return pattern_stmt;
}
-/* Detect multiplication by constant which are postive or negatives of power 2,
- and convert them to shift patterns.
+/* Return true iff the target has a vector optab implementing the operation
+ CODE on type VECTYPE. */
- Mult with constants that are postive power of two.
- type a_t;
- type b_t
- S1: b_t = a_t * n
+static bool
+target_has_vecop_for_code (tree_code code, tree vectype)
+{
+ optab voptab = optab_for_tree_code (code, vectype, optab_vector);
+ return voptab
+ && optab_handler (voptab, TYPE_MODE (vectype)) != CODE_FOR_nothing;
+}
- or
+/* Verify that the target has optabs of VECTYPE to perform all the steps
+ needed by the multiplication-by-immediate synthesis algorithm described by
+ ALG and VAR. If SYNTH_SHIFT_P is true ensure that vector addition is
+ present. Return true iff the target supports all the steps. */
+
+static bool
+target_supports_mult_synth_alg (struct algorithm *alg, mult_variant var,
+ tree vectype, bool synth_shift_p)
+{
+ if (alg->op[0] != alg_zero && alg->op[0] != alg_m)
+ return false;
+
+ bool supports_vminus = target_has_vecop_for_code (MINUS_EXPR, vectype);
+ bool supports_vplus = target_has_vecop_for_code (PLUS_EXPR, vectype);
+
+ if (var == negate_variant
+ && !target_has_vecop_for_code (NEGATE_EXPR, vectype))
+ return false;
+
+ /* If we must synthesize shifts with additions make sure that vector
+ addition is available. */
+ if ((var == add_variant || synth_shift_p) && !supports_vplus)
+ return false;
+
+ for (int i = 1; i < alg->ops; i++)
+ {
+ switch (alg->op[i])
+ {
+ case alg_shift:
+ break;
+ case alg_add_t_m2:
+ case alg_add_t2_m:
+ case alg_add_factor:
+ if (!supports_vplus)
+ return false;
+ break;
+ case alg_sub_t_m2:
+ case alg_sub_t2_m:
+ case alg_sub_factor:
+ if (!supports_vminus)
+ return false;
+ break;
+ case alg_unknown:
+ case alg_m:
+ case alg_zero:
+ case alg_impossible:
+ return false;
+ default:
+ gcc_unreachable ();
+ }
+ }
+
+ return true;
+}
+
+/* Synthesize a left shift of OP by AMNT bits using a series of additions and
+ putting the final result in DEST. Append all statements but the last into
+ VINFO. Return the last statement. */
+
+static gimple *
+synth_lshift_by_additions (tree dest, tree op, HOST_WIDE_INT amnt,
+ stmt_vec_info vinfo)
+{
+ HOST_WIDE_INT i;
+ tree itype = TREE_TYPE (op);
+ tree prev_res = op;
+ gcc_assert (amnt >= 0);
+ for (i = 0; i < amnt; i++)
+ {
+ tree tmp_var = (i < amnt - 1) ? vect_recog_temp_ssa_var (itype, NULL)
+ : dest;
+ gimple *stmt
+ = gimple_build_assign (tmp_var, PLUS_EXPR, prev_res, prev_res);
+ prev_res = tmp_var;
+ if (i < amnt - 1)
+ append_pattern_def_seq (vinfo, stmt);
+ else
+ return stmt;
+ }
+ gcc_unreachable ();
+ return NULL;
+}
+
+/* Helper for vect_synth_mult_by_constant. Apply a binary operation
+ CODE to operands OP1 and OP2, creating a new temporary SSA var in
+ the process if necessary. Append the resulting assignment statements
+ to the sequence in STMT_VINFO. Return the SSA variable that holds the
+ result of the binary operation. If SYNTH_SHIFT_P is true synthesize
+ left shifts using additions. */
+
+static tree
+apply_binop_and_append_stmt (tree_code code, tree op1, tree op2,
+ stmt_vec_info stmt_vinfo, bool synth_shift_p)
+{
+ if (integer_zerop (op2)
+ && (code == LSHIFT_EXPR
+ || code == PLUS_EXPR))
+ {
+ gcc_assert (TREE_CODE (op1) == SSA_NAME);
+ return op1;
+ }
+
+ gimple *stmt;
+ tree itype = TREE_TYPE (op1);
+ tree tmp_var = vect_recog_temp_ssa_var (itype, NULL);
+
+ if (code == LSHIFT_EXPR
+ && synth_shift_p)
+ {
+ stmt = synth_lshift_by_additions (tmp_var, op1, TREE_INT_CST_LOW (op2),
+ stmt_vinfo);
+ append_pattern_def_seq (stmt_vinfo, stmt);
+ return tmp_var;
+ }
+
+ stmt = gimple_build_assign (tmp_var, code, op1, op2);
+ append_pattern_def_seq (stmt_vinfo, stmt);
+ return tmp_var;
+}
+
+/* Synthesize a multiplication of OP by an INTEGER_CST VAL using shifts
+ and simple arithmetic operations to be vectorized. Record the statements
+ produced in STMT_VINFO and return the last statement in the sequence or
+ NULL if it's not possible to synthesize such a multiplication.
