load and store-lanes with SLP

The following is a prototype for how to represent load/store-lanes
within SLP.  I've for now settled with having a single load node
with multiple permute nodes acting as selection, one for each loaded lane
and a single store node fed from all stored lanes.  For

  for (int i = 0; i < 1024; ++i)
    {
      a[2*i] = b[2*i] + 7;
      a[2*i+1] = b[2*i+1] * 3;
    }

you have the following SLP graph where I explain how things are set
up and code-generated:

t.c:23:21: note:   SLP graph after lowering permutations:
t.c:23:21: note:   node 0x50dc8b0 (max_nunits=1, refcnt=1) vector(4) int
t.c:23:21: note:   op template: *_6 = _7;
t.c:23:21: note:        stmt 0 *_6 = _7;
t.c:23:21: note:        stmt 1 *_12 = _13;
t.c:23:21: note:        children 0x50dc488 0x50dc6e8

This is the store node, it's marked with ldst_lanes = true during
SLP discovery.  This node code-generates

  vect_array.65[0] = vect__7.61_29;
  vect_array.65[1] = vect__13.62_28;
  MEM <int[8]> [(int *)vectp_a.63_27] = .STORE_LANES (vect_array.65);

...
t.c:23:21: note:   node 0x50dc520 (max_nunits=4, refcnt=2) vector(4) int
t.c:23:21: note:   op: VEC_PERM_EXPR
t.c:23:21: note:        stmt 0 _5 = *_4;
t.c:23:21: note:        lane permutation { 0[0] }
t.c:23:21: note:        children 0x50dc948
t.c:23:21: note:   node 0x50dc780 (max_nunits=4, refcnt=2) vector(4) int
t.c:23:21: note:   op: VEC_PERM_EXPR
t.c:23:21: note:        stmt 0 _11 = *_10;
t.c:23:21: note:        lane permutation { 0[1] }
t.c:23:21: note:        children 0x50dc948

These are the selection nodes, marked with ldst_lanes = true.
They code generate nothing.

t.c:23:21: note:   node 0x50dc948 (max_nunits=4, refcnt=3) vector(4) int
t.c:23:21: note:   op template: _5 = *_4;
t.c:23:21: note:        stmt 0 _5 = *_4;
t.c:23:21: note:        stmt 1 _11 = *_10;
t.c:23:21: note:        load permutation { 0 1 }

This is the load node, marked with ldst_lanes = true (the load
permutation is only accurate when taking into account the lane permute
in the selection nodes).  It code generates

  vect_array.58 = .LOAD_LANES (MEM <int[8]> [(int *)vectp_b.56_33]);
  vect__5.59_31 = vect_array.58[0];
  vect__5.60_30 = vect_array.58[1];

This scheme allows to leave code generation in vectorizable_load/store
mostly as-is.

While this should support both load-lanes and (masked) store-lanes
the decision to do either is done during SLP discovery time and
cannot be reversed without altering the SLP tree - as-is the SLP
tree is not usable for non-store-lanes on the store side, the
load side is OK representation-wise but will very likely fail
permute handling as the lowering to deal with the two input vector
restriction isn't done - but of course since the permute node is
marked as to be ignored that doesn't work out.  So I've put
restrictions in place that fail vectorization if a load/store-lane
SLP tree is later classified differently by get_load_store_type.

I'll note that for example gcc.target/aarch64/sve/mask_struct_store_3.c
will not get SLP store-lanes used because the full store SLPs just
fine though we then fail to handle the "splat" load-permutation

t2.c:5:21: note:   node 0x4db2630 (max_nunits=4, refcnt=2) vector([4,4]) int
t2.c:5:21: note:   op template: _6 = *_5;
t2.c:5:21: note:        stmt 0 _6 = *_5;
t2.c:5:21: note:        stmt 1 _6 = *_5;
t2.c:5:21: note:        stmt 2 _6 = *_5;
t2.c:5:21: note:        stmt 3 _6 = *_5;
t2.c:5:21: note:        load permutation { 0 0 0 0 }

the load permute lowering code currently doesn't consider it worth
lowering single loads from a group (or in this case not grouped loads).
The expectation is the target can handle this by two interleaves with
itself.

So what we see here is that while the explicit SLP representation is
helpful in some cases, in cases like this it would require changing
it when we make decisions how to vectorize.  My idea is that this
all will change a lot when we re-do SLP discovery (for loops) and
when we get rid of non-SLP as I think vectorizable_* should be
allowed to alter the SLP graph during analysis.

The patch also removes the code cancelling SLP if we can use
load/store-lanes from the main loop vector analysis code and
re-implements it as re-discovering the SLP instance with
forced single-lane splits so SLP load/store-lanes scheme can be
used.

This is now done after SLP discovery and SLP pattern recog are
complete to not disturb the latter but per SLP instance instead
of being a global decision on the whole loop.

This is a behavioral change that for example shows in
gcc.dg/vect/slp-perm-6.c on ARM where we formerly used SLP permutes
but now a mix of SLP without permutes and load/store lanes.  The
previous flaky heuristic is now flaky in a different way.

Testing on RISC-V and aarch64 reveal several testcases that require
adjustment as to now expect SLP even when load/store lanes are being
used.  If in doubt I've adjusted them to the final expectation which
will lead to one or two new FAILs where we still do the SLP cancelling.
I have a followup that implements that while remaining in SLP that's
in final testing.

Note that gcc.dg/vect/slp-42.c and gcc.dg/vect/pr68445.c will FAIL
on aarch64 with SVE because for some odd reason vect_stridedN
is true for any N for check_effective_target_vect_fully_masked
targets but SVE cannot do ld8 while risc-v can.

I have not bothered to adjust target tests that now fail assembly-scan.

	* tree-vectorizer.h (_slp_tree::ldst_lanes): New flag to mark
	load, store and permute nodes.
	* tree-vect-slp.cc (_slp_tree::_slp_tree): Initialize ldst_lanes.
	(vect_build_slp_instance): For stores iff the target prefers
	store-lanes discover single-lane sub-groups, do not perform
	interleaving lowering but mark the node with ldst_lanes.
	Also allow i == 0 - fatal failure - for splitting up a store group
	when we're not doing single-lane discovery already.
	(vect_lower_load_permutations): When the target supports
	load lanes and the loads all fit the pattern split out
	a single level of permutes only and mark the load and
	permute nodes with ldst_lanes.
	(vectorizable_slp_permutation_1): Handle the load-lane permute
	forwarding of vector defs.
	(vect_analyze_slp): After SLP pattern recog is finished see if
	there are any SLP instances that would benefit from using
	load/store-lanes and re-discover those with forced single lanes.
	* tree-vect-stmts.cc (get_group_load_store_type): Support
	load/store-lanes for SLP.
	(vectorizable_store): Support SLP code generation for store-lanes.
	(vectorizable_load): Support SLP code generation for load-lanes.
	* tree-vect-loop.cc (vect_analyze_loop_2): Do not cancel SLP
	when store-lanes can be used.

