/* Loop invariant motion.
- Copyright (C) 2003 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
#include "params.h"
#include "tree-pass.h"
#include "flags.h"
+#include "real.h"
+
+/* TODO: Support for predicated code motion. I.e.
+
+ while (1)
+ {
+ if (cond)
+ {
+ a = inv;
+ something;
+ }
+ }
+
+ Where COND and INV are is invariants, but evaluating INV may trap or be
+ invalid from some other reason if !COND. This may be transformed to
+
+ if (cond)
+ a = inv;
+ while (1)
+ {
+ if (cond)
+ something;
+ } */
/* A type for the list of statements that have to be moved in order to be able
to hoist an invariant computation. */
MAX_LOOP loop. */
};
-#define LIM_DATA(STMT) ((struct lim_aux_data *) (stmt_ann (STMT)->common.aux))
+#define LIM_DATA(STMT) (TREE_CODE (STMT) == PHI_NODE \
+ ? NULL \
+ : (struct lim_aux_data *) (stmt_ann (STMT)->aux))
/* Description of a memory reference for store motion. */
block will be executed. */
#define ALWAYS_EXECUTED_IN(BB) ((struct loop *) (BB)->aux)
-/* Maximum uid in the statement in the function. */
+static unsigned max_stmt_uid; /* Maximal uid of a statement. Uids to phi
+ nodes are assigned using the versions of
+ ssa names they define. */
-static unsigned max_uid;
+/* Returns uid of statement STMT. */
+
+static unsigned
+get_stmt_uid (tree stmt)
+{
+ if (TREE_CODE (stmt) == PHI_NODE)
+ return SSA_NAME_VERSION (PHI_RESULT (stmt)) + max_stmt_uid;
+
+ return stmt_ann (stmt)->uid;
+}
/* Calls CBCK for each index in memory reference ADDR_P. There are two
kinds situations handled; in each of these cases, the memory reference
bool
for_each_index (tree *addr_p, bool (*cbck) (tree, tree *, void *), void *data)
{
- tree *nxt;
+ tree *nxt, *idx;
for (; ; addr_p = nxt)
{
case SSA_NAME:
return cbck (*addr_p, addr_p, data);
+ case MISALIGNED_INDIRECT_REF:
+ case ALIGN_INDIRECT_REF:
case INDIRECT_REF:
nxt = &TREE_OPERAND (*addr_p, 0);
return cbck (*addr_p, nxt, data);
case BIT_FIELD_REF:
- case COMPONENT_REF:
case VIEW_CONVERT_EXPR:
case ARRAY_RANGE_REF:
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ nxt = &TREE_OPERAND (*addr_p, 0);
+ break;
+
+ case COMPONENT_REF:
+ /* If the component has varying offset, it behaves like index
+ as well. */
+ idx = &TREE_OPERAND (*addr_p, 2);
+ if (*idx
+ && !cbck (*addr_p, idx, data))
+ return false;
+
nxt = &TREE_OPERAND (*addr_p, 0);
break;
return true;
default:
- abort ();
+ gcc_unreachable ();
}
}
}
{
/* If we perform unswitching, force the operands of the invariant
condition to be moved out of the loop. */
- get_stmt_operands (stmt);
-
return MOVE_POSSIBLE;
}
if (stmt_ends_bb_p (stmt))
return MOVE_IMPOSSIBLE;
- get_stmt_operands (stmt);
-
if (stmt_ann (stmt)->has_volatile_ops)
return MOVE_IMPOSSIBLE;
|| tree_could_trap_p (rhs))
return MOVE_PRESERVE_EXECUTION;
+ if (get_call_expr_in (stmt))
+ {
+ /* While pure or const call is guaranteed to have no side effects, we
+ cannot move it arbitrarily. Consider code like
+
+ char *s = something ();
+
+ while (1)
+ {
+ if (s)
+ t = strlen (s);
+ else
+ t = 0;
+ }
+
+ Here the strlen call cannot be moved out of the loop, even though
+ s is invariant. In addition to possibly creating a call with
+ invalid arguments, moving out a function call that is not executed
+ may cause performance regressions in case the call is costly and
+ not executed at all. */
+ return MOVE_PRESERVE_EXECUTION;
+ }
return MOVE_POSSIBLE;
}
/* Suppose that operand DEF is used inside the LOOP. Returns the outermost
- loop to that we could move the expresion using DEF if it did not have
+ loop to that we could move the expression using DEF if it did not have
other operands, i.e. the outermost loop enclosing LOOP in that the value
of DEF is invariant. */
static struct loop *
