Split can_vec_perm_p into can_vec_perm_{var,const}_p

This patch splits can_vec_perm_p into two functions: can_vec_perm_var_p
for testing permute operations with variable selection vectors, and
can_vec_perm_const_p for testing permute operations with specific
constant selection vectors.  This means that we can pass the constant
selection vector by reference.

Constant permutes can still use a variable permute as a fallback.
A later patch adds a check to makre sure that we don't truncate the
vector indices when doing this.

However, have_whole_vector_shift checked:

  if (direct_optab_handler (vec_perm_const_optab, mode) == CODE_FOR_nothing)
    return false;

which had the effect of disallowing the fallback to variable permutes.
I'm not sure whether that was the intention or whether it was just
supposed to short-cut the loop on targets that don't support permutes.
(But then why bother?  The first check in the loop would fail and
we'd bail out straightaway.)

The patch adds a parameter for disallowing the fallback.  I think it
makes sense to do this for the following code in the VEC_PERM_EXPR
folder:

	  /* Some targets are deficient and fail to expand a single
	     argument permutation while still allowing an equivalent
	     2-argument version.  */
	  if (need_mask_canon && arg2 == op2
	      && !can_vec_perm_p (TYPE_MODE (type), false, &sel)
	      && can_vec_perm_p (TYPE_MODE (type), false, &sel2))

since it's really testing whether the expand_vec_perm_const code expects
a particular form.

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

gcc/
	* optabs-query.h (can_vec_perm_p): Delete.
	(can_vec_perm_var_p, can_vec_perm_const_p): Declare.
	* optabs-query.c (can_vec_perm_p): Split into...
	(can_vec_perm_var_p, can_vec_perm_const_p): ...these two functions.
	(can_mult_highpart_p): Use can_vec_perm_const_p to test whether a
	particular selector is valid.
	* tree-ssa-forwprop.c (simplify_vector_constructor): Likewise.
	* tree-vect-data-refs.c (vect_grouped_store_supported): Likewise.
	(vect_grouped_load_supported): Likewise.
	(vect_shift_permute_load_chain): Likewise.
	* tree-vect-slp.c (vect_build_slp_tree_1): Likewise.
	(vect_transform_slp_perm_load): Likewise.
	* tree-vect-stmts.c (perm_mask_for_reverse): Likewise.
	(vectorizable_bswap): Likewise.
	(vect_gen_perm_mask_checked): Likewise.
	* fold-const.c (fold_ternary_loc): Likewise.  Don't take
	implementations of variable permutation vectors into account
	when deciding which selector to use.
	* tree-vect-loop.c (have_whole_vector_shift): Don't check whether
	vec_perm_const_optab is supported; instead use can_vec_perm_const_p
	with a false third argument.
	* tree-vect-generic.c (lower_vec_perm): Use can_vec_perm_const_p
	to test whether the constant selector is valid and can_vec_perm_var_p
	to test whether a variable selector is valid.

From-SVN: r256091
This commit is contained in:
Richard Sandiford 2018-01-02 18:26:06 +00:00 committed by Richard Sandiford
parent 4aae3cb355
commit 7ac7e2868d
10 changed files with 122 additions and 68 deletions

View File

@ -1,3 +1,30 @@
2018-01-02 Richard Sandiford <richard.sandiford@linaro.org>
* optabs-query.h (can_vec_perm_p): Delete.
(can_vec_perm_var_p, can_vec_perm_const_p): Declare.
* optabs-query.c (can_vec_perm_p): Split into...
(can_vec_perm_var_p, can_vec_perm_const_p): ...these two functions.
(can_mult_highpart_p): Use can_vec_perm_const_p to test whether a
particular selector is valid.
* tree-ssa-forwprop.c (simplify_vector_constructor): Likewise.
* tree-vect-data-refs.c (vect_grouped_store_supported): Likewise.
(vect_grouped_load_supported): Likewise.
(vect_shift_permute_load_chain): Likewise.
* tree-vect-slp.c (vect_build_slp_tree_1): Likewise.
(vect_transform_slp_perm_load): Likewise.
* tree-vect-stmts.c (perm_mask_for_reverse): Likewise.
(vectorizable_bswap): Likewise.
(vect_gen_perm_mask_checked): Likewise.
* fold-const.c (fold_ternary_loc): Likewise. Don't take
implementations of variable permutation vectors into account
when deciding which selector to use.
* tree-vect-loop.c (have_whole_vector_shift): Don't check whether
vec_perm_const_optab is supported; instead use can_vec_perm_const_p
with a false third argument.
* tree-vect-generic.c (lower_vec_perm): Use can_vec_perm_const_p
to test whether the constant selector is valid and can_vec_perm_var_p
to test whether a variable selector is valid.
2018-01-02 Richard Sandiford <richard.sandiford@linaro.org>
* optabs-query.h (can_vec_perm_p): Take a const vec_perm_indices *.