	* gcc.dg/vect/slp-55.c: New testcase.
	* gcc.dg/vect/slp-56.c: Likewise.
	* gcc.dg/vect/slp-11c.c: Adjust.
	* gcc.dg/vect/slp-53.c: Likewise.
	* gcc.dg/vect/slp-cond-1.c: Likewise.
	* gcc.dg/vect/vect-complex-5.c: Likewise.
	* gcc.dg/vect/slp-1.c: Likewise.
	* gcc.dg/vect/slp-54.c: Remove riscv XFAIL.
	* gcc.dg/vect/slp-perm-5.c: Adjust.
	* gcc.dg/vect/slp-perm-7.c: Likewise.
	* gcc.dg/vect/slp-perm-8.c: Likewise.
	* gcc.dg/vect/slp-multitypes-11.c: Likewise.
	* gcc.dg/vect/slp-multitypes-11-big-array.c: Likewise.
	* gcc.dg/vect/slp-perm-9.c: Remove expected SLP fail due to
	three-vector permute.
	* gcc.dg/vect/slp-perm-6.c: Remove XFAIL.
	* gcc.dg/vect/slp-perm-1.c: Adjust.
	* gcc.dg/vect/slp-perm-2.c: Likewise.
	* gcc.dg/vect/slp-perm-3.c: Likewise.
	* gcc.dg/vect/slp-perm-4.c: Likewise.
	* gcc.dg/vect/pr68445.c: Likewise.
	* gcc.dg/vect/slp-11b.c: Likewise.
	* gcc.dg/vect/slp-2.c: Likewise.
	* gcc.dg/vect/slp-23.c: Likewise.
	* gcc.dg/vect/slp-33.c: Likewise.
	* gcc.dg/vect/slp-42.c: Likewise.
	* gcc.dg/vect/slp-46.c: Likewise.
	* gcc.dg/vect/slp-perm-10.c: Likewise.

31 files changed, 458 insertions, 172 deletions

diff --git a/gcc/testsuite/gcc.dg/vect/pr68445.c b/gcc/testsuite/gcc.dg/vect/pr68445.c
index 15bffdc..71d61b9 100644
--- a/gcc/testsuite/gcc.dg/vect/pr68445.c
+++ b/gcc/testsuite/gcc.dg/vect/pr68445.c
@@ -16,4 +16,4 @@ void IMB_double_fast_x (int *destf, int *dest, int y, int *p1f)
     }
 }
 
-/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { xfail vect_variable_length } } } */
+/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { xfail { vect_variable_length && { ! vect_strided8 } } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-1.c b/gcc/testsuite/gcc.dg/vect/slp-1.c
index d4a13f1..e1a45e1 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-1.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-1.c
@@ -122,5 +122,4 @@ int main (void)
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 4 loops" 1 "vect"  } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" { target {! vect_strided5 } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 3 "vect" { target vect_strided5 } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-11b.c b/gcc/testsuite/gcc.dg/vect/slp-11b.c
index df64c8d..0208f03 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-11b.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-11b.c
@@ -45,4 +45,4 @@ int main (void)
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { { vect_strided4 || vect_perm } && vect_int_mult } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm && vect_int_mult } xfail vect_load_lanes } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm && vect_int_mult } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-11c.c b/gcc/testsuite/gcc.dg/vect/slp-11c.c
index 2e70fca..25d7f2c 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-11c.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-11c.c
@@ -45,5 +45,4 @@ int main (void)
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { { vect_uintfloat_cvt && vect_strided2 } && vect_int_mult } } } } */
 /* { dg-final { scan-tree-dump-times "vectorized 0 loops" 1 "vect" { target { ! { { vect_uintfloat_cvt && vect_strided2 } && vect_int_mult } } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target { vect_load_lanes } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { ! vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target { vect_load_lanes } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-2.c b/gcc/testsuite/gcc.dg/vect/slp-2.c
index d0de357..08d2116 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-2.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-2.c
@@ -144,5 +144,5 @@ int main (void)
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 4 loops" 1 "vect"  } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" { xfail vect_variable_length } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" } } */
   
diff --git a/gcc/testsuite/gcc.dg/vect/slp-23.c b/gcc/testsuite/gcc.dg/vect/slp-23.c
index 8836acf..d32ee5b 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-23.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-23.c
@@ -114,5 +114,5 @@ int main (void)
 /* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { ! vect_perm } } } } */
 /* SLP fails for the second loop with variable-length SVE because
    the load size is greater than the minimum vector size.  */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target vect_perm xfail { { aarch64_sve || riscv_v } && vect_variable_length } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target vect_perm xfail { aarch64_sve && vect_variable_length } } } } */
   
diff --git a/gcc/testsuite/gcc.dg/vect/slp-33.c b/gcc/testsuite/gcc.dg/vect/slp-33.c
index c382093..9c6c1e4 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-33.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-33.c
@@ -108,7 +108,7 @@ int main (void)
 /* { dg-final { scan-tree-dump-times "vectorized 3 loops" 1 "vect"  {target {vect_uintfloat_cvt && vect_int_mult} } } } */
 /* { dg-final { scan-tree-dump-times "vectorized 2 loops" 1 "vect"  {target {{! { vect_uintfloat_cvt}} && vect_int_mult} } } } */
 /* { dg-final { scan-tree-dump-times "vectorized 0 loops" 1 "vect"  {target {{! { vect_uintfloat_cvt}} && {! {vect_int_mult}}} } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 3 "vect" {target {vect_uintfloat_cvt && vect_int_mult} xfail { vect_variable_length && vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 3 "vect" {target {vect_uintfloat_cvt && vect_int_mult} } } } */
 /* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect"  {target {{! { vect_uintfloat_cvt}} && vect_int_mult} } } } */
 /* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect"  {target {{! { vect_uintfloat_cvt}} && {! {vect_int_mult}}} } } } */
   
diff --git a/gcc/testsuite/gcc.dg/vect/slp-42.c b/gcc/testsuite/gcc.dg/vect/slp-42.c
index 6b78246..53eca6b 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-42.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-42.c
@@ -15,5 +15,5 @@ void foo (int n)
     }
 }
 
-/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { xfail vect_variable_length } } } */
+/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { xfail { vect_variable_length && { ! vect_strided8 } } } } } */
 /* { dg-final { scan-tree-dump "vectorized 1 loops" "vect" } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-46.c b/gcc/testsuite/gcc.dg/vect/slp-46.c
index bf44547..b44a673 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-46.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-46.c
@@ -98,4 +98,4 @@ main ()
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" { xfail vect_load_lanes } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" { xfail { vect_load_lanes && vect_variable_length } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-53.c b/gcc/testsuite/gcc.dg/vect/slp-53.c
index d8cd5f8..50b3e9d 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-53.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-53.c
@@ -12,4 +12,5 @@ void foo (int * __restrict x, int *y)
     }
 }
 
-/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { target { vect_int && vect_int_mult } xfail vect_load_lanes } } } */
+/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { target { vect_int && vect_int_mult } } } } */
+/* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target { vect_load_lanes } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-54.c b/gcc/testsuite/gcc.dg/vect/slp-54.c
index ab66b34..57268ab 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-54.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-54.c
@@ -15,4 +15,4 @@ void foo (int * __restrict x, int *y)
     }
 }
 
