-/* Rtl-level loop invariant motion.
+/* RTL-level loop invariant motion.
Copyright (C) 2004, 2005 Free Software Foundation, Inc.
-
+
This file is part of GCC.
-
+
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.
-
+
GCC is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
-
+
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA. */
/* This implements the loop invariant motion pass. It is very simple
- (no calls, libcalls, etc.). This should be sufficient to cleanup things like
- address arithmetics -- other more complicated invariants should be
+ (no calls, libcalls, etc.). This should be sufficient to cleanup things
+ like address arithmetics -- other more complicated invariants should be
eliminated on tree level either in tree-ssa-loop-im.c or in tree-ssa-pre.c.
-
+
We proceed loop by loop -- it is simpler than trying to handle things
globally and should not lose much. First we inspect all sets inside loop
and create a dependency graph on insns (saying "to move this insn, you must
We then need to determine what to move. We estimate the number of registers
used and move as many invariants as possible while we still have enough free
registers. We prefer the expensive invariants.
-
+
Then we move the selected invariants out of the loop, creating a new
temporaries for them if necessary. */
/* Whether to move the invariant. */
bool move;
- /* Cost if the invariant. */
+ /* Cost of the invariant. */
unsigned cost;
/* The invariants it depends on. */
static VEC(invariant_p,heap) *invariants;
+/* The dataflow object. */
+
+static struct df *df;
+
/* Test for possibility of invariantness of X. */
static bool
}
continue;
}
-
+
/* Use the data stored for the subloop to decide whether we may exit
through it. It is sufficient to do this for header of the loop,
as other basic blocks inside it must be dominated by it. */
|| REGNO_REG_CLASS (REGNO (x)) != NO_REGS));
}
-/* Finds definitions that may correspond to invariants in LOOP with body BODY.
- DF is the dataflow object. */
+/* Finds definitions that may correspond to invariants in LOOP with body
+ BODY. */
static void
-find_defs (struct loop *loop, basic_block *body, struct df *df)
+find_defs (struct loop *loop, basic_block *body)
{
unsigned i;
bitmap blocks = BITMAP_ALLOC (NULL);
}
/* Finds the invariants INSN depends on and store them to the DEPENDS_ON
- bitmap. DF is the dataflow object. */
+ bitmap. */
static bool
-check_dependencies (rtx insn, struct df *df, bitmap depends_on)
+check_dependencies (rtx insn, bitmap depends_on)
{
struct df_link *uses, *defs;
struct ref *use, *def;
/* Finds invariant in INSN. ALWAYS_REACHED is true if the insn is always
executed. ALWAYS_EXECUTED is true if the insn is always executed,
- unless the program ends due to a function call. DF is the dataflow
- object. */
+ unless the program ends due to a function call. */
static void
-find_invariant_insn (rtx insn, bool always_reached, bool always_executed,
- struct df *df)
+find_invariant_insn (rtx insn, bool always_reached, bool always_executed)
{
struct ref *ref;
struct def *def;
|| find_reg_note (insn, REG_LIBCALL, NULL_RTX)
|| find_reg_note (insn, REG_NO_CONFLICT, NULL_RTX))
return;
-
+
set = single_set (insn);
if (!set)
return;
}
depends_on = BITMAP_ALLOC (NULL);
- if (!check_dependencies (insn, df, depends_on))
+ if (!check_dependencies (insn, depends_on))
{
BITMAP_FREE (depends_on);
return;
create_new_invariant (def, insn, depends_on, always_executed);
}
-/* Record registers used in INSN that have a unique invariant definition.
