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[PATCH] Strength reduction preliminaries
- From: "William J. Schmidt" <wschmidt at linux dot vnet dot ibm dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: rguenther at suse dot de, bergner at vnet dot ibm dot com
- Date: Thu, 21 Jun 2012 11:01:03 -0500
- Subject: [PATCH] Strength reduction preliminaries
As promised, this breaks out the changes to the IVOPTS cost model and
the added function in double-int.c. Please let me know if you would
rather see me attempt to consolidate the IVOPTS logic into expmed.c per
Richard H's suggestion.
I ran into a glitch with multiply_by_const_cost. The original code
declared a static htab_t in the function and allocated it on demand.
When I tried adding a second one in the same manner, I ran into a
locking problem in the memory management library code during a call to
delete_htab. The original implementation seemed a bit dicey to me
anyway, so I changed this to explicitly allocate and deallocate the hash
tables on (entry to/exit from) IVOPTS.
This reduces the scope of the hash table from a compilation unit to each
individual function. If it's preferred to maintain compilation unit
scope, then the initialization/finalization of the htabs can be pushed
out to do_compile. But I doubt it's worth that.
Bootstrapped and tested on powerpc64-unknown-linux-gnu with no new
regressions. Ok for trunk?
Thanks,
Bill
2012-06-21 Bill Schmidt <wschmidt@linux.ibm.com>
* double-int.c (double_int_multiple_of): New function.
* double-int.h (double_int_multiple_of): New decl.
* tree-ssa-loop-ivopts.c (add_cost, zero_cost): Remove undefs.
(mbc_entry_hash): New forward decl.
(mbc_entry_eq): Likewise.
(zero_cost): Change to no_cost.
(mult_costs): New static var.
(tree_ssa_iv_optimize_init): Initialize mult_costs.
(add_cost): Change to add_regs_cost; distinguish costs by speed.
(multiply_regs_cost): New function.
(add_const_cost): Likewise.
(extend_or_trunc_reg_cost): Likewise.
(negate_reg_cost): Likewise.
(multiply_by_cost): Change to multiply_by_const_cost; distinguish
costs by speed.
(get_address_cost): Change add_cost to add_regs_cost; change
multiply_by_cost to multiply_by_const_cost.
(force_expr_to_var_cost): Change zero_cost to no_cost; change
add_cost to add_regs_cost; change multiply_by_cost to
multiply_by_const_cost.
(split_cost): Change zero_cost to no_cost.
(ptr_difference_cost): Likewise.
(difference_cost): Change zero_cost to no_cost; change multiply_by_cost
to multiply_by_const_cost.
(get_computation_cost_at): Change add_cost to add_regs_cost; change
multiply_by_cost to multiply_by_const_cost.
(determine_use_iv_cost_generic): Change zero_cost to no_cost.
(determine_iv_cost): Change add_cost to add_regs_cost.
(iv_ca_new): Change zero_cost to no_cost.
(tree_ssa_iv_optimize_finalize): Release storage for mult_costs.
* tree-ssa-address.c (most_expensive_mult_to_index): Change
multiply_by_cost to multiply_by_const_cost.
* tree-flow.h (multiply_by_cost): Change to multiply_by_const_cost.
(add_regs_cost): New decl.
(multiply_regs_cost): Likewise.
(add_const_cost): Likewise.
(extend_or_trunc_reg_cost): Likewise.
(negate_reg_cost): Likewise.