-/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { target { vect_int && vect_int_mult } xfail riscv*-*-* } } } */
+/* { dg-final { scan-tree-dump "vectorizing stmts using SLP" "vect" { target { vect_int && vect_int_mult } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-55.c b/gcc/testsuite/gcc.dg/vect/slp-55.c
new file mode 100644
index 0000000..0bf65ef
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/slp-55.c
@@ -0,0 +1,37 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_int } */
+/* { dg-require-effective-target vect_int_mult } */
+/* { dg-additional-options "-fdump-tree-optimized" } */
+
+void foo (int * __restrict a, int *b, int *c)
+{
+  for (int i = 0; i < 1024; ++i)
+    {
+      a[2*i] = b[i] + 7;
+      a[2*i+1] = c[i] * 3;
+    }
+}
+
+int bar (int *b)
+{
+  int res = 0;
+  for (int i = 0; i < 1024; ++i)
+    {
+      res += b[2*i] + 7;
+      res += b[2*i+1] * 3;
+    }
+  return res;
+}
+
+void baz (int * __restrict a, int *b)
+{
+  for (int i = 0; i < 1024; ++i)
+    {
+      a[2*i] = b[2*i] + 7;
+      a[2*i+1] = b[2*i+1] * 3;
+    }
+}
+
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 3 "vect" } } */
+/* { dg-final { scan-tree-dump-times "LOAD_LANES" 2 "optimized" { target vect_load_lanes } } } */
+/* { dg-final { scan-tree-dump-times "STORE_LANES" 2 "optimized" { target vect_load_lanes } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-56.c b/gcc/testsuite/gcc.dg/vect/slp-56.c
new file mode 100644
index 0000000..0b985ea
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/slp-56.c
@@ -0,0 +1,51 @@
+#include "tree-vect.h"
+
+/* This is a load-lane / masked-store-lane test that more reliably
+   triggers SLP than SVEs mask_srtuct_store_*.c  */
+
+void __attribute__ ((noipa))
+test4 (int *__restrict dest, int *__restrict src,
+       int *__restrict cond, int bias, int n)
+{
+  for (int i = 0; i < n; ++i)
+    {
+      int value0 = src[i * 4] + bias;
+      int value1 = src[i * 4 + 1] * bias;
+      int value2 = src[i * 4 + 2] + bias;
+      int value3 = src[i * 4 + 3] * bias;
+      if (cond[i])
+        {
+          dest[i * 4] = value0;
+          dest[i * 4 + 1] = value1;
+          dest[i * 4 + 2] = value2;
+          dest[i * 4 + 3] = value3;
+        }
+    }
+}
+
+int dest[16*4];
+int src[16*4];
+int cond[16];
+const int dest_chk[16*4] = {0, 0, 0, 0, 9, 25, 11, 35, 0, 0, 0, 0, 17, 65, 19,
+    75, 0, 0, 0, 0, 25, 105, 27, 115, 0, 0, 0, 0, 33, 145, 35, 155, 0, 0, 0,
+    0, 41, 185, 43, 195, 0, 0, 0, 0, 49, 225, 51, 235, 0, 0, 0, 0, 57, 265, 59,
+    275, 0, 0, 0, 0, 65, 305, 67, 315};
+
+int main()
+{
+  check_vect ();
+#pragma GCC novector
+  for (int i = 0; i < 16; ++i)
+    cond[i] = i & 1;
+#pragma GCC novector
+  for (int i = 0; i < 16 * 4; ++i)
+    src[i] = i;
+  test4 (dest, src, cond, 5, 16);
+#pragma GCC novector
+  for (int i = 0; i < 16 * 4; ++i)
+    if (dest[i] != dest_chk[i])
+      abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target { vect_variable_length && vect_load_lanes } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-cond-1.c b/gcc/testsuite/gcc.dg/vect/slp-cond-1.c
index c76ea5d..16ab0cc 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-cond-1.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-cond-1.c
@@ -125,5 +125,4 @@ main ()
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" { target { ! vect_load_lanes } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 3 "vect" { target { vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 4 "vect" } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-multitypes-11-big-array.c b/gcc/testsuite/gcc.dg/vect/slp-multitypes-11-big-array.c
index 2792b93..07f871c 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-multitypes-11-big-array.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-multitypes-11-big-array.c
@@ -56,5 +56,4 @@ int main (void)
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { target vect_unpack } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect"  { target vect_unpack xfail { vect_variable_length && vect_load_lanes } } } } */
-
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect"  { target vect_unpack } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-multitypes-11.c b/gcc/testsuite/gcc.dg/vect/slp-multitypes-11.c
index 5c75dc1..0f7b479 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-multitypes-11.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-multitypes-11.c
@@ -51,5 +51,5 @@ int main (void)
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { target vect_unpack } } } */
 /* The epilogues are vectorized using partial vectors.  */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect"  { target { vect_unpack && { { ! vect_partial_vectors_usage_1 } || s390_vx } } xfail { vect_variable_length && vect_load_lanes } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect"  { target { { vect_unpack && vect_partial_vectors_usage_1 } && { ! s390_vx } } xfail { vect_variable_length && vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect"  { target { vect_unpack && { { ! vect_partial_vectors_usage_1 } || s390_vx } } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect"  { target { { vect_unpack && vect_partial_vectors_usage_1 } && { ! s390_vx } } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-1.c b/gcc/testsuite/gcc.dg/vect/slp-perm-1.c
index dbb107f..93b5907 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-1.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-1.c
@@ -81,9 +81,8 @@ int main (int argc, const char* argv[])
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { target vect_perm } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm3_int && {! vect_load_lanes } } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target vect_load_lanes } } } */
-/* { dg-final { scan-tree-dump "Built SLP cancelled: can use load/store-lanes" "vect" { target { vect_perm3_int && vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm3_int || vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump "can use load/store-lanes" "vect" { target { vect_perm3_int && vect_load_lanes } } } } */
 /* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target vect_load_lanes } } } */
 /* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target vect_load_lanes } } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-10.c b/gcc/testsuite/gcc.dg/vect/slp-perm-10.c
index 03de4c6..2cce30c 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-10.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-10.c
@@ -53,4 +53,4 @@ int main ()
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_perm } } } */
 /* SLP fails for variable-length SVE because the load size is greater
    than the minimum vector size.  */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target vect_perm xfail { { aarch64_sve || riscv_v } && vect_variable_length } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target vect_perm xfail { aarch64_sve && vect_variable_length } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-2.c b/gcc/testsuite/gcc.dg/vect/slp-perm-2.c
index 41fd159..6ac29e7 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-2.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-2.c
@@ -55,8 +55,6 @@ int main (int argc, const char* argv[])
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { target vect_perm } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm && {! vect_load_lanes } } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target vect_load_lanes } } } */
-/* { dg-final { scan-tree-dump "Built SLP cancelled: can use load/store-lanes" "vect" { target { vect_perm && vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm || vect_load_lanes  } } } } */
 /* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target vect_load_lanes } } } */
 /* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target vect_load_lanes } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-3.c b/gcc/testsuite/gcc.dg/vect/slp-perm-3.c
index 9ea35ba..d1953054 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-3.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-3.c
@@ -68,9 +68,7 @@ int main (int argc, const char* argv[])
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { target vect_perm } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm && {! vect_load_lanes } } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target vect_load_lanes } } } */
-/* { dg-final { scan-tree-dump "Built SLP cancelled: can use load/store-lanes" "vect" { target { vect_perm && vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm || vect_load_lanes } } } } */
 /* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target vect_load_lanes } } } */
 /* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target vect_load_lanes } } } */
 
