Make vec_perm_indices use new vector encoding

This patch changes vec_perm_indices from a plain vec<> to a class
that stores a canonicalized permutation, using the same encoding
as for VECTOR_CSTs.  This means that vec_perm_indices now carries
information about the number of vectors being permuted (currently
always 1 or 2) and the number of elements in each input vector.

A new vec_perm_builder class is used to actually build up the vector,
like tree_vector_builder does for trees.  vec_perm_indices is the
completed representation, a bit like VECTOR_CST is for trees.

The patch just does a mechanical conversion of the code to
vec_perm_builder: a later patch uses explicit encodings where possible.

The point of all this is that it makes the representation suitable
for variable-length vectors.  It's no longer necessary for the
underlying vec<>s to store every element explicitly.

In int-vector-builder.h, "using the same encoding as tree and rtx constants"
describes the endpoint -- adding the rtx encoding comes later.

2018-01-02  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* int-vector-builder.h: New file.
	* vec-perm-indices.h: Include int-vector-builder.h.
	(vec_perm_indices): Redefine as an int_vector_builder.
	(auto_vec_perm_indices): Delete.
	(vec_perm_builder): Redefine as a stand-alone class.
	(vec_perm_indices::vec_perm_indices): New function.
	(vec_perm_indices::clamp): Likewise.
	* vec-perm-indices.c: Include fold-const.h and tree-vector-builder.h.
	(vec_perm_indices::new_vector): New function.
	(vec_perm_indices::new_expanded_vector): Update for new
	vec_perm_indices class.
	(vec_perm_indices::rotate_inputs): New function.
	(vec_perm_indices::all_in_range_p): Operate directly on the
	encoded form, without computing elided elements.
	(tree_to_vec_perm_builder): Operate directly on the VECTOR_CST
	encoding.  Update for new vec_perm_indices class.
	* optabs.c (expand_vec_perm_const): Create a vec_perm_indices for
	the given vec_perm_builder.
	(expand_vec_perm_var): Update vec_perm_builder constructor.
	(expand_mult_highpart): Use vec_perm_builder instead of
	auto_vec_perm_indices.
	* optabs-query.c (can_mult_highpart_p): Use vec_perm_builder and
	vec_perm_indices instead of auto_vec_perm_indices.  Use a single
	or double series encoding as appropriate.
	* fold-const.c (fold_ternary_loc): Use vec_perm_builder and
	vec_perm_indices instead of auto_vec_perm_indices.
	* tree-ssa-forwprop.c (simplify_vector_constructor): Likewise.
	* tree-vect-data-refs.c (vect_grouped_store_supported): Likewise.
	(vect_permute_store_chain): Likewise.
	(vect_grouped_load_supported): Likewise.
	(vect_permute_load_chain): Likewise.
	(vect_shift_permute_load_chain): Likewise.
	* tree-vect-slp.c (vect_build_slp_tree_1): Likewise.
	(vect_transform_slp_perm_load): Likewise.
	(vect_schedule_slp_instance): Likewise.
	* tree-vect-stmts.c (perm_mask_for_reverse): Likewise.
	(vectorizable_mask_load_store): Likewise.
	(vectorizable_bswap): Likewise.
	(vectorizable_store): Likewise.
	(vectorizable_load): Likewise.
	* tree-vect-generic.c (lower_vec_perm): Use vec_perm_builder and
	vec_perm_indices instead of auto_vec_perm_indices.  Use
	tree_to_vec_perm_builder to read the vector from a tree.
	* tree-vect-loop.c (calc_vec_perm_mask_for_shift): Take a
	vec_perm_builder instead of a vec_perm_indices.
	(have_whole_vector_shift): Use vec_perm_builder and
	vec_perm_indices instead of auto_vec_perm_indices.  Leave the
	truncation to calc_vec_perm_mask_for_shift.
	(vect_create_epilog_for_reduction): Likewise.
	* config/aarch64/aarch64.c (expand_vec_perm_d::perm): Change
	from auto_vec_perm_indices to vec_perm_indices.
	(aarch64_expand_vec_perm_const_1): Use rotate_inputs on d.perm
	instead of changing individual elements.
	(aarch64_vectorize_vec_perm_const): Use new_vector to install
	the vector in d.perm.
	* config/arm/arm.c (expand_vec_perm_d::perm): Change
	from auto_vec_perm_indices to vec_perm_indices.
	(arm_expand_vec_perm_const_1): Use rotate_inputs on d.perm
	instead of changing individual elements.
	(arm_vectorize_vec_perm_const): Use new_vector to install
	the vector in d.perm.
	* config/powerpcspe/powerpcspe.c (rs6000_expand_extract_even):
	Update vec_perm_builder constructor.
	(rs6000_expand_interleave): Likewise.
	* config/rs6000/rs6000.c (rs6000_expand_extract_even): Likewise.
	(rs6000_expand_interleave): Likewise.

From-SVN: r256095

4 files changed, 12 insertions, 21 deletions

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 05b82bc..93e9d9f9 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -13252,7 +13252,7 @@ aarch64_split_combinev16qi (rtx operands[3])
 struct expand_vec_perm_d
 {
   rtx target, op0, op1;
-  auto_vec_perm_indices perm;
+  vec_perm_indices perm;
   machine_mode vmode;
   bool one_vector_p;
   bool testing_p;
@@ -13642,10 +13642,7 @@ aarch64_expand_vec_perm_const_1 (struct expand_vec_perm_d *d)
   unsigned int nelt = d->perm.length ();
   if (d->perm[0] >= nelt)
     {
-      gcc_assert (nelt == (nelt & -nelt));
-      for (unsigned int i = 0; i < nelt; ++i)
-	d->perm[i] ^= nelt; /* Keep the same index, but in the other vector.  */
-
+      d->perm.rotate_inputs (1);
       std::swap (d->op0, d->op1);
     }
 