Index: gcc/double-int.c
===================================================================
--- gcc/double-int.c (revision 188839)
+++ gcc/double-int.c (working copy)
@@ -865,6 +865,26 @@ double_int_umod (double_int a, double_int b, unsig
return double_int_mod (a, b, true, code);
}
+/* Return TRUE iff PRODUCT is an integral multiple of FACTOR, and return
+ the multiple in *MULTIPLE. Otherwise return FALSE and leave *MULTIPLE
+ unchanged. */
+
+bool
+double_int_multiple_of (double_int product, double_int factor,
+ bool unsigned_p, double_int *multiple)
+{
+ double_int remainder;
+ double_int quotient = double_int_divmod (product, factor, unsigned_p,
+ TRUNC_DIV_EXPR, &remainder);
+ if (double_int_zero_p (remainder))
+ {
+ *multiple = quotient;
+ return true;
+ }
+
+ return false;
+}
+
/* Set BITPOS bit in A. */
double_int
double_int_setbit (double_int a, unsigned bitpos)
Index: gcc/double-int.h
===================================================================
--- gcc/double-int.h (revision 188839)
+++ gcc/double-int.h (working copy)
@@ -150,6 +150,8 @@ double_int double_int_divmod (double_int, double_i
double_int double_int_sdivmod (double_int, double_int, unsigned, double_int *);
double_int double_int_udivmod (double_int, double_int, unsigned, double_int *);
+bool double_int_multiple_of (double_int, double_int, bool, double_int *);
+
double_int double_int_setbit (double_int, unsigned);
int double_int_ctz (double_int);
Index: gcc/tree-ssa-loop-ivopts.c
===================================================================
--- gcc/tree-ssa-loop-ivopts.c (revision 188839)
+++ gcc/tree-ssa-loop-ivopts.c (working copy)
@@ -89,13 +89,11 @@ along with GCC; see the file COPYING3. If not see
#include "target.h"
#include "tree-inline.h"
#include "tree-ssa-propagate.h"
-
-/* FIXME: add_cost and zero_cost defined in exprmed.h conflict with local uses.
- */
#include "expmed.h"
-#undef add_cost
-#undef zero_cost
+static hashval_t mbc_entry_hash (const void *);
+static int mbc_entry_eq (const void*, const void *);
+
/* FIXME: Expressions are expanded to RTL in this pass to determine the
cost of different addressing modes. This should be moved to a TBD
interface between the GIMPLE and RTL worlds. */
@@ -162,7 +160,7 @@ typedef struct
complex expressions and addressing modes). */
} comp_cost;
-static const comp_cost zero_cost = {0, 0};
+static const comp_cost no_cost = {0, 0};
static const comp_cost infinite_cost = {INFTY, INFTY};
/* The candidate - cost pair. */
@@ -386,6 +384,9 @@ struct iv_ca_delta
static VEC(tree,heap) *decl_rtl_to_reset;
+/* Cached costs for multiplies by constants. */
+static htab_t mult_costs[2];
+
static comp_cost force_expr_to_var_cost (tree, bool);
/* Number of uses recorded in DATA. */
@@ -869,6 +870,9 @@ tree_ssa_iv_optimize_init (struct ivopts_data *dat
htab_inv_expr_eq, free);
data->inv_expr_id = 0;
decl_rtl_to_reset = VEC_alloc (tree, heap, 20);
+
+ mult_costs[0] = htab_create (100, mbc_entry_hash, mbc_entry_eq, free);
+ mult_costs[1] = htab_create (100, mbc_entry_hash, mbc_entry_eq, free);
}
/* Returns a memory object to that EXPR points. In case we are able to