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-4.c b/gcc/testsuite/gcc.dg/vect/slp-perm-4.c
index f4bda39..107968f 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-4.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-4.c
@@ -115,4 +115,4 @@ int main (int argc, const char* argv[])
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" } } */
 /* { dg-final { scan-tree-dump-times "gaps requires scalar epilogue loop" 0 "vect" } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { ! { vect_load_lanes && vect_strided5 } } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-5.c b/gcc/testsuite/gcc.dg/vect/slp-perm-5.c
index 7128cf4..0dedd4a 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-5.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-5.c
@@ -105,9 +105,6 @@ int main (int argc, const char* argv[])
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { target vect_perm } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target { vect_perm3_int && { ! vect_load_lanes } } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target vect_load_lanes } } } */
-/* { dg-final { scan-tree-dump "Built SLP cancelled: can use load/store-lanes" "vect" { target { vect_perm3_int && vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target { vect_perm3_int || vect_load_lanes } } } } */
 /* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target vect_load_lanes } } } */
 /* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target vect_load_lanes } } } */
-
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-6.c b/gcc/testsuite/gcc.dg/vect/slp-perm-6.c
index 5cc6261..000848c 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-6.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-6.c
@@ -106,5 +106,5 @@ int main (int argc, const char* argv[])
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { target vect_perm } } } */
 /* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target vect_perm3_int } } } */
 /* { dg-final { scan-tree-dump "Built SLP cancelled: can use load/store-lanes" "vect" { target { vect_perm3_int && vect_load_lanes } xfail *-*-* } } } */
-/* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target vect_load_lanes xfail vect_perm3_int } } } */
-/* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target vect_load_lanes xfail vect_perm3_int } } } */
+/* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target vect_load_lanes } } } */
+/* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target vect_load_lanes } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-7.c b/gcc/testsuite/gcc.dg/vect/slp-perm-7.c
index df13c37..f15736e 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-7.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-7.c
@@ -97,8 +97,6 @@ int main (int argc, const char* argv[])
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  { target vect_perm } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm3_int && { ! vect_load_lanes } } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target vect_load_lanes } } } */
-/* { dg-final { scan-tree-dump "Built SLP cancelled: can use load/store-lanes" "vect" { target { vect_perm3_int && vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm3_int || vect_load_lanes } } } } */
 /* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target vect_load_lanes } } } */
 /* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target vect_load_lanes } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-8.c b/gcc/testsuite/gcc.dg/vect/slp-perm-8.c
index 029be54..7610524 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-8.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-8.c
@@ -61,10 +61,8 @@ int main (int argc, const char* argv[])
 }
 
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { vect_perm_byte } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm3_byte && { { ! vect_load_lanes } && { { ! vect_partial_vectors_usage_1 } || s390_vx } } } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm3_byte && { { ! vect_partial_vectors_usage_1 } || s390_vx } } } } } */
 /* The epilogues are vectorized using partial vectors.  */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target { vect_perm3_byte && { { ! vect_load_lanes } && { vect_partial_vectors_usage_1 && { ! s390_vx } } } } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target vect_load_lanes } } } */
-/* { dg-final { scan-tree-dump "Built SLP cancelled: can use load/store-lanes" "vect" { target { vect_perm3_byte && vect_load_lanes } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 2 "vect" { target { vect_perm3_byte && {  vect_partial_vectors_usage_1 && { ! s390_vx } } } } } } */
 /* { dg-final { scan-tree-dump "LOAD_LANES" "vect" { target vect_load_lanes } } } */
 /* { dg-final { scan-tree-dump "STORE_LANES" "vect" { target vect_load_lanes } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/slp-perm-9.c b/gcc/testsuite/gcc.dg/vect/slp-perm-9.c
index 89400fb..c9468d8 100644
--- a/gcc/testsuite/gcc.dg/vect/slp-perm-9.c
+++ b/gcc/testsuite/gcc.dg/vect/slp-perm-9.c
@@ -58,7 +58,5 @@ int main (int argc, const char* argv[])
 /* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target { { vect_perm_short || vect32 } || vect_load_lanes } } } } */
 /* We don't try permutes with a group size of 3 for variable-length
    vectors.  */
-/* { dg-final { scan-tree-dump "permutation requires at least three vectors" "vect" { target { vect_perm_short && { ! vect_perm3_short } } xfail vect_variable_length } } } */
-/* { dg-final { scan-tree-dump-not "permutation requires at least three vectors" "vect" { target vect_perm3_short } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target { { ! { vect_perm3_short || vect32 } } || vect_load_lanes } } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { { vect_perm3_short || vect32 } && { ! vect_load_lanes } } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target { ! { vect_perm3_short || { vect32 || vect_load_lanes } } } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { vect_perm3_short || { vect32 || vect_load_lanes } } } } } */
diff --git a/gcc/testsuite/gcc.dg/vect/vect-complex-5.c b/gcc/testsuite/gcc.dg/vect/vect-complex-5.c
index ac562dc..0d85072 100644
--- a/gcc/testsuite/gcc.dg/vect/vect-complex-5.c
+++ b/gcc/testsuite/gcc.dg/vect/vect-complex-5.c
@@ -40,5 +40,4 @@ main (void)
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 0 "vect" { target vect_load_lanes } } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target { ! vect_load_lanes } xfail { ! vect_hw_misalign } } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { xfail { ! vect_hw_misalign } } } } */
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 1fb7bbd..242d5e2 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -2958,82 +2958,6 @@ start_over:
 				       "unsupported SLP instances\n");
 	  goto again;
 	}
-
-      /* Check whether any load in ALL SLP instances is possibly permuted.  */
-      slp_tree load_node, slp_root;
-      unsigned i, x;
-      slp_instance instance;
-      bool can_use_lanes = true;
-      FOR_EACH_VEC_ELT (LOOP_VINFO_SLP_INSTANCES (loop_vinfo), x, instance)
-	{
-	  slp_root = SLP_INSTANCE_TREE (instance);
-	  int group_size = SLP_TREE_LANES (slp_root);
-	  tree vectype = SLP_TREE_VECTYPE (slp_root);
-	  bool loads_permuted = false;
-	  FOR_EACH_VEC_ELT (SLP_INSTANCE_LOADS (instance), i, load_node)
-	    {
-	      if (!SLP_TREE_LOAD_PERMUTATION (load_node).exists ())
-		continue;
-	      unsigned j;
-	      stmt_vec_info load_info;
-	      FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (load_node), j, load_info)
-		if (SLP_TREE_LOAD_PERMUTATION (load_node)[j] != j)
-		  {
-		    loads_permuted = true;
-		    break;
-		  }
-	    }
-
-	  /* If the loads and stores can be handled with load/store-lane
-	     instructions record it and move on to the next instance.  */
-	  if (loads_permuted
-	      && SLP_INSTANCE_KIND (instance) == slp_inst_kind_store
-	      && vect_store_lanes_supported (vectype, group_size, false)
-		   != IFN_LAST)
-	    {
-	      FOR_EACH_VEC_ELT (SLP_INSTANCE_LOADS (instance), i, load_node)
-		if (STMT_VINFO_GROUPED_ACCESS
-		      (SLP_TREE_REPRESENTATIVE (load_node)))
-		  {
-		    stmt_vec_info stmt_vinfo = DR_GROUP_FIRST_ELEMENT
-			(SLP_TREE_REPRESENTATIVE (load_node));
-		    /* Use SLP for strided accesses (or if we can't
-		       load-lanes).  */
-		    if (STMT_VINFO_STRIDED_P (stmt_vinfo)
-			|| vect_load_lanes_supported
-			     (STMT_VINFO_VECTYPE (stmt_vinfo),
-			      DR_GROUP_SIZE (stmt_vinfo), false) == IFN_LAST)
-		      break;
-		  }
-
-	      can_use_lanes
-		= can_use_lanes && i == SLP_INSTANCE_LOADS (instance).length ();
-
-	      if (can_use_lanes && dump_enabled_p ())
-		dump_printf_loc (MSG_NOTE, vect_location,
-				 "SLP instance %p can use load/store-lanes\n",
-				 (void *) instance);
-	    }
-	  else
-	    {
-	      can_use_lanes = false;
-	      break;
-	    }
-	}
-
-      /* If all SLP instances can use load/store-lanes abort SLP and try again
-	 with SLP disabled.  */
-      if (can_use_lanes)
-	{
-	  ok = opt_result::failure_at (vect_location,
-				       "Built SLP cancelled: can use "
-				       "load/store-lanes\n");
-	  if (dump_enabled_p ())
-	    dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
-			     "Built SLP cancelled: all SLP instances support "
-			     "load/store-lanes\n");
-	  goto again;
-	}
     }
 