outermost_invariant_loop_expr (tree expr, struct loop *loop)
{
- char class = TREE_CODE_CLASS (TREE_CODE (expr));
+ enum tree_code_class class = TREE_CODE_CLASS (TREE_CODE (expr));
unsigned i, nops;
struct loop *max_loop = superloop_at_depth (loop, 1), *aloop;
|| is_gimple_min_invariant (expr))
return outermost_invariant_loop (expr, loop);
- if (class != '1'
- && class != '2'
- && class != 'e'
- && class != '<')
+ if (class != tcc_unary
+ && class != tcc_binary
+ && class != tcc_expression
+ && class != tcc_comparison)
return NULL;
- nops = first_rtl_op (TREE_CODE (expr));
+ nops = TREE_CODE_LENGTH (TREE_CODE (expr));
for (i = 0; i < nops; i++)
{
aloop = outermost_invariant_loop_expr (TREE_OPERAND (expr, i), loop);
static unsigned
stmt_cost (tree stmt)
{
- tree lhs, rhs;
+ tree rhs;
unsigned cost = 1;
/* Always try to create possibilities for unswitching. */
if (TREE_CODE (stmt) == COND_EXPR)
return LIM_EXPENSIVE;
- lhs = TREE_OPERAND (stmt, 0);
rhs = TREE_OPERAND (stmt, 1);
/* Hoisting memory references out should almost surely be a win. */
- if (!is_gimple_variable (lhs))
- cost += 20;
- if (is_gimple_addressable (rhs) && !is_gimple_variable (rhs))
+ if (stmt_references_memory_p (stmt))
cost += 20;
switch (TREE_CODE (rhs))
/* Unless the call is a builtin_constant_p; this always folds to a
constant, so moving it is useless. */
rhs = get_callee_fndecl (rhs);
- if (DECL_BUILT_IN (rhs)
+ if (DECL_BUILT_IN_CLASS (rhs) == BUILT_IN_NORMAL
&& DECL_FUNCTION_CODE (rhs) == BUILT_IN_CONSTANT_P)
return 0;
case FLOOR_MOD_EXPR:
case ROUND_MOD_EXPR:
case TRUNC_MOD_EXPR:
+ case RDIV_EXPR:
/* Division and multiplication are usually expensive. */
cost += 20;
break;
if (!add_dependency (val, lim_data, loop, true))
return false;
- FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, SSA_OP_VIRTUAL_USES)
+ FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, SSA_OP_VIRTUAL_USES | SSA_OP_VIRTUAL_KILLS)
if (!add_dependency (val, lim_data, loop, false))
return false;
if (flow_loop_nested_p (stmt_loop, level))
return;
- if (!LIM_DATA (stmt))
- abort ();
-
- if (level != LIM_DATA (stmt)->max_loop
- && !flow_loop_nested_p (LIM_DATA (stmt)->max_loop, level))
- abort ();
+ gcc_assert (LIM_DATA (stmt));
+ gcc_assert (level == LIM_DATA (stmt)->max_loop
+ || flow_loop_nested_p (LIM_DATA (stmt)->max_loop, level));
LIM_DATA (stmt)->tgt_loop = level;
for (dep = LIM_DATA (stmt)->depends; dep; dep = dep->next)
{
enum move_pos pos;
block_stmt_iterator bsi;
- tree stmt;
+ tree stmt, rhs;
bool maybe_never = ALWAYS_EXECUTED_IN (bb) == NULL;
struct loop *outermost = ALWAYS_EXECUTED_IN (bb);
continue;
}
- stmt_ann (stmt)->common.aux = xcalloc (1, sizeof (struct lim_aux_data));
+ /* If divisor is invariant, convert a/b to a*(1/b), allowing reciprocal
+ to be hoisted out of loop, saving expensive divide. */
+ if (pos == MOVE_POSSIBLE
+ && (rhs = TREE_OPERAND (stmt, 1)) != NULL
+ && TREE_CODE (rhs) == RDIV_EXPR
+ && flag_unsafe_math_optimizations
+ && outermost_invariant_loop_expr (TREE_OPERAND (rhs, 1),
+ loop_containing_stmt (stmt)) != NULL
+ && outermost_invariant_loop_expr (rhs,
+ loop_containing_stmt (stmt)) == NULL)
+ {
+ tree lhs, stmt1, stmt2, var, name;
+
+ lhs = TREE_OPERAND (stmt, 0);
+
+ /* stmt must be MODIFY_EXPR. */
+ var = create_tmp_var (TREE_TYPE (rhs), "reciptmp");
+ add_referenced_tmp_var (var);
+
+ stmt1 = build2 (MODIFY_EXPR, void_type_node, var,
+ build2 (RDIV_EXPR, TREE_TYPE (rhs),
+ build_real (TREE_TYPE (rhs), dconst1),
+ TREE_OPERAND (rhs, 1)));
+ name = make_ssa_name (var, stmt1);
+ TREE_OPERAND (stmt1, 0) = name;
+ stmt2 = build2 (MODIFY_EXPR, void_type_node, lhs,
+ build2 (MULT_EXPR, TREE_TYPE (rhs),
+ name, TREE_OPERAND (rhs, 0)));
+
+ /* Replace division stmt with reciprocal and multiply stmts.