- DF is the dataflow object. */
+/* Record registers used in INSN that have a unique invariant definition. */
static void
-record_uses (rtx insn, struct df *df)
+record_uses (rtx insn)
{
struct df_link *uses, *defs;
struct ref *use, *def;
/* Finds invariants in INSN. ALWAYS_REACHED is true if the insn is always
executed. ALWAYS_EXECUTED is true if the insn is always executed,
- unless the program ends due to a function call. DF is the dataflow
- object. */
+ unless the program ends due to a function call. */
static void
-find_invariants_insn (rtx insn, bool always_reached, bool always_executed,
- struct df *df)
+find_invariants_insn (rtx insn, bool always_reached, bool always_executed)
{
- find_invariant_insn (insn, always_reached, always_executed, df);
- record_uses (insn, df);
+ find_invariant_insn (insn, always_reached, always_executed);
+ record_uses (insn);
}
/* Finds invariants in basic block BB. ALWAYS_REACHED is true if the
basic block is always executed. ALWAYS_EXECUTED is true if the basic
block is always executed, unless the program ends due to a function
- call. DF is the dataflow object. */
+ call. */
static void
-find_invariants_bb (basic_block bb, bool always_reached, bool always_executed,
- struct df *df)
+find_invariants_bb (basic_block bb, bool always_reached, bool always_executed)
{
rtx insn;
if (!INSN_P (insn))
continue;
- find_invariants_insn (insn, always_reached, always_executed, df);
+ find_invariants_insn (insn, always_reached, always_executed);
if (always_reached
&& CALL_P (insn)
/* Finds invariants in LOOP with body BODY. ALWAYS_REACHED is the bitmap of
basic blocks in BODY that are always executed. ALWAYS_EXECUTED is the
bitmap of basic blocks in BODY that are always executed unless the program
- ends due to a function call. DF is the dataflow object. */
+ ends due to a function call. */
static void
find_invariants_body (struct loop *loop, basic_block *body,
- bitmap always_reached, bitmap always_executed,
- struct df *df)
+ bitmap always_reached, bitmap always_executed)
{
unsigned i;
for (i = 0; i < loop->num_nodes; i++)
find_invariants_bb (body[i],
bitmap_bit_p (always_reached, i),
- bitmap_bit_p (always_executed, i),
- df);
+ bitmap_bit_p (always_executed, i));
}
-/* Finds invariants in LOOP. DF is the dataflow object. */
+/* Finds invariants in LOOP. */
static void
-find_invariants (struct loop *loop, struct df *df)
+find_invariants (struct loop *loop)
{
bitmap may_exit = BITMAP_ALLOC (NULL);
bitmap always_reached = BITMAP_ALLOC (NULL);
compute_always_reached (loop, body, may_exit, always_reached);
compute_always_reached (loop, body, has_exit, always_executed);
- find_defs (loop, body, df);
- find_invariants_body (loop, body, always_reached, always_executed, df);
+ find_defs (loop, body);
+ find_invariants_body (loop, body, always_reached, always_executed);
BITMAP_FREE (always_reached);
BITMAP_FREE (always_executed);
}
}
-/* Determines which invariants to move. DF is the dataflow object. */
+/* Determines which invariants to move. */
static void
-find_invariants_to_move (struct df *df)
+find_invariants_to_move (void)
{
unsigned i, regs_used, n_inv_uses, regs_needed = 0, new_regs;
struct invariant *inv = NULL;
}
}
-/* Move invariant INVNO out of the LOOP. DF is the dataflow object. */
+/* Move invariant INVNO out of the LOOP. */
static void
-move_invariant_reg (struct loop *loop, unsigned invno, struct df *df)
+move_invariant_reg (struct loop *loop, unsigned invno)
{
struct invariant *inv = VEC_index (invariant_p, invariants, invno);
unsigned i;
{
EXECUTE_IF_SET_IN_BITMAP (inv->depends_on, 0, i, bi)
{
- move_invariant_reg (loop, i, df);
+ move_invariant_reg (loop, i);
}
}
}
/* Move selected invariant out of the LOOP. Newly created regs are marked
- in TEMPORARY_REGS. DF is the dataflow object. */
+ in TEMPORARY_REGS. */
static void
-move_invariants (struct loop *loop, struct df *df)
+move_invariants (struct loop *loop)
{
struct invariant *inv;
unsigned i;
for (i = 0; VEC_iterate (invariant_p, invariants, i, inv); i++)
{
if (inv->move)
- move_invariant_reg (loop, i, df);
+ move_invariant_reg (loop, i);
}
}
invariants = VEC_alloc (invariant_p, heap, 100);
}
-/* Frees the data allocated by invariant motion. DF is the dataflow
- object. */
+/* Frees the data allocated by invariant motion. */
static void
-free_inv_motion_data (struct df *df)
+free_inv_motion_data (void)
{
unsigned i;
struct def *def;
VEC_free (invariant_p, heap, invariants);
}
-/* Move the invariants out of the LOOP. DF is the dataflow object. */
+/* Move the invariants out of the LOOP. */
static void
-move_single_loop_invariants (struct loop *loop, struct df *df)
+move_single_loop_invariants (struct loop *loop)
{
init_inv_motion_data ();
- find_invariants (loop, df);
- find_invariants_to_move (df);
- move_invariants (loop, df);
+ find_invariants (loop);
+ find_invariants_to_move ();
+ move_invariants (loop);
- free_inv_motion_data (df);
+ free_inv_motion_data ();
}
/* Releases the auxiliary data for LOOP. */
{
struct loop *loop;
unsigned i;
- struct df *df = df_init ();
+
+ df = df_init ();
/* Process the loops, innermost first. */
loop = loops->tree_root;
while (loop != loops->tree_root)
{
- move_single_loop_invariants (loop, df);
+ move_single_loop_invariants (loop);
if (loop->next)
{
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