   /* Dissolve SLP-only groups.  */
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 2304cda..5a65a99 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -121,6 +121,7 @@ _slp_tree::_slp_tree ()
   SLP_TREE_SIMD_CLONE_INFO (this) = vNULL;
   SLP_TREE_DEF_TYPE (this) = vect_uninitialized_def;
   SLP_TREE_CODE (this) = ERROR_MARK;
+  this->ldst_lanes = false;
   SLP_TREE_VECTYPE (this) = NULL_TREE;
   SLP_TREE_REPRESENTATIVE (this) = NULL;
   SLP_TREE_REF_COUNT (this) = 1;
@@ -3483,7 +3484,8 @@ static bool
 vect_analyze_slp_instance (vec_info *vinfo,
 			   scalar_stmts_to_slp_tree_map_t *bst_map,
 			   stmt_vec_info stmt_info, slp_instance_kind kind,
-			   unsigned max_tree_size, unsigned *limit);
+			   unsigned max_tree_size, unsigned *limit,
+			   bool force_single_lane = false);
 
 /* Build an interleaving scheme for the store sources RHS_NODES from
    SCALAR_STMTS.  */
@@ -3678,7 +3680,8 @@ vect_build_slp_instance (vec_info *vinfo,
 			 unsigned max_tree_size, unsigned *limit,
 			 scalar_stmts_to_slp_tree_map_t *bst_map,
 			 /* ???  We need stmt_info for group splitting.  */
-			 stmt_vec_info stmt_info_)
+			 stmt_vec_info stmt_info_,
+			 bool force_single_lane = false)
 {
   /* If there's no budget left bail out early.  */
   if (*limit == 0)
@@ -3707,9 +3710,17 @@ vect_build_slp_instance (vec_info *vinfo,
   poly_uint64 max_nunits = 1;
   unsigned tree_size = 0;
   unsigned i;
-  slp_tree node = vect_build_slp_tree (vinfo, scalar_stmts, group_size,
-				       &max_nunits, matches, limit,
-				       &tree_size, bst_map);
+
+  slp_tree node = NULL;
+  if (force_single_lane)
+    {
+      matches[0] = true;
+      matches[1] = false;
+    }
+  else
+    node = vect_build_slp_tree (vinfo, scalar_stmts, group_size,
+				&max_nunits, matches, limit,
+				&tree_size, bst_map);
   if (node != NULL)
     {
       /* Calculate the unrolling factor based on the smallest type.  */
@@ -3905,10 +3916,33 @@ vect_build_slp_instance (vec_info *vinfo,
       /* For loop vectorization split the RHS into arbitrary pieces of
 	 size >= 1.  */
       else if (is_a <loop_vec_info> (vinfo)
-	       && (i > 0 && i < group_size)
-	       && !vect_slp_prefer_store_lanes_p (vinfo,
-						  stmt_info, group_size, i))
-	{
+	       && (group_size != 1 && i < group_size))
+	{
+	  /* There are targets that cannot do even/odd interleaving schemes
+	     so they absolutely need to use load/store-lanes.  For now
+	     force single-lane SLP for them - they would be happy with
+	     uniform power-of-two lanes (but depending on element size),
+	     but even if we can use 'i' as indicator we would need to
+	     backtrack when later lanes fail to discover with the same
+	     granularity.  We cannot turn any of strided or scatter store
+	     into store-lanes.  */
+	  /* ???  If this is not in sync with what get_load_store_type
+	     later decides the SLP representation is not good for other
+	     store vectorization methods.  */
+	  bool want_store_lanes
+	    = (! STMT_VINFO_GATHER_SCATTER_P (stmt_info)
+	       && ! STMT_VINFO_STRIDED_P (stmt_info)
+	       && compare_step_with_zero (vinfo, stmt_info) > 0
+	       && vect_slp_prefer_store_lanes_p (vinfo, stmt_info,
+						 group_size, 1));
+	  if (want_store_lanes || force_single_lane)
+	    i = 1;
+
+	  /* A fatal discovery fail doesn't always mean single-lane SLP
+	     isn't a possibility, so try.  */
+	  if (i == 0)
+	    i = 1;
+
 	  if (dump_enabled_p ())
 	    dump_printf_loc (MSG_NOTE, vect_location,
 			     "Splitting SLP group at stmt %u\n", i);
@@ -3942,7 +3976,10 @@ vect_build_slp_instance (vec_info *vinfo,
 					       (max_nunits, end - start));
 		  rhs_nodes.safe_push (node);
 		  start = end;
-		  end = group_size;
+		  if (want_store_lanes || force_single_lane)
+		    end = start + 1;
+		  else
+		    end = group_size;
 		}
 	      else
 		{
@@ -3976,7 +4013,31 @@ vect_build_slp_instance (vec_info *vinfo,
 	    }
 
 	  /* Now we assume we can build the root SLP node from all stores.  */
-	  node = vect_build_slp_store_interleaving (rhs_nodes, scalar_stmts);
+	  if (want_store_lanes)
+	    {
+	      /* For store-lanes feed the store node with all RHS nodes
+		 in order.  */
+	      node = vect_create_new_slp_node (scalar_stmts,
+					       SLP_TREE_CHILDREN
+						 (rhs_nodes[0]).length ());
+	      SLP_TREE_VECTYPE (node) = SLP_TREE_VECTYPE (rhs_nodes[0]);
+	      node->ldst_lanes = true;
+	      SLP_TREE_CHILDREN (node)
+		.reserve_exact (SLP_TREE_CHILDREN (rhs_nodes[0]).length ()
+				+ rhs_nodes.length () - 1);
+	      /* First store value and possibly mask.  */
+	      SLP_TREE_CHILDREN (node)
+		.splice (SLP_TREE_CHILDREN (rhs_nodes[0]));
+	      /* Rest of the store values.  All mask nodes are the same,
+		 this should be guaranteed by dataref group discovery.  */
+	      for (unsigned j = 1; j < rhs_nodes.length (); ++j)
+		SLP_TREE_CHILDREN (node)
+		  .quick_push (SLP_TREE_CHILDREN (rhs_nodes[j])[0]);
+	      for (slp_tree child : SLP_TREE_CHILDREN (node))
+		child->refcnt++;
+	    }
+	  else
+	    node = vect_build_slp_store_interleaving (rhs_nodes, scalar_stmts);
 
 	  while (!rhs_nodes.is_empty ())
 	    vect_free_slp_tree (rhs_nodes.pop ());
@@ -4043,7 +4104,8 @@ vect_analyze_slp_instance (vec_info *vinfo,
 			   scalar_stmts_to_slp_tree_map_t *bst_map,
 			   stmt_vec_info stmt_info,
 			   slp_instance_kind kind,
-			   unsigned max_tree_size, unsigned *limit)
+			   unsigned max_tree_size, unsigned *limit,
+			   bool force_single_lane)
 {
   vec<stmt_vec_info> scalar_stmts;
 