+ The multiply stmt is not invariant, so update iterator
+ and avoid rescanning. */
+ bsi_replace (&bsi, stmt1, true);
+ bsi_insert_after (&bsi, stmt2, BSI_NEW_STMT);
+ SSA_NAME_DEF_STMT (lhs) = stmt2;
+
+ /* Continue processing with invariant reciprocal statment. */
+ stmt = stmt1;
+ }
+
+ stmt_ann (stmt)->aux = xcalloc (1, sizeof (struct lim_aux_data));
LIM_DATA (stmt)->always_executed_in = outermost;
if (maybe_never && pos == MOVE_PRESERVE_EXECUTION)
basic_block bb;
old_last_basic_block = last_basic_block;
- bsi_commit_edge_inserts (NULL);
+ bsi_commit_edge_inserts ();
for (i = old_last_basic_block; i < (unsigned) last_basic_block; i++)
{
bb = BASIC_BLOCK (i);
add_bb_to_loop (bb,
- find_common_loop (bb->succ->dest->loop_father,
- bb->pred->src->loop_father));
+ find_common_loop (single_pred (bb)->loop_father,
+ single_succ (bb)->loop_father));
}
}
/* Hoist the statements in basic block BB out of the loops prescribed by
- data stored in LIM_DATA structres associated with each statement. Callback
+ data stored in LIM_DATA structures associated with each statement. Callback
for walk_dominator_tree. */
static void
cost = LIM_DATA (stmt)->cost;
level = LIM_DATA (stmt)->tgt_loop;
free_lim_aux_data (LIM_DATA (stmt));
- stmt_ann (stmt)->common.aux = NULL;
+ stmt_ann (stmt)->aux = NULL;
if (!level)
{
}
/* Hoist the statements out of the loops prescribed by data stored in
- LIM_DATA structres associated with each statement.*/
+ LIM_DATA structures associated with each statement.*/
static void
move_computations (void)
fini_walk_dominator_tree (&walk_data);
loop_commit_inserts ();
- rewrite_into_ssa (false);
- if (bitmap_first_set_bit (vars_to_rename) >= 0)
- {
- /* The rewrite of ssa names may cause violation of loop closed ssa
- form invariants. TODO -- avoid these rewrites completely.