@@ -3057,16 +3061,19 @@ adjust_setup_cost (struct ivopts_data *data, unsig
/* Returns cost of addition in MODE. */
-static unsigned
-add_cost (enum machine_mode mode, bool speed)
+unsigned
+add_regs_cost (enum machine_mode mode, bool speed)
{
- static unsigned costs[NUM_MACHINE_MODES];
+ static unsigned costs[NUM_MACHINE_MODES][2];
rtx seq;
unsigned cost;
- if (costs[mode])
- return costs[mode];
+ if (speed)
+ speed = 1;
+ if (costs[mode][speed])
+ return costs[mode][speed];
+
start_sequence ();
force_operand (gen_rtx_fmt_ee (PLUS, mode,
gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 1),
@@ -3079,7 +3086,7 @@ adjust_setup_cost (struct ivopts_data *data, unsig
if (!cost)
cost = 1;
- costs[mode] = cost;
+ costs[mode][speed] = cost;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Addition in %s costs %d\n",
@@ -3087,6 +3094,160 @@ adjust_setup_cost (struct ivopts_data *data, unsig
return cost;
}
+/* Returns cost of multiplication in MODE. */
+
+unsigned
+multiply_regs_cost (enum machine_mode mode, bool speed)
+{
+ static unsigned costs[NUM_MACHINE_MODES][2];
+ rtx seq;
+ unsigned cost;
+
+ if (speed)
+ speed = 1;
+
+ if (costs[mode][speed])
+ return costs[mode][speed];
+
+ start_sequence ();
+ force_operand (gen_rtx_fmt_ee (MULT, mode,
+ gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 1),
+ gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 2)),
+ NULL_RTX);
+ seq = get_insns ();
+ end_sequence ();
+
+ cost = seq_cost (seq, speed);
+ if (!cost)
+ cost = 1;
+
+ costs[mode][speed] = cost;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Multiplication in %s costs %d\n",
+ GET_MODE_NAME (mode), cost);
+ return cost;
+}
+
+/* Returns cost of addition with a constant in MODE. */
+
+unsigned
+add_const_cost (enum machine_mode mode, bool speed)
+{
+ static unsigned costs[NUM_MACHINE_MODES][2];
+ rtx seq;
+ unsigned cost;
+
+ if (speed)
+ speed = 1;
+
+ if (costs[mode][speed])
+ return costs[mode][speed];
+
+ /* Arbitrarily generate insns for x + 2, as the exact constant
+ shouldn't matter. */
+ start_sequence ();
+ force_operand (gen_rtx_fmt_ee (PLUS, mode,
+ gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 1),
+ gen_int_mode (2, mode)),
+ NULL_RTX);
+ seq = get_insns ();
+ end_sequence ();
+
+ cost = seq_cost (seq, speed);
+ if (!cost)
+ cost = 1;
+
+ costs[mode][speed] = cost;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Addition to constant in %s costs %d\n",
+ GET_MODE_NAME (mode), cost);
+ return cost;
+}
+
+/* Returns cost of extend or truncate in MODE. */
+
+unsigned
+extend_or_trunc_reg_cost (tree type_to, tree type_from, bool speed)
+{
+ static unsigned costs[NUM_MACHINE_MODES][NUM_MACHINE_MODES][2];
+ rtx seq;
+ unsigned cost;
+ enum machine_mode mode_to = TYPE_MODE (type_to);
+ enum machine_mode mode_from = TYPE_MODE (type_from);
+ tree size_to = TYPE_SIZE (type_to);
+ tree size_from = TYPE_SIZE (type_from);
+ enum rtx_code code;
+
+ gcc_assert (TREE_CODE (size_to) == INTEGER_CST
+ && TREE_CODE (size_from) == INTEGER_CST);
+
+ if (speed)
+ speed = 1;
+
+ if (costs[mode_to][mode_from][speed])
+ return costs[mode_to][mode_from][speed];
+
+ if (tree_int_cst_lt (size_to, size_from))