View File

@ -11778,8 +11778,8 @@ fold_ternary_loc (location_t loc, enum tree_code code, tree type,
argument permutation while still allowing an equivalent
2-argument version. */
if (need_mask_canon && arg2 == op2
&& !can_vec_perm_p (TYPE_MODE (type), false, &sel)
&& can_vec_perm_p (TYPE_MODE (type), false, &sel2))
&& !can_vec_perm_const_p (TYPE_MODE (type), sel, false)
&& can_vec_perm_const_p (TYPE_MODE (type), sel2, false))
{
need_mask_canon = need_mask_canon2;
sel = sel2;

View File

@ -361,60 +361,88 @@ qimode_for_vec_perm (machine_mode mode)
return opt_machine_mode ();
}
/* Return true if VEC_PERM_EXPR of arbitrary input vectors can be
expanded using SIMD extensions of the CPU. SEL may be NULL, which
stands for an unknown constant. Note that additional permutations
representing whole-vector shifts may also be handled via the vec_shr
optab, but only where the second input vector is entirely constant
zeroes; this case is not dealt with here. */
/* Return true if VEC_PERM_EXPRs with variable selector operands can be
expanded using SIMD extensions of the CPU. MODE is the mode of the
vectors being permuted. */
bool
can_vec_perm_p (machine_mode mode, bool variable, const vec_perm_indices *sel)
can_vec_perm_var_p (machine_mode mode)
{
machine_mode qimode;
/* If the target doesn't implement a vector mode for the vector type,
then no operations are supported. */
if (!VECTOR_MODE_P (mode))
return false;
if (!variable)
{
if (direct_optab_handler (vec_perm_const_optab, mode) != CODE_FOR_nothing
&& (sel == NULL
|| targetm.vectorize.vec_perm_const_ok == NULL
|| targetm.vectorize.vec_perm_const_ok (mode, *sel)))
return true;
}
if (direct_optab_handler (vec_perm_optab, mode) != CODE_FOR_nothing)
return true;
/* We allow fallback to a QI vector mode, and adjust the mask. */
machine_mode qimode;
if (!qimode_for_vec_perm (mode).exists (&qimode))
return false;
/* ??? For completeness, we ought to check the QImode version of
vec_perm_const_optab. But all users of this implicit lowering
feature implement the variable vec_perm_optab. */
if (direct_optab_handler (vec_perm_optab, qimode) == CODE_FOR_nothing)
return false;
/* In order to support the lowering of variable permutations,
we need to support shifts and adds. */
if (variable)
{
if (GET_MODE_UNIT_SIZE (mode) > 2
&& optab_handler (ashl_optab, mode) == CODE_FOR_nothing
&& optab_handler (vashl_optab, mode) == CODE_FOR_nothing)
return false;
if (optab_handler (add_optab, qimode) == CODE_FOR_nothing)
return false;
}
if (GET_MODE_UNIT_SIZE (mode) > 2