+ This function mirrors the behavior of expand_mult_const in expmed.c but
+ works on tree-ssa form. */
+
+static gimple *
+vect_synth_mult_by_constant (tree op, tree val,
+ stmt_vec_info stmt_vinfo)
+{
+ tree itype = TREE_TYPE (op);
+ machine_mode mode = TYPE_MODE (itype);
+ struct algorithm alg;
+ mult_variant variant;
+ if (!tree_fits_shwi_p (val))
+ return NULL;
+
+ /* Multiplication synthesis by shifts, adds and subs can introduce
+ signed overflow where the original operation didn't. Perform the
+ operations on an unsigned type and cast back to avoid this.
+ In the future we may want to relax this for synthesis algorithms
+ that we can prove do not cause unexpected overflow. */
+ bool cast_to_unsigned_p = !TYPE_OVERFLOW_WRAPS (itype);
+
+ tree multtype = cast_to_unsigned_p ? unsigned_type_for (itype) : itype;
+
+ /* Targets that don't support vector shifts but support vector additions
+ can synthesize shifts that way. */
+ bool synth_shift_p = !vect_supportable_shift (LSHIFT_EXPR, multtype);
+
+ HOST_WIDE_INT hwval = tree_to_shwi (val);
+ /* Use MAX_COST here as we don't want to limit the sequence on rtx costs.
+ The vectorizer's benefit analysis will decide whether it's beneficial
+ to do this. */
+ bool possible = choose_mult_variant (mode, hwval, &alg,
+ &variant, MAX_COST);
+ if (!possible)
+ return NULL;
- Mult with constants that are negative power of two.
- S2: b_t = a_t * -n
+ tree vectype = get_vectype_for_scalar_type (multtype);
+
+ if (!vectype
+ || !target_supports_mult_synth_alg (&alg, variant,
+ vectype, synth_shift_p))
+ return NULL;
+
+ tree accumulator;
+
+ /* Clear out the sequence of statements so we can populate it below. */
+ STMT_VINFO_PATTERN_DEF_SEQ (stmt_vinfo) = NULL;
+ gimple *stmt = NULL;
+
+ if (cast_to_unsigned_p)
+ {
+ tree tmp_op = vect_recog_temp_ssa_var (multtype, NULL);
+ stmt = gimple_build_assign (tmp_op, CONVERT_EXPR, op);
+ append_pattern_def_seq (stmt_vinfo, stmt);
+ op = tmp_op;
+ }
+
+ if (alg.op[0] == alg_zero)
+ accumulator = build_int_cst (multtype, 0);
+ else
+ accumulator = op;
+
+ bool needs_fixup = (variant == negate_variant)
+ || (variant == add_variant);
+
+ for (int i = 1; i < alg.ops; i++)
+ {
+ tree shft_log = build_int_cst (multtype, alg.log[i]);
+ tree accum_tmp = vect_recog_temp_ssa_var (multtype, NULL);
+ tree tmp_var = NULL_TREE;
+
+ switch (alg.op[i])
+ {
+ case alg_shift:
+ if (synth_shift_p)
+ stmt
+ = synth_lshift_by_additions (accum_tmp, accumulator, alg.log[i],
+ stmt_vinfo);
+ else
+ stmt = gimple_build_assign (accum_tmp, LSHIFT_EXPR, accumulator,
+ shft_log);
+ break;
+ case alg_add_t_m2:
+ tmp_var
+ = apply_binop_and_append_stmt (LSHIFT_EXPR, op, shft_log,
+ stmt_vinfo, synth_shift_p);
+ stmt = gimple_build_assign (accum_tmp, PLUS_EXPR, accumulator,
