typedef struct operand_entry
{
unsigned int rank;
+ int id;
tree op;
} *operand_entry_t;
static alloc_pool operand_entry_pool;
+/* This is used to assign a unique ID to each struct operand_entry
+ so that qsort results are identical on different hosts. */
+static int next_operand_entry_id;
/* Starting rank number for a given basic block, so that we can rank
operations using unmovable instructions in that BB based on the bb
to fold when added/multiplied//whatever are put next to each
other. Since all constants have rank 0, order them by type. */
if (oeb->rank == 0 && oea->rank == 0)
- return constant_type (oeb->op) - constant_type (oea->op);
+ {
+ if (constant_type (oeb->op) != constant_type (oea->op))
+ return constant_type (oeb->op) - constant_type (oea->op);
+ else
+ /* To make sorting result stable, we use unique IDs to determine
+ order. */
+ return oeb->id - oea->id;
+ }
/* Lastly, make sure the versions that are the same go next to each
other. We use SSA_NAME_VERSION because it's stable. */
if ((oeb->rank - oea->rank == 0)
&& TREE_CODE (oea->op) == SSA_NAME
&& TREE_CODE (oeb->op) == SSA_NAME)
- return SSA_NAME_VERSION (oeb->op) - SSA_NAME_VERSION (oea->op);
+ {
+ if (SSA_NAME_VERSION (oeb->op) != SSA_NAME_VERSION (oea->op))
+ return SSA_NAME_VERSION (oeb->op) - SSA_NAME_VERSION (oea->op);
+ else
+ return oeb->id - oea->id;
+ }
- return oeb->rank - oea->rank;
+ if (oeb->rank != oea->rank)
+ return oeb->rank - oea->rank;
+ else
+ return oeb->id - oea->id;
}
/* Add an operand entry to *OPS for the tree operand OP. */
oe->op = op;
oe->rank = get_rank (op);
+ oe->id = next_operand_entry_id++;
VEC_safe_push (operand_entry_t, heap, *ops, oe);
}
return false;
}
+static VEC(tree, heap) *plus_negates;
+
/* If OPCODE is PLUS_EXPR, CURR->OP is really a negate expression,
look in OPS for a corresponding positive operation to cancel it
out. If we find one, remove the other from OPS, replace
}
}
+ /* CURR->OP is a negate expr in a plus expr: save it for later
+ inspection in repropagate_negates(). */
+ VEC_safe_push (tree, heap, plus_negates, curr->op);
+
return false;
}
/* Structure for tracking and counting operands. */
typedef struct oecount_s {
int cnt;
+ int id;
enum tree_code oecode;
tree op;
} oecount;
{
const oecount *c1 = (const oecount *)p1;
const oecount *c2 = (const oecount *)p2;
- return c1->cnt - c2->cnt;
+ if (c1->cnt != c2->cnt)
+ return c1->cnt - c2->cnt;
+ else
+ /* If counts are identical, use unique IDs to stabilize qsort. */
+ return c1->id - c2->id;
}
/* Walks the linear chain with result *DEF searching for an operation
VEC (operand_entry_t, heap) **subops;
htab_t ctable;
bool changed = false;
+ int next_oecount_id = 0;
if (length <= 1
|| opcode != PLUS_EXPR)
size_t idx;
c.oecode = oecode;
c.cnt = 1;
+ c.id = next_oecount_id++;
c.op = oe1->op;
VEC_safe_push (oecount, heap, cvec, &c);
idx = VEC_length (oecount, cvec) + 41;
return NULL;
}
-static VEC(tree, heap) *broken_up_subtracts;
-
/* Recursively negate the value of TONEGATE, and return the SSA_NAME
representing the negated value. Insertions of any necessary
instructions go before GSI.