&& optab_handler (ashl_optab, mode) == CODE_FOR_nothing
&& optab_handler (vashl_optab, mode) == CODE_FOR_nothing)
return false;
if (optab_handler (add_optab, qimode) == CODE_FOR_nothing)
return false;
return true;
}
/* Return true if the target directly supports VEC_PERM_EXPRs on vectors
of mode MODE using the selector SEL. ALLOW_VARIABLE_P is true if it
is acceptable to force the selector into a register and use a variable
permute (if the target supports that).
Note that additional permutations representing whole-vector shifts may
also be handled via the vec_shr optab, but only where the second input
vector is entirely constant zeroes; this case is not dealt with here. */
bool
can_vec_perm_const_p (machine_mode mode, const vec_perm_indices &sel,
bool allow_variable_p)
{
/* If the target doesn't implement a vector mode for the vector type,
then no operations are supported. */
if (!VECTOR_MODE_P (mode))
return false;
/* It's probably cheaper to test for the variable case first. */
if (allow_variable_p)
{
if (direct_optab_handler (vec_perm_optab, mode) != CODE_FOR_nothing)
return true;
/* Unlike can_vec_perm_var_p, we don't need to test for optabs
related computing the QImode selector, since that happens at
compile time. */
machine_mode qimode;
if (qimode_for_vec_perm (mode).exists (&qimode)
&& direct_optab_handler (vec_perm_optab, qimode) != CODE_FOR_nothing)
return true;
}
if (direct_optab_handler (vec_perm_const_optab, mode) != CODE_FOR_nothing)
{
if (targetm.vectorize.vec_perm_const_ok == NULL
|| targetm.vectorize.vec_perm_const_ok (mode, sel))
return true;
/* ??? For completeness, we ought to check the QImode version of
vec_perm_const_optab. But all users of this implicit lowering
feature implement the variable vec_perm_optab. */
}
return false;
}
/* Find a widening optab even if it doesn't widen as much as we want.
E.g. if from_mode is HImode, and to_mode is DImode, and there is no
direct HI->SI insn, then return SI->DI, if that exists. */
@ -472,7 +500,7 @@ can_mult_highpart_p (machine_mode mode, bool uns_p)
sel.quick_push (!BYTES_BIG_ENDIAN
+ (i & ~1)
+ ((i & 1) ? nunits : 0));
if (can_vec_perm_p (mode, false, &sel))
if (can_vec_perm_const_p (mode, sel))
return 2;
}
}
@ -486,7 +514,7 @@ can_mult_highpart_p (machine_mode mode, bool uns_p)
auto_vec_perm_indices sel (nunits);
for (i = 0; i < nunits; ++i)
sel.quick_push (2 * i + (BYTES_BIG_ENDIAN ? 0 : 1));
if (can_vec_perm_p (mode, false, &sel))
if (can_vec_perm_const_p (mode, sel))
return 3;
}
}

