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
+Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#undef BASELINE
#include "expr.h"
#include "recog.h"
#include "dse.h"
+#include "optabs.h"
#include "dbgcnt.h"
/* This file contains three techniques for performing Dead Store
rtx mem_addr;
/* If this is non-zero, it is the alias set of a spill location. */
- HOST_WIDE_INT alias_set;
+ alias_set_type alias_set;
/* The offset of the first and byte before the last byte associated
with the operation. */
int group_id;
/* If this is non-zero, it is the alias set of a spill location. */
- HOST_WIDE_INT alias_set;
+ alias_set_type alias_set;
/* The offset of the first and byte after the last byte associated
with the operation. If begin == end == 0, the read did not have
int offset_map_size_n, offset_map_size_p;
};
typedef struct group_info *group_info_t;
+typedef const struct group_info *const_group_info_t;
static alloc_pool rtx_group_info_pool;
/* Tables of group_info structures, hashed by base value. */
/* Hash table element to look up the mode for an alias set. */
struct clear_alias_mode_holder
{
- HOST_WIDE_INT alias_set;
+ alias_set_type alias_set;
enum machine_mode mode;
};
/* Find the entry associated with ALIAS_SET. */
static struct clear_alias_mode_holder *
-clear_alias_set_lookup (HOST_WIDE_INT alias_set)
+clear_alias_set_lookup (alias_set_type alias_set)
{
struct clear_alias_mode_holder tmp_holder;
void **slot;
static int
invariant_group_base_eq (const void *p1, const void *p2)
{
- const group_info_t gi1 = (const group_info_t) p1;
- const group_info_t gi2 = (const group_info_t) p2;
+ const_group_info_t gi1 = (const_group_info_t) p1;
+ const_group_info_t gi2 = (const_group_info_t) p2;
return rtx_equal_p (gi1->rtx_base, gi2->rtx_base);
}
static hashval_t
invariant_group_base_hash (const void *p)
{
- const group_info_t gi = (const group_info_t) p;
+ const_group_info_t gi = (const_group_info_t) p;
int do_not_record;
return hash_rtx (gi->rtx_base, Pmode, &do_not_record, NULL, false);
}
INSN_UID (insn_info->insn));
if (insn_info->store_rec->alias_set)
fprintf (dump_file, "alias set %d\n",
- (int)insn_info->store_rec->alias_set);
+ (int) insn_info->store_rec->alias_set);
else
fprintf (dump_file, "\n");
}
while (*ptr)
{
read_info_t next = (*ptr)->next;
- if ( (*ptr)->alias_set == 0 )
+ if ((*ptr)->alias_set == 0)
{
pool_free (read_info_pool, *ptr);
*ptr = next;
static bool
canon_address (rtx mem,
- HOST_WIDE_INT *alias_set_out,
+ alias_set_type *alias_set_out,
int *group_id,
HOST_WIDE_INT *offset,
cselib_val **base)
if (clear_alias_sets)
{
/* If this is a spill, do not do any further processing. */
- HOST_WIDE_INT alias_set = MEM_ALIAS_SET (mem);
+ alias_set_type alias_set = MEM_ALIAS_SET (mem);
if (dump_file)
- fprintf (dump_file, "found alias set %d\n", (int)alias_set);
+ fprintf (dump_file, "found alias set %d\n", (int) alias_set);
if (bitmap_bit_p (clear_alias_sets, alias_set))
{
struct clear_alias_mode_holder *entry
if (dump_file)
fprintf (dump_file,
"disqualifying alias set %d, (%s) != (%s)\n",
- (int)alias_set, GET_MODE_NAME (entry->mode),
+ (int) alias_set, GET_MODE_NAME (entry->mode),
GET_MODE_NAME (GET_MODE (mem)));
bitmap_set_bit (disqualified_clear_alias_sets, alias_set);
rtx mem;
HOST_WIDE_INT offset = 0;
HOST_WIDE_INT width = 0;
- HOST_WIDE_INT spill_alias_set;
+ alias_set_type spill_alias_set;
insn_info_t insn_info = bb_info->last_insn;
store_info_t store_info = NULL;
int group_id;
if (dump_file)
fprintf (dump_file, " processing spill store %d(%s)\n",
- (int)spill_alias_set, GET_MODE_NAME (GET_MODE (mem)));
+ (int) spill_alias_set, GET_MODE_NAME (GET_MODE (mem)));
}
else if (group_id >= 0)
{
}
if (dump_file)
fprintf (dump_file, " trying spill store in insn=%d alias_set=%d\n",
- INSN_UID (ptr->insn), (int)s_info->alias_set);
