629a..dd7d670bea6 100644
> --- a/gcc/tree-vect-stmts.cc
> +++ b/gcc/tree-vect-stmts.cc
> @@ -8104,7 +8104,7 @@ vectorizable_scan_store (vec_info *vinfo, stmt_vec_info 
> stmt_info,
>  static bool
>  vectorizable_store (vec_info *vinfo,
>                   stmt_vec_info stmt_info, gimple_stmt_iterator *gsi,
> -                 slp_tree slp_node,
> +                 slp_tree slp_node, slp_instance node_instance,
>                   stmt_vector_for_cost *cost_vec)
>  {
>    tree data_ref;
> @@ -8128,6 +8128,7 @@ vectorizable_store (vec_info *vinfo,
>    poly_uint64 vf;
>    vec_load_store_type vls_type;
>    tree ref_type;
> +  bool elide_rev_perms_p = false;
>  
>    if (!STMT_VINFO_RELEVANT_P (stmt_info) && !bb_vinfo)
>      return false;
> @@ -8319,6 +8320,29 @@ vectorizable_store (vec_info *vinfo,
>                        "Vectorizing an unaligned access.\n");
>      }
>  
> +  /* Honor the reverse permutation elision decision of the SLP subgraph.
> +     During analysis, invalidate the decision if the final memory access
> +     type is not VMAT_CONTIGUOUS_REVERSE.  */
> +  if (loop_vinfo
> +      && node_instance
> +      && node_instance->leader_instance
> +      && node_instance->leader_instance->elide_rev_perms_p)
> +    {
> +      elide_rev_perms_p = true;
> +      if (costing_p
> +       && memory_access_type != VMAT_CONTIGUOUS_REVERSE)
> +     {
> +       elide_rev_perms_p = false;
> +       node_instance->leader_instance->elide_rev_perms_p = false;

I'm not sure it's sound to do this during analysis, we might
have used elide_rev_perms_p = true already, no?