View File

@ -175,7 +175,9 @@ enum insn_code can_float_p (machine_mode, machine_mode, int);
enum insn_code can_fix_p (machine_mode, machine_mode, int, bool *);
bool can_conditionally_move_p (machine_mode mode);
opt_machine_mode qimode_for_vec_perm (machine_mode);
bool can_vec_perm_p (machine_mode, bool, const vec_perm_indices *);
bool can_vec_perm_var_p (machine_mode);
bool can_vec_perm_const_p (machine_mode, const vec_perm_indices &,
bool = true);
/* Find a widening optab even if it doesn't widen as much as we want. */
#define find_widening_optab_handler(A, B, C) \
find_widening_optab_handler_and_mode (A, B, C, NULL)

View File

@ -2108,7 +2108,7 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
{
tree mask_type;
if (!can_vec_perm_p (TYPE_MODE (type), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (type), sel))
return false;
mask_type
= build_vector_type (build_nonstandard_integer_type (elem_size, 1),

View File

@ -4600,11 +4600,11 @@ vect_grouped_store_supported (tree vectype, unsigned HOST_WIDE_INT count)
if (3 * i + nelt2 < nelt)
sel[3 * i + nelt2] = 0;
}
if (!can_vec_perm_p (mode, false, &sel))
if (!can_vec_perm_const_p (mode, sel))
{
if (dump_enabled_p ())
dump_printf (MSG_MISSED_OPTIMIZATION,
"permutaion op not supported by target.\n");
"permutation op not supported by target.\n");
return false;
}
@ -4617,11 +4617,11 @@ vect_grouped_store_supported (tree vectype, unsigned HOST_WIDE_INT count)
if (3 * i + nelt2 < nelt)
sel[3 * i + nelt2] = nelt + j2++;
}
if (!can_vec_perm_p (mode, false, &sel))
if (!can_vec_perm_const_p (mode, sel))
{
if (dump_enabled_p ())
dump_printf (MSG_MISSED_OPTIMIZATION,
"permutaion op not supported by target.\n");
"permutation op not supported by target.\n");
return false;
}
}
@ -4637,11 +4637,11 @@ vect_grouped_store_supported (tree vectype, unsigned HOST_WIDE_INT count)
sel[i * 2] = i;
sel[i * 2 + 1] = i + nelt;
}
if (can_vec_perm_p (mode, false, &sel))
if (can_vec_perm_const_p (mode, sel))
{
for (i = 0; i < nelt; i++)
sel[i] += nelt / 2;
if (can_vec_perm_p (mode, false, &sel))
if (can_vec_perm_const_p (mode, sel))
return true;
}
}
@ -5179,7 +5179,7 @@ vect_grouped_load_supported (tree vectype, bool single_element_p,
sel[i] = 3 * i + k;
else
sel[i] = 0;
if (!can_vec_perm_p (mode, false, &sel))
if (!can_vec_perm_const_p (mode, sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5192,7 +5192,7 @@ vect_grouped_load_supported (tree vectype, bool single_element_p,
sel[i] = i;
else
sel[i] = nelt + ((nelt + k) % 3) + 3 * (j++);
if (!can_vec_perm_p (mode, false, &sel))
if (!can_vec_perm_const_p (mode, sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5209,11 +5209,11 @@ vect_grouped_load_supported (tree vectype, bool single_element_p,
gcc_assert (pow2p_hwi (count));
for (i = 0; i < nelt; i++)
sel[i] = i * 2;
if (can_vec_perm_p (mode, false, &sel))
if (can_vec_perm_const_p (mode, sel))
{
for (i = 0; i < nelt; i++)
sel[i] = i * 2 + 1;
if (can_vec_perm_p (mode, false, &sel))
if (can_vec_perm_const_p (mode, sel))
return true;
}
}
@ -5540,7 +5540,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
sel[i] = i * 2;
for (i = 0; i < nelt / 2; ++i)
sel[nelt / 2 + i] = i * 2 + 1;
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5554,7 +5554,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
sel[i] = i * 2 + 1;
for (i = 0; i < nelt / 2; ++i)
sel[nelt / 2 + i] = i * 2;
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5568,7 +5568,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
For vector length 8 it is {4 5 6 7 8 9 10 11}. */
for (i = 0; i < nelt; i++)
sel[i] = nelt / 2 + i;
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5583,7 +5583,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
sel[i] = i;
for (i = nelt / 2; i < nelt; i++)
sel[i] = nelt + i;
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5646,7 +5646,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
sel[i] = 3 * k + (l % 3);
k++;
}
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5660,7 +5660,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
For vector length 8 it is {6 7 8 9 10 11 12 13}. */
for (i = 0; i < nelt; i++)
sel[i] = 2 * (nelt / 3) + (nelt % 3) + i;
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5673,7 +5673,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
For vector length 8 it is {5 6 7 8 9 10 11 12}. */
for (i = 0; i < nelt; i++)
sel[i] = 2 * (nelt / 3) + 1 + i;
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5686,7 +5686,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
For vector length 8 it is {3 4 5 6 7 8 9 10}. */
for (i = 0; i < nelt; i++)
sel[i] = (nelt / 3) + (nelt % 3) / 2 + i;
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
@ -5699,7 +5699,7 @@ vect_shift_permute_load_chain (vec<tree> dr_chain,
For vector length 8 it is {5 6 7 8 9 10 11 12}. */
for (i = 0; i < nelt; i++)
sel[i] = 2 * (nelt / 3) + (nelt % 3) / 2 + i;
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,