@@ -13685,12 +13682,10 @@ aarch64_vectorize_vec_perm_const (machine_mode vmode, rtx target, rtx op0,
 
   /* Calculate whether all elements are in one vector.  */
   unsigned int nelt = sel.length ();
-  d.perm.reserve (nelt);
   for (i = which = 0; i < nelt; ++i)
     {
       unsigned int ei = sel[i] & (2 * nelt - 1);
       which |= (ei < nelt ? 1 : 2);
-      d.perm.quick_push (ei);
     }
 
   switch (which)
@@ -13709,8 +13704,6 @@ aarch64_vectorize_vec_perm_const (machine_mode vmode, rtx target, rtx op0,
 	 input vector.  */
       /* Fall Through.  */
     case 2:
-      for (i = 0; i < nelt; ++i)
-	d.perm[i] &= nelt - 1;
       d.op0 = op1;
       d.one_vector_p = true;
       break;
@@ -13721,6 +13714,8 @@ aarch64_vectorize_vec_perm_const (machine_mode vmode, rtx target, rtx op0,
       break;
     }
 
+  d.perm.new_vector (sel.encoding (), d.one_vector_p ? 1 : 2, nelt);
+
   if (!d.testing_p)
     return aarch64_expand_vec_perm_const_1 (&d);
 
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 2173d95..11e35ad 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -28854,7 +28854,7 @@ arm_split_atomic_op (enum rtx_code code, rtx old_out, rtx new_out, rtx mem,
 struct expand_vec_perm_d
 {
   rtx target, op0, op1;
-  auto_vec_perm_indices perm;
+  vec_perm_indices perm;
   machine_mode vmode;
   bool one_vector_p;
   bool testing_p;
@@ -29362,9 +29362,7 @@ arm_expand_vec_perm_const_1 (struct expand_vec_perm_d *d)
   unsigned int nelt = d->perm.length ();
   if (d->perm[0] >= nelt)
     {
-      for (unsigned int i = 0; i < nelt; ++i)
-	d->perm[i] = (d->perm[i] + nelt) & (2 * nelt - 1);
-
+      d->perm.rotate_inputs (1);
       std::swap (d->op0, d->op1);
     }
 
@@ -29404,12 +29402,10 @@ arm_vectorize_vec_perm_const (machine_mode vmode, rtx target, rtx op0, rtx op1,
   d.testing_p = !target;
 
   nelt = GET_MODE_NUNITS (d.vmode);
-  d.perm.reserve (nelt);
   for (i = which = 0; i < nelt; ++i)
     {
       int ei = sel[i] & (2 * nelt - 1);
       which |= (ei < nelt ? 1 : 2);
-      d.perm.quick_push (ei);
     }
 
   switch (which)
@@ -29428,8 +29424,6 @@ arm_vectorize_vec_perm_const (machine_mode vmode, rtx target, rtx op0, rtx op1,
 	 input vector.  */
       /* FALLTHRU */
     case 2:
-      for (i = 0; i < nelt; ++i)
-        d.perm[i] &= nelt - 1;
       d.op0 = op1;
       d.one_vector_p = true;
       break;
@@ -29440,6 +29434,8 @@ arm_vectorize_vec_perm_const (machine_mode vmode, rtx target, rtx op0, rtx op1,
       break;
     }
 
+  d.perm.new_vector (sel.encoding (), d.one_vector_p ? 1 : 2, nelt);
+
   if (d.testing_p)
     return arm_expand_vec_perm_const_1 (&d);
 
diff --git a/gcc/config/powerpcspe/powerpcspe.c b/gcc/config/powerpcspe/powerpcspe.c
index 9133125..520f2e1 100644
--- a/gcc/config/powerpcspe/powerpcspe.c
+++ b/gcc/config/powerpcspe/powerpcspe.c
@@ -38782,7 +38782,7 @@ rs6000_expand_extract_even (rtx target, rtx op0, rtx op1)
 {
   machine_mode vmode = GET_MODE (target);
   unsigned i, nelt = GET_MODE_NUNITS (vmode);
-  vec_perm_builder perm (nelt);
+  vec_perm_builder perm (nelt, nelt, 1);
 
   for (i = 0; i < nelt; i++)
     perm.quick_push (i * 2);
@@ -38797,7 +38797,7 @@ rs6000_expand_interleave (rtx target, rtx op0, rtx op1, bool highp)
 {
   machine_mode vmode = GET_MODE (target);
   unsigned i, high, nelt = GET_MODE_NUNITS (vmode);
-  vec_perm_builder perm (nelt);
+  vec_perm_builder perm (nelt, nelt, 1);
 
   high = (highp ? 0 : nelt / 2);
   for (i = 0; i < nelt / 2; i++)
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 7d10b44..2e4af41 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -36042,7 +36042,7 @@ rs6000_expand_extract_even (rtx target, rtx op0, rtx op1)
 {
   machine_mode vmode = GET_MODE (target);
   unsigned i, nelt = GET_MODE_NUNITS (vmode);
-  vec_perm_builder perm (nelt);
+  vec_perm_builder perm (nelt, nelt, 1);
 
   for (i = 0; i < nelt; i++)
     perm.quick_push (i * 2);
@@ -36057,7 +36057,7 @@ rs6000_expand_interleave (rtx target, rtx op0, rtx op1, bool highp)
 {
   machine_mode vmode = GET_MODE (target);
   unsigned i, high, nelt = GET_MODE_NUNITS (vmode);
-  vec_perm_builder perm (nelt);
+  vec_perm_builder perm (nelt, nelt, 1);
 
   high = (highp ? 0 : nelt / 2);
   for (i = 0; i < nelt / 2; i++)