> +     }
> +
> +      if (!costing_p
> +       && dump_enabled_p ()
> +       && elide_rev_perms_p)
> +     dump_printf_loc (MSG_NOTE, vect_location,
> +                      "Eliding reverse permutation for store.\n");
> +    }
> +
>    /* Transform.  */
>  
>    if (!costing_p)
> @@ -9363,7 +9387,8 @@ vectorizable_store (vec_info *vinfo,
>        if (!costing_p)
>       vec_oprnd = vec_oprnds[i];
>  
> -      if (memory_access_type == VMAT_CONTIGUOUS_REVERSE)
> +      if (memory_access_type == VMAT_CONTIGUOUS_REVERSE
> +       && !elide_rev_perms_p)
>       {
>         if (costing_p)
>           inside_cost += record_stmt_cost (cost_vec, 1, vec_perm,
> @@ -9711,7 +9736,7 @@ hoist_defs_of_uses (gimple *stmt, class loop *loop, 
> bool hoist_p)
>  static bool
>  vectorizable_load (vec_info *vinfo,
>                  stmt_vec_info stmt_info, gimple_stmt_iterator *gsi,
> -                slp_tree slp_node,
> +                slp_tree slp_node, slp_instance node_instance,
>                  stmt_vector_for_cost *cost_vec)
>  {
>    tree scalar_dest;
> @@ -9746,6 +9771,7 @@ vectorizable_load (vec_info *vinfo,
>    tree ref_type;
>    enum vect_def_type mask_dt = vect_unknown_def_type;
>    enum vect_def_type els_dt = vect_unknown_def_type;
> +  bool elide_rev_perms_p = false;
>  
>    if (!STMT_VINFO_RELEVANT_P (stmt_info) && !bb_vinfo)
>      return false;
> @@ -9992,6 +10018,29 @@ vectorizable_load (vec_info *vinfo,
>       vinfo->any_known_not_updated_vssa = true;
>      }
>  
> +  /* Honor the reverse permutation elision decision of the SLP subgraph.
> +     During analysis, invalidate the decision if the final memory access
> +     type is not VMAT_CONTIGUOUS_REVERSE.  */
> +  if (loop_vinfo
> +      && node_instance
> +      && node_instance->leader_instance
> +      && node_instance->leader_instance->elide_rev_perms_p)
> +    {
> +      elide_rev_perms_p = true;
> +      if (costing_p
> +       && memory_access_type != VMAT_CONTIGUOUS_REVERSE)
> +     {
> +       elide_rev_perms_p = false;
> +       node_instance->leader_instance->elide_rev_perms_p = false;
> +     }
> +
> +      if (!costing_p
> +       && dump_enabled_p ()
> +       && elide_rev_perms_p)
> +     dump_printf_loc (MSG_NOTE, vect_location,
> +                      "Eliding reverse permutation for load.\n");
> +    }
> +
>    /* For now just use the first available else value.
>       get_supported_else_vals tries MASK_LOAD_ELSE_ZERO first so we will
>       select it here if it is supported.  */
> @@ -11909,7 +11958,8 @@ vectorizable_load (vec_info *vinfo,
>           }
>       }
>  
> -      if (memory_access_type == VMAT_CONTIGUOUS_REVERSE)
> +      if (memory_access_type == VMAT_CONTIGUOUS_REVERSE
> +       && !elide_rev_perms_p)
>       {
>         if (costing_p)
>           inside_cost = record_stmt_cost (cost_vec, 1, vec_perm,
> @@ -13089,8 +13139,10 @@ vect_analyze_stmt (vec_info *vinfo,
>         || vectorizable_conversion (vinfo, stmt_info, NULL, node, cost_vec)
>         || vectorizable_operation (vinfo, stmt_info, NULL, node, cost_vec)
>         || vectorizable_assignment (vinfo, stmt_info, NULL, node, cost_vec)
> -       || vectorizable_load (vinfo, stmt_info, NULL, node, cost_vec)
> -       || vectorizable_store (vinfo, stmt_info, NULL, node, cost_vec)
> +       || vectorizable_load (vinfo, stmt_info, NULL, node, node_instance,
> +                             cost_vec)
> +       || vectorizable_store (vinfo, stmt_info, NULL, node, node_instance,
> +                              cost_vec)
>         || vectorizable_shift (vinfo, stmt_info, NULL, node, cost_vec)
>         || vectorizable_condition (vinfo, stmt_info, NULL, node, cost_vec)
>         || vectorizable_comparison (vinfo, stmt_info, NULL, node, cost_vec)
> @@ -13185,12 +13237,14 @@ vect_transform_stmt (vec_info *vinfo,
>        break;
>  
>      case load_vec_info_type:
> -      done = vectorizable_load (vinfo, stmt_info, gsi, slp_node, NULL);
> +      done = vectorizable_load (vinfo, stmt_info, gsi, slp_node,
> +                             slp_node_instance, NULL);
>        gcc_assert (done);
>        break;
>  
>      case store_vec_info_type:
> -      done = vectorizable_store (vinfo, stmt_info, gsi, slp_node, NULL);
> +      done = vectorizable_store (vinfo, stmt_info, gsi, slp_node,
> +                              slp_node_instance, NULL);
>        gcc_assert (done);
>        break;
>  
> diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
> index d8b1bef98cd..c4e49a3ff26 100644
> --- a/gcc/tree-vectorizer.h
> +++ b/gcc/tree-vectorizer.h
> @@ -460,6 +460,10 @@ public:
>    /* The type of operation the SLP instance is performing.  */
>    slp_instance_kind kind;
>  
> +  /* For a subgraph leader, whether reverse permutations throughout the
> +     subgraph can be elided.  Only meaningful for leader instances.  */
> +  bool elide_rev_perms_p;
> +
>    dump_user_location_t location () const;
>  } *slp_instance;
>  
> 

-- 
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Jochen Jaser, Andrew McDonald, Abhinav Puri; (HRB 36809, AG Nuernberg)

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