+ INSN_UID (ptr->insn), (int) s_info->alias_set);
}
else if ((s_info->group_id == group_id)
&& (s_info->cse_base == base))
}
+/* If the modes are different and the value's source and target do not
+ line up, we need to extract the value from lower part of the rhs of
+ the store, shift it, and then put it into a form that can be shoved
+ into the read_insn. This function generates a right SHIFT of a
+ value that is at least ACCESS_SIZE bytes wide of READ_MODE. The
+ shift sequence is returned or NULL if we failed to find a
+ shift. */
+
+static rtx
+find_shift_sequence (rtx read_reg,
+ int access_size,
+ store_info_t store_info,
+ read_info_t read_info,
+ int shift)
+{
+ enum machine_mode store_mode = GET_MODE (store_info->mem);
+ enum machine_mode read_mode = GET_MODE (read_info->mem);
+
+ /* Some machines like the x86 have shift insns for each size of
+ operand. Other machines like the ppc or the ia-64 may only have
+ shift insns that shift values within 32 or 64 bit registers.
+ This loop tries to find the smallest shift insn that will right
+ justify the value we want to read but is available in one insn on
+ the machine. */
+
+ for (; access_size < UNITS_PER_WORD; access_size *= 2)
+ {
+ rtx target, new_reg;
+ enum machine_mode new_mode;
+
+ /* Try a wider mode if truncating the store mode to ACCESS_SIZE
+ bytes requires a real instruction. */
+ if (access_size < GET_MODE_SIZE (store_mode)
+ && !TRULY_NOOP_TRUNCATION (access_size * BITS_PER_UNIT,
+ GET_MODE_BITSIZE (store_mode)))
+ continue;
+
+ new_mode = smallest_mode_for_size (access_size * BITS_PER_UNIT,
+ GET_MODE_CLASS (read_mode));
+ new_reg = gen_reg_rtx (new_mode);
+
+ start_sequence ();
+
+ /* In theory we could also check for an ashr. Ian Taylor knows
+ of one dsp where the cost of these two was not the same. But
+ this really is a rare case anyway. */
+ target = expand_binop (new_mode, lshr_optab, new_reg,
+ GEN_INT (shift), new_reg, 1, OPTAB_DIRECT);
+
+ if (target == new_reg)
+ {
+ rtx shift_seq = get_insns ();
+ end_sequence ();
+
+ /* If cost is too great, set target to NULL and
+ let the iteration happen. */
+ if (shift_seq != NULL)
+ {
+ int cost = 0;
+ rtx insn;
+
+ for (insn = shift_seq; insn != NULL_RTX; insn = NEXT_INSN (insn))
+ if (INSN_P (insn))
+ cost += insn_rtx_cost (PATTERN (insn));
+
+ /* The computation up to here is essentially independent
+ of the arguments and could be precomputed. It may
+ not be worth doing so. We could precompute if
+ worthwhile or at least cache the results. The result
+ technically depends on SHIFT, ACCESS_SIZE, and
+ GET_MODE_CLASS (READ_MODE). But in practice the
+ answer will depend only on ACCESS_SIZE. */
+
+ if (cost <= COSTS_N_INSNS (1))
+ {
+ /* We found an acceptable shift. Generate a move to
+ take the value from the store and put it into the
+ shift pseudo, then shift it, then generate another
+ move to put in into the target of the read. */
+ start_sequence ();
+ emit_move_insn (new_reg, gen_lowpart (new_mode, store_info->rhs));
+ emit_insn (shift_seq);
+ convert_move (read_reg, new_reg, 1);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, " -- adding extract insn r%d:%s = r%d:%s\n",
+ REGNO (new_reg), GET_MODE_NAME (new_mode),
+ REGNO (store_info->rhs), GET_MODE_NAME (store_mode));
+
+ fprintf (dump_file, " -- with shift of r%d by %d\n",
+ REGNO(new_reg), shift);
+ fprintf (dump_file, " -- and second extract insn r%d:%s = r%d:%s\n",
+ REGNO (read_reg), GET_MODE_NAME (read_mode),
+ REGNO (new_reg), GET_MODE_NAME (new_mode));
+ }
+
+ /* Get the three insn sequence and return it. */
+ shift_seq = get_insns ();
+ end_sequence ();
+ return shift_seq;
+ }
+ }
+ }
+ else
+ /* End the sequence. */
+ end_sequence ();
+ }
+
+ return NULL;
+}
+
+
/* Take a sequence of:
A <- r1
...