+ tmp_var);
+ break;
+ case alg_sub_t_m2:
+ tmp_var = apply_binop_and_append_stmt (LSHIFT_EXPR, op,
+ shft_log, stmt_vinfo,
+ synth_shift_p);
+ /* In some algorithms the first step involves zeroing the
+ accumulator. If subtracting from such an accumulator
+ just emit the negation directly. */
+ if (integer_zerop (accumulator))
+ stmt = gimple_build_assign (accum_tmp, NEGATE_EXPR, tmp_var);
+ else
+ stmt = gimple_build_assign (accum_tmp, MINUS_EXPR, accumulator,
+ tmp_var);
+ break;
+ case alg_add_t2_m:
+ tmp_var
+ = apply_binop_and_append_stmt (LSHIFT_EXPR, accumulator, shft_log,
+ stmt_vinfo, synth_shift_p);
+ stmt = gimple_build_assign (accum_tmp, PLUS_EXPR, tmp_var, op);
+ break;
+ case alg_sub_t2_m:
+ tmp_var
+ = apply_binop_and_append_stmt (LSHIFT_EXPR, accumulator, shft_log,
+ stmt_vinfo, synth_shift_p);
+ stmt = gimple_build_assign (accum_tmp, MINUS_EXPR, tmp_var, op);
+ break;
+ case alg_add_factor:
+ tmp_var
+ = apply_binop_and_append_stmt (LSHIFT_EXPR, accumulator, shft_log,
+ stmt_vinfo, synth_shift_p);
+ stmt = gimple_build_assign (accum_tmp, PLUS_EXPR, accumulator,
+ tmp_var);
+ break;
+ case alg_sub_factor:
+ tmp_var
+ = apply_binop_and_append_stmt (LSHIFT_EXPR, accumulator, shft_log,
+ stmt_vinfo, synth_shift_p);
+ stmt = gimple_build_assign (accum_tmp, MINUS_EXPR, tmp_var,
+ accumulator);
+ break;
+ default:
+ gcc_unreachable ();
+ }
+ /* We don't want to append the last stmt in the sequence to stmt_vinfo
+ but rather return it directly. */
+
+ if ((i < alg.ops - 1) || needs_fixup || cast_to_unsigned_p)
+ append_pattern_def_seq (stmt_vinfo, stmt);
+ accumulator = accum_tmp;
+ }
+ if (variant == negate_variant)
+ {
+ tree accum_tmp = vect_recog_temp_ssa_var (multtype, NULL);
+ stmt = gimple_build_assign (accum_tmp, NEGATE_EXPR, accumulator);
+ accumulator = accum_tmp;
+ if (cast_to_unsigned_p)
+ append_pattern_def_seq (stmt_vinfo, stmt);
+ }
+ else if (variant == add_variant)
+ {
+ tree accum_tmp = vect_recog_temp_ssa_var (multtype, NULL);
+ stmt = gimple_build_assign (accum_tmp, PLUS_EXPR, accumulator, op);
+ accumulator = accum_tmp;
+ if (cast_to_unsigned_p)
+ append_pattern_def_seq (stmt_vinfo, stmt);
+ }
+ /* Move back to a signed if needed. */
+ if (cast_to_unsigned_p)
+ {
+ tree accum_tmp = vect_recog_temp_ssa_var (itype, NULL);
+ stmt = gimple_build_assign (accum_tmp, CONVERT_EXPR, accumulator);
+ }
+
+ return stmt;
+}
+
+/* Detect multiplication by constant and convert it into a sequence of
+ shifts and additions, subtractions, negations. We reuse the
+ choose_mult_variant algorithms from expmed.c
Input/Output:
STMTS: Contains a stmt from which the pattern search begins,
- i.e. the mult stmt. Convert the mult operation to LSHIFT if
- constant operand is a power of 2.