+ code = TRUNCATE;
+ else if (TYPE_UNSIGNED (type_to))
+ code = ZERO_EXTEND;
+ else
+ code = SIGN_EXTEND;
+
+ start_sequence ();
+ gen_rtx_fmt_e (code, mode_to,
+ gen_raw_REG (mode_from, LAST_VIRTUAL_REGISTER + 1));
+ seq = get_insns ();
+ end_sequence ();
+
+ cost = seq_cost (seq, speed);
+ if (!cost)
+ cost = 1;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Conversion from %s to %s costs %d\n",
+ GET_MODE_NAME (mode_to), GET_MODE_NAME (mode_from), cost);
+
+ costs[mode_to][mode_from][speed] = cost;
+ return cost;
+}
+
+/* Returns cost of negation in MODE. */
+
+unsigned
+negate_reg_cost (enum machine_mode mode, bool speed)
+{
+ static unsigned costs[NUM_MACHINE_MODES][2];
+ rtx seq;
+ unsigned cost;
+
+ if (speed)
+ speed = 1;
+
+ if (costs[mode][speed])
+ return costs[mode][speed];
+
+ start_sequence ();
+ force_operand (gen_rtx_fmt_e (NEG, mode,
+ gen_raw_REG (mode, LAST_VIRTUAL_REGISTER + 1)),
+ NULL_RTX);
+ seq = get_insns ();
+ end_sequence ();
+
+ cost = seq_cost (seq, speed);
+ if (!cost)
+ cost = 1;
+
+ costs[mode][speed] = cost;
+
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "Negation in %s costs %d\n",
+ GET_MODE_NAME (mode), cost);
+ return cost;
+}
+
/* Entry in a hashtable of already known costs for multiplication. */
struct mbc_entry
{
@@ -3120,19 +3281,20 @@ mbc_entry_eq (const void *entry1, const void *entr
/* Returns cost of multiplication by constant CST in MODE. */
unsigned
-multiply_by_cost (HOST_WIDE_INT cst, enum machine_mode mode, bool speed)
+multiply_by_const_cost (HOST_WIDE_INT cst, enum machine_mode mode, bool speed)
{
- static htab_t costs;
struct mbc_entry **cached, act;
rtx seq;
unsigned cost;
- if (!costs)
- costs = htab_create (100, mbc_entry_hash, mbc_entry_eq, free);
+ if (speed)
+ speed = 1;
act.mode = mode;
act.cst = cst;
- cached = (struct mbc_entry **) htab_find_slot (costs, &act, INSERT);
+ cached = (struct mbc_entry **)
+ htab_find_slot (mult_costs[speed], &act, INSERT);
+
if (*cached)
return (*cached)->cost;
@@ -3418,7 +3580,7 @@ get_address_cost (bool symbol_present, bool var_pr
If VAR_PRESENT is true, try whether the mode with
SYMBOL_PRESENT = false is cheaper even with cost of addition, and
if this is the case, use it. */
- add_c = add_cost (address_mode, speed);
+ add_c = add_regs_cost (address_mode, speed);
for (i = 0; i < 8; i++)
{
var_p = i & 1;
@@ -3499,10 +3661,10 @@ get_address_cost (bool symbol_present, bool var_pr
&& multiplier_allowed_in_address_p (ratio, mem_mode, as));
if (ratio != 1 && !ratio_p)
- cost += multiply_by_cost (ratio, address_mode, speed);
+ cost += multiply_by_const_cost (ratio, address_mode, speed);
if (s_offset && !offset_p && !symbol_present)
- cost += add_cost (address_mode, speed);
+ cost += add_regs_cost (address_mode, speed);
if (may_autoinc)
*may_autoinc = autoinc;
@@ -3601,7 +3763,7 @@ force_expr_to_var_cost (tree expr, bool speed)
STRIP_NOPS (expr);
if (SSA_VAR_P (expr))
- return zero_cost;
+ return no_cost;
if (is_gimple_min_invariant (expr))
{
@@ -3633,12 +3795,12 @@ force_expr_to_var_cost (tree expr, bool speed)
STRIP_NOPS (op1);
if (is_gimple_val (op0))
- cost0 = zero_cost;
+ cost0 = no_cost;
else