...
... <- r2
- The STORE_INFO and STORE_INFO are for the store and the READ_INFO
+ or
+
+ r3 <- extract (r1)
+ r3 <- r3 >> shift
+ r2 <- extract (r3)
+ ... <- r2
+
+ or
+
+ r2 <- extract (r1)
+ ... <- r2
+
+ Depending on the alignment and the mode of the store and
+ subsequent load.
+
+
+ The STORE_INFO and STORE_INSN are for the store and READ_INFO
and READ_INSN are for the read. Return true if the replacement
went ok. */
replace_read (store_info_t store_info, insn_info_t store_insn,
read_info_t read_info, insn_info_t read_insn, rtx *loc)
{
+ enum machine_mode store_mode = GET_MODE (store_info->mem);
+ enum machine_mode read_mode = GET_MODE (read_info->mem);
+ int shift;
+ int access_size; /* In bytes. */
+ rtx read_reg = gen_reg_rtx (read_mode);
+ rtx shift_seq = NULL;
+
if (!dbg_cnt (dse))
return false;
+ if (GET_MODE_CLASS (read_mode) != GET_MODE_CLASS (store_mode))
+ return false;
+
+ /* To get here the read is within the boundaries of the write so
+ shift will never be negative. Start out with the shift being in
+ bytes. */
+ if (BYTES_BIG_ENDIAN)
+ shift = store_info->end - read_info->end;
+ else
+ shift = read_info->begin - store_info->begin;
+
+ access_size = shift + GET_MODE_SIZE (read_mode);
+
+ /* From now on it is bits. */
+ shift *= BITS_PER_UNIT;
+
+ /* We need to keep this in perspective. We are replacing a read
+ with a sequence of insns, but the read will almost certainly be
+ in cache, so it is not going to be an expensive one. Thus, we
+ are not willing to do a multi insn shift or worse a subroutine
+ call to get rid of the read. */
+ if (shift)
+ {
+ if (access_size > UNITS_PER_WORD || FLOAT_MODE_P (store_mode))
+ return false;
+
+ shift_seq = find_shift_sequence (read_reg, access_size, store_info,
+ read_info, shift);
+ if (!shift_seq)
+ return false;
+ }
+
if (dump_file)
- fprintf (dump_file, "generating move to replace load at %d from store at %d\n",
+ fprintf (dump_file, "replacing load at %d from store at %d\n",
INSN_UID (read_insn->insn), INSN_UID (store_insn->insn));
- if (GET_MODE (store_info->mem) == GET_MODE (read_info->mem))
+
+ if (validate_change (read_insn->insn, loc, read_reg, 0))
{
- rtx new_reg = gen_reg_rtx (GET_MODE (store_info->mem));
- if (validate_change (read_insn->insn, loc, new_reg, 0))
+ rtx insns;
+ deferred_change_t deferred_change = pool_alloc (deferred_change_pool);
+
+ if (read_mode == store_mode)
{
- rtx insns;
- deferred_change_t deferred_change = pool_alloc (deferred_change_pool);
-
start_sequence ();
- emit_move_insn (new_reg, store_info->rhs);
+
+ /* The modes are the same and everything lines up. Just
+ generate a simple move. */
+ emit_move_insn (read_reg, store_info->rhs);
+ if (dump_file)
+ fprintf (dump_file, " -- adding move insn r%d = r%d\n",
+ REGNO (read_reg), REGNO (store_info->rhs));
insns = get_insns ();
end_sequence ();
- emit_insn_before (insns, store_insn->insn);
-
- if (dump_file)
- fprintf (dump_file, " -- adding move insn %d: r%d = r%d\n",
- INSN_UID (insns), REGNO (new_reg), REGNO (store_info->rhs));
-
- /* And now for the cludge part: cselib croaks if you just
- return at this point. There are two reasons for this:
-
- 1) Cselib has an idea of how many pseudos there are and
- that does not include the new one we just added.