- type a_t, b_t
- S1': b_t = a_t << log2 (n)
-
- Convert the mult operation to LSHIFT and followed by a NEGATE
- if constant operand is a negative power of 2.
- type a_t, b_t, res_T;
- S2': b_t = a_t << log2 (n)
- S3': res_T = - (b_t)
+ i.e. the mult stmt.
Output:
* TYPE_OUT: The type of the output of this pattern.
- * Return value: A new stmt that will be used to replace the multiplication
- S1 or S2 stmt. */
+ * Return value: A new stmt that will be used to replace
+ the multiplication. */
static gimple *
vect_recog_mult_pattern (vec<gimple *> *stmts,
{
gimple *last_stmt = stmts->pop ();
tree oprnd0, oprnd1, vectype, itype;
- gimple *pattern_stmt, *def_stmt;
- optab optab;
+ gimple *pattern_stmt;
stmt_vec_info stmt_vinfo = vinfo_for_stmt (last_stmt);
- int power2_val, power2_neg_val;
- tree shift;
if (!is_gimple_assign (last_stmt))
return NULL;
/* If the target can handle vectorized multiplication natively,
don't attempt to optimize this. */
- optab = optab_for_tree_code (MULT_EXPR, vectype, optab_default);
- if (optab != unknown_optab)
+ optab mul_optab = optab_for_tree_code (MULT_EXPR, vectype, optab_default);
+ if (mul_optab != unknown_optab)
{
machine_mode vec_mode = TYPE_MODE (vectype);
- int icode = (int) optab_handler (optab, vec_mode);
+ int icode = (int) optab_handler (mul_optab, vec_mode);
if (icode != CODE_FOR_nothing)
- return NULL;
+ return NULL;
}
- /* If target cannot handle vector left shift then we cannot
- optimize and bail out. */
- optab = optab_for_tree_code (LSHIFT_EXPR, vectype, optab_vector);
- if (!optab
- || optab_handler (optab, TYPE_MODE (vectype)) == CODE_FOR_nothing)
- return NULL;
-
- power2_val = wi::exact_log2 (oprnd1);
- power2_neg_val = wi::exact_log2 (wi::neg (oprnd1));
-
- /* Handle constant operands that are postive or negative powers of 2. */
- if (power2_val != -1)
- {
- shift = build_int_cst (itype, power2_val);
- pattern_stmt
- = gimple_build_assign (vect_recog_temp_ssa_var (itype, NULL),
- LSHIFT_EXPR, oprnd0, shift);
- }
- else if (power2_neg_val != -1)
- {
- /* If the target cannot handle vector NEGATE then we cannot
- do the optimization. */
- optab = optab_for_tree_code (NEGATE_EXPR, vectype, optab_vector);
- if (!optab
- || optab_handler (optab, TYPE_MODE (vectype)) == CODE_FOR_nothing)
- return NULL;
-
- shift = build_int_cst (itype, power2_neg_val);
- def_stmt
- = gimple_build_assign (vect_recog_temp_ssa_var (itype, NULL),
- LSHIFT_EXPR, oprnd0, shift);
- new_pattern_def_seq (stmt_vinfo, def_stmt);
- pattern_stmt
- = gimple_build_assign (vect_recog_temp_ssa_var (itype, NULL),
- NEGATE_EXPR, gimple_assign_lhs (def_stmt));
- }
- else
+ pattern_stmt = vect_synth_mult_by_constant (oprnd0, oprnd1, stmt_vinfo);
+ if (!pattern_stmt)
return NULL;
/* Pattern detected. */
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