@@ -4088,7 +4150,7 @@ vect_analyze_slp_instance (vec_info *vinfo,
 				      roots, remain,
 				      max_tree_size, limit, bst_map,
 				      kind == slp_inst_kind_store
-				      ? stmt_info : NULL);
+				      ? stmt_info : NULL, force_single_lane);
 
   /* ???  If this is slp_inst_kind_store and the above succeeded here's
      where we should do store group splitting.  */
@@ -4184,12 +4246,50 @@ vect_lower_load_permutations (loop_vec_info loop_vinfo,
      lower.  */
   stmt_vec_info first
     = DR_GROUP_FIRST_ELEMENT (SLP_TREE_SCALAR_STMTS (loads[0])[0]);
+  unsigned group_lanes = DR_GROUP_SIZE (first);
+
+  /* Verify if all load permutations can be implemented with a suitably
+     large element load-lanes operation.  */
+  unsigned ld_lanes_lanes = SLP_TREE_LANES (loads[0]);
+  if (STMT_VINFO_STRIDED_P (first)
+      || compare_step_with_zero (loop_vinfo, first) <= 0
+      || exact_log2 (ld_lanes_lanes) == -1
+      /* ???  For now only support the single-lane case as there is
+	 missing support on the store-lane side and code generation
+	 isn't up to the task yet.  */
+      || ld_lanes_lanes != 1
+      || vect_load_lanes_supported (SLP_TREE_VECTYPE (loads[0]),
+				    group_lanes / ld_lanes_lanes,
+				    false) == IFN_LAST)
+    ld_lanes_lanes = 0;
+  else
+    /* Verify the loads access the same number of lanes aligned to
+       ld_lanes_lanes.  */
+    for (slp_tree load : loads)
+      {
+	if (SLP_TREE_LANES (load) != ld_lanes_lanes)
+	  {
+	    ld_lanes_lanes = 0;
+	    break;
+	  }
+	unsigned first = SLP_TREE_LOAD_PERMUTATION (load)[0];
+	if (first % ld_lanes_lanes != 0)
+	  {
+	    ld_lanes_lanes = 0;
+	    break;
+	  }
+	for (unsigned i = 1; i < SLP_TREE_LANES (load); ++i)
+	  if (SLP_TREE_LOAD_PERMUTATION (load)[i] != first + i)
+	    {
+	      ld_lanes_lanes = 0;
+	      break;
+	    }
+      }
 
   /* Only a power-of-two number of lanes matches interleaving with N levels.
      ???  An even number of lanes could be reduced to 1<<ceil_log2(N)-1 lanes
      at each step.  */
-  unsigned group_lanes = DR_GROUP_SIZE (first);
-  if (exact_log2 (group_lanes) == -1 && group_lanes != 3)
+  if (ld_lanes_lanes == 0 && exact_log2 (group_lanes) == -1 && group_lanes != 3)
     return;
 
   for (slp_tree load : loads)
@@ -4206,7 +4306,8 @@ vect_lower_load_permutations (loop_vec_info loop_vinfo,
 	 with a non-1:1 load permutation around instead of canonicalizing
 	 those into a load and a permute node.  Removing this early
 	 check would do such canonicalization.  */
-      if (SLP_TREE_LANES (load) >= (group_lanes + 1) / 2)
+      if (SLP_TREE_LANES (load) >= (group_lanes + 1) / 2
+	  && ld_lanes_lanes == 0)
 	continue;
 
       /* First build (and possibly re-use) a load node for the
@@ -4239,10 +4340,20 @@ vect_lower_load_permutations (loop_vec_info loop_vinfo,
 	final_perm.quick_push
 	  (std::make_pair (0, SLP_TREE_LOAD_PERMUTATION (load)[i]));
 
+      if (ld_lanes_lanes != 0)
+	{
+	  /* ???  If this is not in sync with what get_load_store_type
+	     later decides the SLP representation is not good for other
+	     store vectorization methods.  */
+	  l0->ldst_lanes = true;
+	  load->ldst_lanes = true;
+	}
+
       while (1)
 	{
 	  unsigned group_lanes = SLP_TREE_LANES (l0);
-	  if (SLP_TREE_LANES (load) >= (group_lanes + 1) / 2)
+	  if (ld_lanes_lanes != 0
+	      || SLP_TREE_LANES (load) >= (group_lanes + 1) / 2)
 	    break;
 
 	  /* Try to lower by reducing the group to half its size using an
@@ -4570,6 +4681,94 @@ vect_analyze_slp (vec_info *vinfo, unsigned max_tree_size)
 	}
     }
 
+  /* Check whether we should force some SLP instances to use load/store-lanes
+     and do so by forcing SLP re-discovery with single lanes.  We used
+     to cancel SLP when this applied to all instances in a loop but now
+     we decide this per SLP instance.  It's important to do this only
+     after SLP pattern recognition.  */
+  if (is_a <loop_vec_info> (vinfo))
+    FOR_EACH_VEC_ELT (LOOP_VINFO_SLP_INSTANCES (vinfo), i, instance)
+      if (SLP_INSTANCE_KIND (instance) == slp_inst_kind_store
+	  && !SLP_INSTANCE_TREE (instance)->ldst_lanes)
+	{
+	  slp_tree slp_root = SLP_INSTANCE_TREE (instance);
+	  int group_size = SLP_TREE_LANES (slp_root);
+	  tree vectype = SLP_TREE_VECTYPE (slp_root);
+
+	  auto_vec<slp_tree> loads;
+	  hash_set<slp_tree> visited;
+	  vect_gather_slp_loads (loads, slp_root, visited);
+
+	  /* Check whether any load in the SLP instance is possibly
+	     permuted.  */
+	  bool loads_permuted = false;
+	  slp_tree load_node;
+	  unsigned j;
+	  FOR_EACH_VEC_ELT (loads, j, load_node)
+	    {
+	      if (!SLP_TREE_LOAD_PERMUTATION (load_node).exists ())
+		continue;
+	      unsigned k;
+	      stmt_vec_info load_info;
+	      FOR_EACH_VEC_ELT (SLP_TREE_SCALAR_STMTS (load_node), k, load_info)
+		if (SLP_TREE_LOAD_PERMUTATION (load_node)[k] != k)
+		  {
+		    loads_permuted = true;
+		    break;
+		  }
+	    }
+
+	  /* If the loads and stores can use load/store-lanes force re-discovery
+	     with single lanes.  */
+	  if (loads_permuted
+	      && !slp_root->ldst_lanes
+	      && vect_store_lanes_supported (vectype, group_size, false)
+	      != IFN_LAST)
+	    {
+	      bool can_use_lanes = true;
+	      FOR_EACH_VEC_ELT (loads, j, load_node)
+		if (STMT_VINFO_GROUPED_ACCESS
+		      (SLP_TREE_REPRESENTATIVE (load_node)))
+		  {
+		    stmt_vec_info stmt_vinfo = DR_GROUP_FIRST_ELEMENT
+			(SLP_TREE_REPRESENTATIVE (load_node));
+		    /* Use SLP for strided accesses (or if we can't
+		       load-lanes).  */
+		    if (STMT_VINFO_STRIDED_P (stmt_vinfo)
+			|| compare_step_with_zero (vinfo, stmt_vinfo) <= 0
+			|| vect_load_lanes_supported
+			     (STMT_VINFO_VECTYPE (stmt_vinfo),
+			      DR_GROUP_SIZE (stmt_vinfo), false) == IFN_LAST)
+		      {
+			can_use_lanes = false;
+			break;
+		      }
+		  }
+
+	      if (can_use_lanes)
+		{
+		  if (dump_enabled_p ())
+		    dump_printf_loc (MSG_NOTE, vect_location,
+				     "SLP instance %p can use load/store-lanes,"
+				     " re-discovering with single-lanes\n",
+				     (void *) instance);
+
+		  stmt_vec_info stmt_info = SLP_TREE_REPRESENTATIVE (slp_root);
+
+		  vect_free_slp_instance (instance);
+		  limit = max_tree_size;
+		  bool res = vect_analyze_slp_instance (vinfo, bst_map,
+							stmt_info,
+							slp_inst_kind_store,
+							max_tree_size, &limit,
+							true);
+		  gcc_assert (res);
+		  auto new_inst = LOOP_VINFO_SLP_INSTANCES (vinfo).pop ();
+		  LOOP_VINFO_SLP_INSTANCES (vinfo)[i] = new_inst;
+		}
+	    }
+	}
+
   /* When we end up with load permutations that we cannot possibly handle,
      like those requiring three vector inputs, lower them using interleaving
      like schemes.  */
@@ -9877,6 +10076,28 @@ vectorizable_slp_permutation_1 (vec_info *vinfo, gimple_stmt_iterator *gsi,
 