tonegate = fold_build1 (NEGATE_EXPR, TREE_TYPE (tonegate), tonegate);
resultofnegate = force_gimple_operand_gsi (gsi, tonegate, true,
NULL_TREE, true, GSI_SAME_STMT);
- VEC_safe_push (tree, heap, broken_up_subtracts, resultofnegate);
return resultofnegate;
}
unsigned int i = 0;
tree negate;
- for (i = 0; VEC_iterate (tree, broken_up_subtracts, i, negate); i++)
+ for (i = 0; VEC_iterate (tree, plus_negates, i, negate); i++)
{
gimple user = get_single_immediate_use (negate);
+ if (!user || !is_gimple_assign (user))
+ continue;
+
/* The negate operand can be either operand of a PLUS_EXPR
(it can be the LHS if the RHS is a constant for example).
Force the negate operand to the RHS of the PLUS_EXPR, then
transform the PLUS_EXPR into a MINUS_EXPR. */
- if (user
- && is_gimple_assign (user)
- && gimple_assign_rhs_code (user) == PLUS_EXPR)
+ if (gimple_assign_rhs_code (user) == PLUS_EXPR)
{
/* If the negated operand appears on the LHS of the
PLUS_EXPR, exchange the operands of the PLUS_EXPR
update_stmt (user);
}
}
+ else if (gimple_assign_rhs_code (user) == MINUS_EXPR)
+ {
+ if (gimple_assign_rhs1 (user) == negate)
+ {
+ /* We have
+ x = -a
+ y = x - b
+ which we transform into
+ x = a + b
+ y = -x .
+ This pushes down the negate which we possibly can merge
+ into some other operation, hence insert it into the
+ plus_negates vector. */
+ gimple feed = SSA_NAME_DEF_STMT (negate);
+ tree a = gimple_assign_rhs1 (feed);
+ tree rhs2 = gimple_assign_rhs2 (user);
+ gimple_stmt_iterator gsi = gsi_for_stmt (feed), gsi2;
+ gimple_replace_lhs (feed, negate);
+ gimple_assign_set_rhs_with_ops (&gsi, PLUS_EXPR, a, rhs2);
+ update_stmt (gsi_stmt (gsi));
+ gsi2 = gsi_for_stmt (user);
+ gimple_assign_set_rhs_with_ops (&gsi2, NEGATE_EXPR, negate, NULL);
+ update_stmt (gsi_stmt (gsi2));
+ gsi_move_before (&gsi, &gsi2);
+ VEC_safe_push (tree, heap, plus_negates,
+ gimple_assign_lhs (gsi_stmt (gsi2)));
+ }
+ else
+ {
+ /* Transform "x = -a; y = b - x" into "y = b + a", getting
+ rid of one operation. */
+ gimple feed = SSA_NAME_DEF_STMT (negate);
+ tree a = gimple_assign_rhs1 (feed);
+ tree rhs1 = gimple_assign_rhs1 (user);
+ gimple_stmt_iterator gsi = gsi_for_stmt (user);
+ gimple_assign_set_rhs_with_ops (&gsi, PLUS_EXPR, rhs1, a);
+ update_stmt (gsi_stmt (gsi));
+ }
+ }
}
}
+/* Returns true if OP is of a type for which we can do reassociation.
+ That is for integral or non-saturating fixed-point types, and for
+ floating point type when associative-math is enabled. */
+
+static bool
+can_reassociate_p (tree op)
+{
+ tree type = TREE_TYPE (op);
+ if (INTEGRAL_TYPE_P (type)
+ || NON_SAT_FIXED_POINT_TYPE_P (type)
+ || (flag_associative_math && SCALAR_FLOAT_TYPE_P (type)))
+ return true;
+ return false;
+}
+
/* Break up subtract operations in block BB.