cost0 = force_expr_to_var_cost (op0, speed);
if (is_gimple_val (op1))
- cost1 = zero_cost;
+ cost1 = no_cost;
else
cost1 = force_expr_to_var_cost (op1, speed);
@@ -3650,11 +3812,11 @@ force_expr_to_var_cost (tree expr, bool speed)
op1 = NULL_TREE;
if (is_gimple_val (op0))
- cost0 = zero_cost;
+ cost0 = no_cost;
else
cost0 = force_expr_to_var_cost (op0, speed);
- cost1 = zero_cost;
+ cost1 = no_cost;
break;
default:
@@ -3669,7 +3831,7 @@ force_expr_to_var_cost (tree expr, bool speed)
case PLUS_EXPR:
case MINUS_EXPR:
case NEGATE_EXPR:
- cost = new_cost (add_cost (mode, speed), 0);
+ cost = new_cost (add_regs_cost (mode, speed), 0);
if (TREE_CODE (expr) != NEGATE_EXPR)
{
tree mult = NULL_TREE;
@@ -3689,9 +3851,11 @@ force_expr_to_var_cost (tree expr, bool speed)
case MULT_EXPR:
if (cst_and_fits_in_hwi (op0))
- cost = new_cost (multiply_by_cost (int_cst_value (op0), mode, speed), 0);
+ cost = new_cost (multiply_by_const_cost (int_cst_value (op0),
+ mode, speed), 0);
else if (cst_and_fits_in_hwi (op1))
- cost = new_cost (multiply_by_cost (int_cst_value (op1), mode, speed), 0);
+ cost = new_cost (multiply_by_const_cost (int_cst_value (op1),
+ mode, speed), 0);
else
return new_cost (target_spill_cost [speed], 0);
break;
@@ -3766,12 +3930,12 @@ split_address_cost (struct ivopts_data *data,
{
*symbol_present = true;
*var_present = false;
- return zero_cost;
+ return no_cost;
}
*symbol_present = false;
*var_present = true;
- return zero_cost;
+ return no_cost;
}
/* Estimates cost of expressing difference of addresses E1 - E2 as
@@ -3796,7 +3960,7 @@ ptr_difference_cost (struct ivopts_data *data,
*offset += diff;
*symbol_present = false;
*var_present = false;
- return zero_cost;
+ return no_cost;
}
if (integer_zerop (e2))
@@ -3846,7 +4010,7 @@ difference_cost (struct ivopts_data *data,
if (operand_equal_p (e1, e2, 0))
{
*var_present = false;
- return zero_cost;
+ return no_cost;
}
*var_present = true;
@@ -3857,7 +4021,7 @@ difference_cost (struct ivopts_data *data,
if (integer_zerop (e1))
{
comp_cost cost = force_var_cost (data, e2, depends_on);
- cost.cost += multiply_by_cost (-1, mode, data->speed);
+ cost.cost += multiply_by_const_cost (-1, mode, data->speed);
return cost;
}
@@ -4168,7 +4332,7 @@ get_computation_cost_at (struct ivopts_data *data,
&symbol_present, &var_present,
&offset, depends_on));
cost.cost /= avg_loop_niter (data->current_loop);
- cost.cost += add_cost (TYPE_MODE (ctype), data->speed);
+ cost.cost += add_regs_cost (TYPE_MODE (ctype), data->speed);
}
if (inv_expr_id)
@@ -4201,7 +4365,7 @@ get_computation_cost_at (struct ivopts_data *data,
if (!symbol_present && !var_present && !offset)
{
if (ratio != 1)
- cost.cost += multiply_by_cost (ratio, TYPE_MODE (ctype), speed);
+ cost.cost += multiply_by_const_cost (ratio, TYPE_MODE (ctype), speed);
return cost;
}
@@ -4209,18 +4373,18 @@ get_computation_cost_at (struct ivopts_data *data,
are added once to the variable, if present. */
if (var_present && (symbol_present || offset))
cost.cost += adjust_setup_cost (data,
- add_cost (TYPE_MODE (ctype), speed));
+ add_regs_cost (TYPE_MODE (ctype), speed));
/* Having offset does not affect runtime cost in case it is added to