   gcc_assert (perm.length () == SLP_TREE_LANES (node));
 
+  /* Load-lanes permute.  This permute only acts as a forwarder to
+     select the correct vector def of the load-lanes load which
+     has the permuted vectors in its vector defs like
+     { v0, w0, r0, v1, w1, r1 ... } for a ld3.  */
+  if (node->ldst_lanes)
+    {
+      gcc_assert (children.length () == 1);
+      if (!gsi)
+	/* This is a trivial op always supported.  */
+	return 1;
+      slp_tree child = children[0];
+      unsigned vec_idx = (SLP_TREE_LANE_PERMUTATION (node)[0].second
+			  / SLP_TREE_LANES (node));
+      unsigned vec_num = SLP_TREE_LANES (child) / SLP_TREE_LANES (node);
+      for (unsigned i = 0; i < SLP_TREE_NUMBER_OF_VEC_STMTS (node); ++i)
+	{
+	  tree def = SLP_TREE_VEC_DEFS (child)[i * vec_num  + vec_idx];
+	  node->push_vec_def (def);
+	}
+      return 1;
+    }
+
   /* REPEATING_P is true if every output vector is guaranteed to use the
      same permute vector.  We can handle that case for both variable-length
      and constant-length vectors, but we only handle other cases for
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 72a29c0..d2282c0 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -1509,7 +1509,8 @@ check_load_store_for_partial_vectors (loop_vec_info loop_vinfo, tree vectype,
 
   unsigned int nvectors;
   if (slp_node)
-    nvectors = SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node);
+    /* ???  Incorrect for multi-lane lanes.  */
+    nvectors = SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node) / group_size;
   else
     nvectors = vect_get_num_copies (loop_vinfo, vectype);
 
@@ -1795,7 +1796,7 @@ vect_use_strided_gather_scatters_p (stmt_vec_info stmt_info,
    elements with a known constant step.  Return -1 if that step
    is negative, 0 if it is zero, and 1 if it is greater than zero.  */
 
-static int
+int
 compare_step_with_zero (vec_info *vinfo, stmt_vec_info stmt_info)
 {
   dr_vec_info *dr_info = STMT_VINFO_DR_INFO (stmt_info);
@@ -2070,6 +2071,14 @@ get_group_load_store_type (vec_info *vinfo, stmt_vec_info stmt_info,
 		 is irrelevant for them.  */
 	      *alignment_support_scheme = dr_unaligned_supported;
 	    }
+	  /* Try using LOAD/STORE_LANES.  */
+	  else if (slp_node->ldst_lanes
+		   && (*lanes_ifn
+			 = (vls_type == VLS_LOAD
+			    ? vect_load_lanes_supported (vectype, group_size, masked_p)
+			    : vect_store_lanes_supported (vectype, group_size,
+							  masked_p))) != IFN_LAST)
+	    *memory_access_type = VMAT_LOAD_STORE_LANES;
 	  else
 	    *memory_access_type = VMAT_CONTIGUOUS;
 
@@ -8201,6 +8210,16 @@ vectorizable_store (vec_info *vinfo,
 			    &lanes_ifn))
     return false;
 
+  if (slp_node
+      && slp_node->ldst_lanes
+      && memory_access_type != VMAT_LOAD_STORE_LANES)
+    {
+      if (dump_enabled_p ())
+	dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+			 "discovered store-lane but cannot use it.\n");
+      return false;
+    }
+
   if (mask)
     {
       if (memory_access_type == VMAT_CONTIGUOUS)
@@ -8717,7 +8736,7 @@ vectorizable_store (vec_info *vinfo,
   else
     {
       if (memory_access_type == VMAT_LOAD_STORE_LANES)
-	aggr_type = build_array_type_nelts (elem_type, vec_num * nunits);
+	aggr_type = build_array_type_nelts (elem_type, group_size * nunits);
       else
 	aggr_type = vectype;
       bump = vect_get_data_ptr_increment (vinfo, gsi, dr_info, aggr_type,
@@ -8774,11 +8793,24 @@ vectorizable_store (vec_info *vinfo,
 
   if (memory_access_type == VMAT_LOAD_STORE_LANES)
     {
-      gcc_assert (!slp && grouped_store);
+      if (costing_p && slp_node)
+	/* Update all incoming store operand nodes, the general handling
+	   above only handles the mask and the first store operand node.  */
+	for (slp_tree child : SLP_TREE_CHILDREN (slp_node))
+	  if (child != mask_node
+	      && !vect_maybe_update_slp_op_vectype (child, vectype))
+	    {
+	      if (dump_enabled_p ())
+		dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+				 "incompatible vector types for invariants\n");
+	      return false;
+	    }
       unsigned inside_cost = 0, prologue_cost = 0;
       /* For costing some adjacent vector stores, we'd like to cost with
 	 the total number of them once instead of cost each one by one. */
       unsigned int n_adjacent_stores = 0;
+      if (slp)
+	ncopies = SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node) / group_size;
       for (j = 0; j < ncopies; j++)
 	{
 	  gimple *new_stmt;
@@ -8796,7 +8828,7 @@ vectorizable_store (vec_info *vinfo,
 		  op = vect_get_store_rhs (next_stmt_info);
 		  if (costing_p)
 		    update_prologue_cost (&prologue_cost, op);
-		  else
+		  else if (!slp)
 		    {
 		      vect_get_vec_defs_for_operand (vinfo, next_stmt_info,
 						     ncopies, op,
@@ -8811,15 +8843,15 @@ vectorizable_store (vec_info *vinfo,
 		{
 		  if (mask)
 		    {
-		      vect_get_vec_defs_for_operand (vinfo, stmt_info, ncopies,
-						     mask, &vec_masks,
-						     mask_vectype);
+		      if (slp_node)
+			vect_get_slp_defs (mask_node, &vec_masks);
+		      else
+			vect_get_vec_defs_for_operand (vinfo, stmt_info, ncopies,
+						       mask, &vec_masks,
+						       mask_vectype);
 		      vec_mask = vec_masks[0];
 		    }
 