View File

@ -1306,7 +1306,7 @@ lower_vec_perm (gimple_stmt_iterator *gsi)
sel_int.quick_push (TREE_INT_CST_LOW (VECTOR_CST_ELT (mask, i))
& (2 * elements - 1));
if (can_vec_perm_p (TYPE_MODE (vect_type), false, &sel_int))
if (can_vec_perm_const_p (TYPE_MODE (vect_type), sel_int))
{
gimple_assign_set_rhs3 (stmt, mask);
update_stmt (stmt);
@ -1337,7 +1337,7 @@ lower_vec_perm (gimple_stmt_iterator *gsi)
}
}
}
else if (can_vec_perm_p (TYPE_MODE (vect_type), true, NULL))
else if (can_vec_perm_var_p (TYPE_MODE (vect_type)))
return;
warning_at (loc, OPT_Wvector_operation_performance,

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@ -3729,9 +3729,6 @@ have_whole_vector_shift (machine_mode mode)
if (optab_handler (vec_shr_optab, mode) != CODE_FOR_nothing)
return true;
if (direct_optab_handler (vec_perm_const_optab, mode) == CODE_FOR_nothing)
return false;
unsigned int i, nelt = GET_MODE_NUNITS (mode);
auto_vec_perm_indices sel (nelt);
@ -3739,7 +3736,7 @@ have_whole_vector_shift (machine_mode mode)
{
sel.truncate (0);
calc_vec_perm_mask_for_shift (i, nelt, &sel);
if (!can_vec_perm_p (mode, false, &sel))
if (!can_vec_perm_const_p (mode, sel, false))
return false;
}
return true;

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@ -901,7 +901,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
elt += count;
sel.quick_push (elt);
}
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
{
for (i = 0; i < group_size; ++i)
if (gimple_assign_rhs_code (stmts[i]) == alt_stmt_code)
@ -3646,7 +3646,7 @@ vect_transform_slp_perm_load (slp_tree node, vec<tree> dr_chain,
if (index == nunits)
{
if (! noop_p
&& ! can_vec_perm_p (mode, false, &mask))
&& ! can_vec_perm_const_p (mode, mask))
{
if (dump_enabled_p ())
{

View File

@ -1720,7 +1720,7 @@ perm_mask_for_reverse (tree vectype)
for (i = 0; i < nunits; ++i)
sel.quick_push (nunits - 1 - i);
if (!can_vec_perm_p (TYPE_MODE (vectype), false, &sel))
if (!can_vec_perm_const_p (TYPE_MODE (vectype), sel))
return NULL_TREE;
return vect_gen_perm_mask_checked (vectype, sel);
}
@ -2502,7 +2502,7 @@ vectorizable_bswap (gimple *stmt, gimple_stmt_iterator *gsi,
for (unsigned j = 0; j < word_bytes; ++j)
elts.quick_push ((i + 1) * word_bytes - j - 1);
if (! can_vec_perm_p (TYPE_MODE (char_vectype), false, &elts))
if (!can_vec_perm_const_p (TYPE_MODE (char_vectype), elts))
return false;
if (! vec_stmt)
@ -6519,7 +6519,7 @@ vectorizable_store (gimple *stmt, gimple_stmt_iterator *gsi, gimple **vec_stmt,
/* Given a vector type VECTYPE, turns permutation SEL into the equivalent
VECTOR_CST mask. No checks are made that the target platform supports the
mask, so callers may wish to test can_vec_perm_p separately, or use
mask, so callers may wish to test can_vec_perm_const_p separately, or use
vect_gen_perm_mask_checked. */
tree
@ -6540,13 +6540,13 @@ vect_gen_perm_mask_any (tree vectype, const vec_perm_indices &sel)
return mask_elts.build ();
}
/* Checked version of vect_gen_perm_mask_any. Asserts can_vec_perm_p,
/* Checked version of vect_gen_perm_mask_any. Asserts can_vec_perm_const_p,
i.e. that the target supports the pattern _for arbitrary input vectors_. */
tree
vect_gen_perm_mask_checked (tree vectype, const vec_perm_indices &sel)
{
gcc_assert (can_vec_perm_p (TYPE_MODE (vectype), false, &sel));
gcc_assert (can_vec_perm_const_p (TYPE_MODE (vectype), sel));
return vect_gen_perm_mask_any (vectype, sel);
}