symbol, but it increases complexity. */
if (offset)
cost.complexity++;
- cost.cost += add_cost (TYPE_MODE (ctype), speed);
+ cost.cost += add_regs_cost (TYPE_MODE (ctype), speed);
aratio = ratio > 0 ? ratio : -ratio;
if (aratio != 1)
- cost.cost += multiply_by_cost (aratio, TYPE_MODE (ctype), speed);
+ cost.cost += multiply_by_const_cost (aratio, TYPE_MODE (ctype), speed);
return cost;
fallback:
@@ -4277,7 +4441,7 @@ determine_use_iv_cost_generic (struct ivopts_data
if (cand->pos == IP_ORIGINAL
&& cand->incremented_at == use->stmt)
{
- set_use_iv_cost (data, use, cand, zero_cost, NULL, NULL_TREE,
+ set_use_iv_cost (data, use, cand, no_cost, NULL, NULL_TREE,
ERROR_MARK, -1);
return true;
}
@@ -5066,7 +5230,7 @@ determine_iv_cost (struct ivopts_data *data, struc
or a const set. */
if (cost_base.cost == 0)
cost_base.cost = COSTS_N_INSNS (1);
- cost_step = add_cost (TYPE_MODE (TREE_TYPE (base)), data->speed);
+ cost_step = add_regs_cost (TYPE_MODE (TREE_TYPE (base)), data->speed);
cost = cost_step + adjust_setup_cost (data, cost_base.cost);
@@ -5561,10 +5725,10 @@ iv_ca_new (struct ivopts_data *data)
nw->cands = BITMAP_ALLOC (NULL);
nw->n_cands = 0;
nw->n_regs = 0;
- nw->cand_use_cost = zero_cost;
+ nw->cand_use_cost = no_cost;
nw->cand_cost = 0;
nw->n_invariant_uses = XCNEWVEC (unsigned, data->max_inv_id + 1);
- nw->cost = zero_cost;
+ nw->cost = no_cost;
nw->used_inv_expr = XCNEWVEC (unsigned, data->inv_expr_id + 1);
nw->num_used_inv_expr = 0;
@@ -6638,6 +6802,8 @@ tree_ssa_iv_optimize_finalize (struct ivopts_data
VEC_free (iv_use_p, heap, data->iv_uses);
VEC_free (iv_cand_p, heap, data->iv_candidates);
htab_delete (data->inv_expr_tab);
+ htab_delete (mult_costs[0]);
+ htab_delete (mult_costs[1]);
}
/* Returns true if the loop body BODY includes any function calls. */
Index: gcc/tree-ssa-address.c
===================================================================
--- gcc/tree-ssa-address.c (revision 188839)
+++ gcc/tree-ssa-address.c (working copy)
@@ -556,7 +556,7 @@ most_expensive_mult_to_index (tree type, struct me
|| !multiplier_allowed_in_address_p (coef, TYPE_MODE (type), as))
continue;
- acost = multiply_by_cost (coef, address_mode, speed);
+ acost = multiply_by_const_cost (coef, address_mode, speed);
if (acost > best_mult_cost)
{
Index: gcc/tree-flow.h
===================================================================
--- gcc/tree-flow.h (revision 188839)
+++ gcc/tree-flow.h (working copy)
@@ -810,7 +810,12 @@ bool expr_invariant_in_loop_p (struct loop *, tree
bool stmt_invariant_in_loop_p (struct loop *, gimple);
bool multiplier_allowed_in_address_p (HOST_WIDE_INT, enum machine_mode,
addr_space_t);
-unsigned multiply_by_cost (HOST_WIDE_INT, enum machine_mode, bool);
+unsigned multiply_by_const_cost (HOST_WIDE_INT, enum machine_mode, bool);
+unsigned add_regs_cost (enum machine_mode, bool);
+unsigned multiply_regs_cost (enum machine_mode, bool);
+unsigned add_const_cost (enum machine_mode, bool);
+unsigned extend_or_trunc_reg_cost (tree, tree, bool);
+unsigned negate_reg_cost (enum machine_mode, bool);
bool may_be_nonaddressable_p (tree expr);
/* In tree-ssa-threadupdate.c. */