- Information in virtual phi nodes is sufficient for it. */
- rewrite_into_loop_closed_ssa ();
- }
- bitmap_clear (vars_to_rename);
+ if (need_ssa_update_p ())
+ rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
}
/* Checks whether the statement defining variable *INDEX can be hoisted
return true;
}
-/* Forces statements definining (invariant) SSA names in expression EXPR to be
+/* Forces statements defining (invariant) SSA names in expression EXPR to be
moved out of the LOOP. ORIG_LOOP is the loop in that EXPR is used. */
static void
force_move_till_expr (tree expr, struct loop *orig_loop, struct loop *loop)
{
- char class = TREE_CODE_CLASS (TREE_CODE (expr));
+ enum tree_code_class class = TREE_CODE_CLASS (TREE_CODE (expr));
unsigned i, nops;
if (TREE_CODE (expr) == SSA_NAME)
return;
}
- if (class != '1'
- && class != '2'
- && class != 'e'
- && class != '<')
+ if (class != tcc_unary
+ && class != tcc_binary
+ && class != tcc_expression
+ && class != tcc_comparison)
return;
- nops = first_rtl_op (TREE_CODE (expr));
+ nops = TREE_CODE_LENGTH (TREE_CODE (expr));
for (i = 0; i < nops; i++)
force_move_till_expr (TREE_OPERAND (expr, i), orig_loop, loop);
}
if (!def_bb
|| !flow_bb_inside_loop_p (loop, def_bb)
- || TEST_BIT (seen, stmt_ann (stmt)->uid))
+ || TEST_BIT (seen, get_stmt_uid (stmt)))
return;
- SET_BIT (seen, stmt_ann (stmt)->uid);
+ SET_BIT (seen, get_stmt_uid (stmt));
queue[(*in_queue)++] = stmt;
}
struct mem_ref **mem_refs,
bool *seen_call_stmt)
{
+ unsigned max_uid = max_stmt_uid + num_ssa_names;
tree *queue = xmalloc (sizeof (tree) * max_uid);
sbitmap seen = sbitmap_alloc (max_uid);
unsigned in_queue = 1;
- dataflow_t df;
- unsigned i, n;
+ unsigned i;
struct sra_data sra_data;
tree call;
tree val;
ssa_op_iter iter;
+ imm_use_iterator imm_iter;
+ use_operand_p use_p;
sbitmap_zero (seen);
sra_data.common_ref = NULL_TREE;
queue[0] = stmt;
- SET_BIT (seen, stmt_ann (stmt)->uid);
+ SET_BIT (seen, get_stmt_uid (stmt));
*seen_call_stmt = false;
while (in_queue)
case PHI_NODE:
for (i = 0; i < (unsigned) PHI_NUM_ARGS (stmt); i++)
- maybe_queue_var (PHI_ARG_DEF (stmt, i), loop,
- seen, queue, &in_queue);
+ if (TREE_CODE (PHI_ARG_DEF (stmt, i)) == SSA_NAME)
+ maybe_queue_var (PHI_ARG_DEF (stmt, i), loop,
+ seen, queue, &in_queue);
break;
default:
}
/* Find uses of virtual names. */
- df = get_immediate_uses (stmt);
- n = num_immediate_uses (df);
+ if (TREE_CODE (stmt) == PHI_NODE)
+ {
+ if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (stmt))))
+ FOR_EACH_IMM_USE_FAST (use_p, imm_iter, PHI_RESULT (stmt))
+ {
+ tree imm_stmt = USE_STMT (use_p);
- for (i = 0; i < n; i++)
- {
- stmt = immediate_use (df, i);
+ if (TEST_BIT (seen, get_stmt_uid (imm_stmt)))
+ continue;
- if (!flow_bb_inside_loop_p (loop, bb_for_stmt (stmt)))
- continue;
+ if (!flow_bb_inside_loop_p (loop, bb_for_stmt (imm_stmt)))
+ continue;
- if (TEST_BIT (seen, stmt_ann (stmt)->uid))
- continue;
- SET_BIT (seen, stmt_ann (stmt)->uid);
+ SET_BIT (seen, get_stmt_uid (imm_stmt));
- queue[in_queue++] = stmt;
+ queue[in_queue++] = imm_stmt;
+ }
}
+ else
+ FOR_EACH_SSA_TREE_OPERAND (val, stmt, iter, SSA_OP_VIRTUAL_DEFS)
+ FOR_EACH_IMM_USE_FAST (use_p, imm_iter, val)
+ {
+ tree imm_stmt = USE_STMT (use_p);
+
+ if (TEST_BIT (seen, get_stmt_uid (imm_stmt)))
+ continue;
+
+ if (!flow_bb_inside_loop_p (loop, bb_for_stmt (imm_stmt)))
+ continue;
+
+ SET_BIT (seen, get_stmt_uid (imm_stmt));
+
+ queue[in_queue++] = imm_stmt;
+ }
}
free (queue);
for (; mem_refs; mem_refs = mem_refs->next)
{
- FOR_EACH_SSA_TREE_OPERAND (var, mem_refs->stmt, iter,
- (SSA_OP_VIRTUAL_DEFS | SSA_OP_VUSE))
- {
- var = SSA_NAME_VAR (var);
- bitmap_set_bit (vars_to_rename, var_ann (var)->uid);
- }
+ FOR_EACH_SSA_TREE_OPERAND (var, mem_refs->stmt, iter, SSA_OP_ALL_VIRTUALS)
+ mark_sym_for_renaming (SSA_NAME_VAR (var));
*mem_refs->ref = tmp_var;
- modify_stmt (mem_refs->stmt);
+ update_stmt (mem_refs->stmt);
}
}
/* Records request for store motion of memory reference REF from LOOP.