-		  /* We should have catched mismatched types earlier.  */
-		  gcc_assert (
-		    useless_type_conversion_p (vectype, TREE_TYPE (vec_oprnd)));
 		  dataref_ptr
 		    = vect_create_data_ref_ptr (vinfo, first_stmt_info,
 						aggr_type, NULL, offset, &dummy,
@@ -8831,10 +8863,16 @@ vectorizable_store (vec_info *vinfo,
 	      gcc_assert (!LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo));
 	      /* DR_CHAIN is then used as an input to
 		 vect_permute_store_chain().  */
-	      for (i = 0; i < group_size; i++)
+	      if (!slp)
 		{
-		  vec_oprnd = (*gvec_oprnds[i])[j];
-		  dr_chain[i] = vec_oprnd;
+		  /* We should have caught mismatched types earlier.  */
+		  gcc_assert (
+		    useless_type_conversion_p (vectype, TREE_TYPE (vec_oprnd)));
+		  for (i = 0; i < group_size; i++)
+		    {
+		      vec_oprnd = (*gvec_oprnds[i])[j];
+		      dr_chain[i] = vec_oprnd;
+		    }
 		}
 	      if (mask)
 		vec_mask = vec_masks[j];
@@ -8844,12 +8882,12 @@ vectorizable_store (vec_info *vinfo,
 
 	  if (costing_p)
 	    {
-	      n_adjacent_stores += vec_num;
+	      n_adjacent_stores += group_size;
 	      continue;
 	    }
 
 	  /* Get an array into which we can store the individual vectors.  */
-	  tree vec_array = create_vector_array (vectype, vec_num);
+	  tree vec_array = create_vector_array (vectype, group_size);
 
 	  /* Invalidate the current contents of VEC_ARRAY.  This should
 	     become an RTL clobber too, which prevents the vector registers
@@ -8857,9 +8895,19 @@ vectorizable_store (vec_info *vinfo,
 	  vect_clobber_variable (vinfo, stmt_info, gsi, vec_array);
 
 	  /* Store the individual vectors into the array.  */
-	  for (i = 0; i < vec_num; i++)
+	  for (i = 0; i < group_size; i++)
 	    {
-	      vec_oprnd = dr_chain[i];
+	      if (slp)
+		{
+		  slp_tree child;
+		  if (i == 0 || !mask_node)
+		    child = SLP_TREE_CHILDREN (slp_node)[i];
+		  else
+		    child = SLP_TREE_CHILDREN (slp_node)[i + 1];
+		  vec_oprnd = SLP_TREE_VEC_DEFS (child)[j];
+		}
+	      else
+		vec_oprnd = dr_chain[i];
 	      write_vector_array (vinfo, stmt_info, gsi, vec_oprnd, vec_array,
 				  i);
 	    }
@@ -8929,9 +8977,10 @@ vectorizable_store (vec_info *vinfo,
 
 	  /* Record that VEC_ARRAY is now dead.  */
 	  vect_clobber_variable (vinfo, stmt_info, gsi, vec_array);
-	  if (j == 0)
+	  if (j == 0 && !slp)
 	    *vec_stmt = new_stmt;
-	  STMT_VINFO_VEC_STMTS (stmt_info).safe_push (new_stmt);
+	  if (!slp)
+	    STMT_VINFO_VEC_STMTS (stmt_info).safe_push (new_stmt);
 	}
 
       if (costing_p)
@@ -10035,6 +10084,16 @@ vectorizable_load (vec_info *vinfo,
 			    &lanes_ifn))
     return false;
 
+  if (slp_node
+      && slp_node->ldst_lanes
+      && memory_access_type != VMAT_LOAD_STORE_LANES)
+    {
+      if (dump_enabled_p ())
+	dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+			 "discovered load-lane but cannot use it.\n");
+      return false;
+    }
+
   if (mask)
     {
       if (memory_access_type == VMAT_CONTIGUOUS)
@@ -10753,7 +10812,7 @@ vectorizable_load (vec_info *vinfo,
   else
     {
       if (memory_access_type == VMAT_LOAD_STORE_LANES)
-	aggr_type = build_array_type_nelts (elem_type, vec_num * nunits);
+	aggr_type = build_array_type_nelts (elem_type, group_size * nunits);
       else
 	aggr_type = vectype;
       bump = vect_get_data_ptr_increment (vinfo, gsi, dr_info, aggr_type,
@@ -10777,12 +10836,13 @@ vectorizable_load (vec_info *vinfo,
     {
       gcc_assert (alignment_support_scheme == dr_aligned
 		  || alignment_support_scheme == dr_unaligned_supported);
-      gcc_assert (grouped_load && !slp);
 
       unsigned int inside_cost = 0, prologue_cost = 0;
       /* For costing some adjacent vector loads, we'd like to cost with
 	 the total number of them once instead of cost each one by one. */
       unsigned int n_adjacent_loads = 0;
+      if (slp_node)
+	ncopies = slp_node->vec_stmts_size / group_size;
       for (j = 0; j < ncopies; j++)
 	{
 	  if (costing_p)
@@ -10833,7 +10893,7 @@ vectorizable_load (vec_info *vinfo,
 	  if (mask)
 	    vec_mask = vec_masks[j];
 
-	  tree vec_array = create_vector_array (vectype, vec_num);
+	  tree vec_array = create_vector_array (vectype, group_size);
 
 	  tree final_mask = NULL_TREE;
 	  tree final_len = NULL_TREE;
@@ -10896,24 +10956,31 @@ vectorizable_load (vec_info *vinfo,
 	  gimple_call_set_nothrow (call, true);
 	  vect_finish_stmt_generation (vinfo, stmt_info, call, gsi);
 
-	  dr_chain.create (vec_num);
+	  if (!slp)
+	    dr_chain.create (group_size);
 	  /* Extract each vector into an SSA_NAME.  */
-	  for (i = 0; i < vec_num; i++)
+	  for (unsigned i = 0; i < group_size; i++)
 	    {
 	      new_temp = read_vector_array (vinfo, stmt_info, gsi, scalar_dest,
 					    vec_array, i);
-	      dr_chain.quick_push (new_temp);
+	      if (slp)
+		slp_node->push_vec_def (new_temp);
+	      else
+		dr_chain.quick_push (new_temp);
 	    }
 
-	  /* Record the mapping between SSA_NAMEs and statements.  */
-	  vect_record_grouped_load_vectors (vinfo, stmt_info, dr_chain);
+	  if (!slp)
+	    /* Record the mapping between SSA_NAMEs and statements.  */
+	    vect_record_grouped_load_vectors (vinfo, stmt_info, dr_chain);
 
 	  /* Record that VEC_ARRAY is now dead.  */
 	  vect_clobber_variable (vinfo, stmt_info, gsi, vec_array);
 
-	  dr_chain.release ();
+	  if (!slp)
+	    dr_chain.release ();
 
-	  *vec_stmt = STMT_VINFO_VEC_STMTS (stmt_info)[0];
+	  if (!slp_node)
+	    *vec_stmt = STMT_VINFO_VEC_STMTS (stmt_info)[0];
 	}
 
       if (costing_p)
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index df6c8ad..699ae9e 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -222,6 +222,9 @@ struct _slp_tree {
   unsigned int lanes;
   /* The operation of this node.  */
   enum tree_code code;
+  /* Whether uses of this load or feeders of this store are suitable
+     for load/store-lanes.  */
+  bool ldst_lanes;
 
   int vertex;
 
@@ -2313,6 +2316,7 @@ extern bool supportable_indirect_convert_operation (code_helper,
 						    tree, tree,
 						    vec<std::pair<tree, tree_code> > *,
 						    tree = NULL_TREE);
+extern int compare_step_with_zero (vec_info *, stmt_vec_info);
 
 extern unsigned record_stmt_cost (stmt_vector_for_cost *, int,
 				  enum vect_cost_for_stmt, stmt_vec_info,