We do this top down because we don't know whether the subtract is
gimple stmt = gsi_stmt (gsi);
gimple_set_visited (stmt, false);
+ if (!is_gimple_assign (stmt)
+ || !can_reassociate_p (gimple_assign_lhs (stmt)))
+ continue;
+
/* Look for simple gimple subtract operations. */
- if (is_gimple_assign (stmt)
- && gimple_assign_rhs_code (stmt) == MINUS_EXPR)
+ if (gimple_assign_rhs_code (stmt) == MINUS_EXPR)
{
- tree lhs = gimple_assign_lhs (stmt);
- tree rhs1 = gimple_assign_rhs1 (stmt);
- tree rhs2 = gimple_assign_rhs2 (stmt);
-
- /* If associative-math we can do reassociation for
- non-integral types. Or, we can do reassociation for
- non-saturating fixed-point types. */
- if ((!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- || !INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
- || !INTEGRAL_TYPE_P (TREE_TYPE (rhs2)))
- && (!SCALAR_FLOAT_TYPE_P (TREE_TYPE (lhs))
- || !SCALAR_FLOAT_TYPE_P (TREE_TYPE(rhs1))
- || !SCALAR_FLOAT_TYPE_P (TREE_TYPE(rhs2))
- || !flag_associative_math)
- && (!NON_SAT_FIXED_POINT_TYPE_P (TREE_TYPE (lhs))
- || !NON_SAT_FIXED_POINT_TYPE_P (TREE_TYPE(rhs1))
- || !NON_SAT_FIXED_POINT_TYPE_P (TREE_TYPE(rhs2))))
+ if (!can_reassociate_p (gimple_assign_rhs1 (stmt))
+ || !can_reassociate_p (gimple_assign_rhs2 (stmt)))
continue;
/* Check for a subtract used only in an addition. If this
if (should_break_up_subtract (stmt))
break_up_subtract (stmt, &gsi);
}
+ else if (gimple_assign_rhs_code (stmt) == NEGATE_EXPR
+ && can_reassociate_p (gimple_assign_rhs1 (stmt)))
+ VEC_safe_push (tree, heap, plus_negates, gimple_assign_lhs (stmt));
}
for (son = first_dom_son (CDI_DOMINATORS, bb);
son;
rhs1 = gimple_assign_rhs1 (stmt);
rhs2 = gimple_assign_rhs2 (stmt);
- /* If associative-math we can do reassociation for
- non-integral types. Or, we can do reassociation for
- non-saturating fixed-point types. */
- if ((!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- || !INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
- || !INTEGRAL_TYPE_P (TREE_TYPE (rhs2)))
- && (!SCALAR_FLOAT_TYPE_P (TREE_TYPE (lhs))
- || !SCALAR_FLOAT_TYPE_P (TREE_TYPE(rhs1))
- || !SCALAR_FLOAT_TYPE_P (TREE_TYPE(rhs2))
- || !flag_associative_math)
- && (!NON_SAT_FIXED_POINT_TYPE_P (TREE_TYPE (lhs))
- || !NON_SAT_FIXED_POINT_TYPE_P (TREE_TYPE(rhs1))
- || !NON_SAT_FIXED_POINT_TYPE_P (TREE_TYPE(rhs2))))
+ if (!can_reassociate_p (lhs)
+ || !can_reassociate_p (rhs1)
+ || !can_reassociate_p (rhs2))
continue;
if (associative_tree_code (rhs_code))
operand_entry_pool = create_alloc_pool ("operand entry pool",
sizeof (struct operand_entry), 30);
+ next_operand_entry_id = 0;
/* Reverse RPO (Reverse Post Order) will give us something where
deeper loops come later. */
free (bbs);
calculate_dominance_info (CDI_POST_DOMINATORS);
- broken_up_subtracts = NULL;
+ plus_negates = NULL;
}
/* Cleanup after the reassociation pass, and print stats if
pointer_map_destroy (operand_rank);
free_alloc_pool (operand_entry_pool);
free (bb_rank);
- VEC_free (tree, heap, broken_up_subtracts);
+ VEC_free (tree, heap, plus_negates);
free_dominance_info (CDI_POST_DOMINATORS);
loop_optimizer_finalize ();
}
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