- MEM_REFS is the list of occurences of the reference REF inside LOOP;
+ MEM_REFS is the list of occurrences of the reference REF inside LOOP;
these references are rewritten by a new temporary variable.
Exits from the LOOP are stored in EXITS, there are N_EXITS of them.
The initialization of the temporary variable is put to the preheader
/* Emit the load & stores. */
load = build (MODIFY_EXPR, void_type_node, tmp_var, ref);
- get_stmt_ann (load)->common.aux = xcalloc (1, sizeof (struct lim_aux_data));
+ get_stmt_ann (load)->aux = xcalloc (1, sizeof (struct lim_aux_data));
LIM_DATA (load)->max_loop = loop;
LIM_DATA (load)->tgt_loop = loop;
is_call_clobbered_ref (tree ref)
{
tree base;
+ HOST_WIDE_INT offset, size;
+ subvar_t sv;
+ subvar_t svars;
+ tree sref = ref;
+ if (TREE_CODE (sref) == COMPONENT_REF
+ && (sref = okay_component_ref_for_subvars (sref, &offset, &size)))
+ {
+ svars = get_subvars_for_var (sref);
+ for (sv = svars; sv; sv = sv->next)
+ {
+ if (overlap_subvar (offset, size, sv, NULL)
+ && is_call_clobbered (sv->var))
+ return true;
+ }
+ }
+
base = get_base_address (ref);
if (!base)
return true;
if (DECL_P (base))
- return is_call_clobbered (base);
+ {
+ if (var_can_have_subvars (base)
+ && (svars = get_subvars_for_var (base)))
+ {
+ for (sv = svars; sv; sv = sv->next)
+ if (is_call_clobbered (sv->var))
+ return true;
+ return false;
+ }
+ else
+ return is_call_clobbered (base);
+ }
- if (TREE_CODE (base) == INDIRECT_REF)
+ if (INDIRECT_REF_P (base))
{
/* Check whether the alias tags associated with the pointer
are call clobbered. */
return false;
}
- abort ();
+ gcc_unreachable ();
}
/* Determine whether all memory references inside LOOP corresponding to the
return;
}
- for (phi = phi_nodes (loop->header); phi; phi = TREE_CHAIN (phi))
+ for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi))
determine_lsm_reg (loop, exits, n_exits, PHI_RESULT (phi));
free (exits);
struct loop *loop;
basic_block bb;
+ if (!loops->tree_root->inner)
+ return;
+
/* Create a UID for each statement in the function. Ordering of the
UIDs is not important for this pass. */
- max_uid = 0;
+ max_stmt_uid = 0;
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
- tree phi;
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
- stmt_ann (bsi_stmt (bsi))->uid = max_uid++;
-
- for (phi = phi_nodes (bb); phi; phi = TREE_CHAIN (phi))
- stmt_ann (phi)->uid = max_uid++;
+ stmt_ann (bsi_stmt (bsi))->uid = max_stmt_uid++;
}
- compute_immediate_uses (TDFA_USE_VOPS, NULL);
-
/* Pass the loops from the outermost. For each virtual operand loop phi node
check whether all the references inside the loop correspond to a single
address, and if so, move them. */
loop = loop->outer;
if (loop == loops->tree_root)
{
- free_df ();
loop_commit_inserts ();
return;
}
for (i = 0; i < loop->num_nodes; i++)
{
+ edge_iterator ei;
bb = bbs[i];
if (dominated_by_p (CDI_DOMINATORS, loop->latch, bb))
if (TEST_BIT (contains_call, bb->index))
break;
- for (e = bb->succ; e; e = e->succ_next)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (!flow_bb_inside_loop_p (loop, e->dest))
break;
if (e)
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