-
- 2) Cselib does not know about the move insn we added
- above the store_info, and there is no way to tell it
- about it, because it has "moved on".
-
- So we are just going to have to lie. The move insn is
- not really an issue, cselib did not see it. But the use
- of the new pseudo read_insn is a real problem. The way
- that we solve this problem is that we are just going to
- put the mem back keep a table of mems to get rid of. At
- the end of the basic block we can put it back. */
-
- *loc = read_info->mem;
- deferred_change->next = deferred_change_list;
- deferred_change_list = deferred_change;
- deferred_change->loc = loc;
- deferred_change->reg = new_reg;
-
- /* Get rid of the read_info, from the point of view of the
- rest of dse, play like this read never happened. */
- read_insn->read_rec = read_info->next;
- pool_free (read_info_pool, read_info);
- return true;
}
- else
+ else if (shift)
+ insns = shift_seq;
+ else
{
+ /* The modes are different but the lsb are in the same
+ place, we need to extract the value in the right from the
+ rhs of the store. */
+ start_sequence ();
+ convert_move (read_reg, store_info->rhs, 1);
+
if (dump_file)
- fprintf (dump_file, " -- validation failure\n");
- return false;
+ fprintf (dump_file, " -- adding extract insn r%d:%s = r%d:%s\n",
+ REGNO (read_reg), GET_MODE_NAME (read_mode),
+ REGNO (store_info->rhs), GET_MODE_NAME (store_mode));
+ insns = get_insns ();
+ end_sequence ();
}
+
+ /* Insert this right before the store insn where it will be safe
+ from later insns that might change it before the read. */
+ emit_insn_before (insns, store_insn->insn);
+
+ /* And now for the kludge part: cselib croaks if you just
+ return at this point. There are two reasons for this:
+
+ 1) Cselib has an idea of how many pseudos there are and
+ that does not include the new ones we just added.
+
+ 2) Cselib does not know about the move insn we added
+ above the store_info, and there is no way to tell it
+ about it, because it has "moved on".
+
+ Problem (1) is fixable with a certain amount of engineering.
+ Problem (2) is requires starting the bb from scratch. This
+ could be expensive.
+
+ So we are just going to have to lie. The move/extraction
+ insns are not really an issue, cselib did not see them. But
+ the use of the new pseudo read_insn is a real problem because
+ cselib has not scanned this insn. The way that we solve this
+ problem is that we are just going to put the mem back for now
+ and when we are finished with the block, we undo this. We
+ keep a table of mems to get rid of. At the end of the basic
+ block we can put them back. */
+
+ *loc = read_info->mem;
+ deferred_change->next = deferred_change_list;
+ deferred_change_list = deferred_change;
+ deferred_change->loc = loc;
+ deferred_change->reg = read_reg;
+
+ /* Get rid of the read_info, from the point of view of the
+ rest of dse, play like this read never happened. */
+ read_insn->read_rec = read_info->next;
+ pool_free (read_info_pool, read_info);
+ return true;
}
- else
+ else
{
- /* Someone with excellent rtl skills needs to fill this in. You
- are guaranteed that the read is of the same size or smaller
- than the store, and that the read does not hang off one of
- the ends of the store. But the offsets of each must be
- checked because the read does not have to line up on either
- end of the store so the begin fields need to be examined in
- both the store_info and read_info. */
if (dump_file)
- fprintf (dump_file, " -- complex load, currently unsupported.\n");
+ fprintf (dump_file, " -- validation failure\n");
return false;
}
}
-
/* A for_each_rtx callback in which DATA is the bb_info. Check to see
if LOC is a mem and if it is look at the address and kill any
appropriate stores that may be active. */
insn_info_t insn_info;
HOST_WIDE_INT offset = 0;
HOST_WIDE_INT width = 0;
- HOST_WIDE_INT spill_alias_set = 0;
+ alias_set_type spill_alias_set = 0;
cselib_val *base = NULL;
int group_id;
read_info_t read_info;
if (dump_file)
fprintf (dump_file, " processing spill load %d\n",
- (int)spill_alias_set);
+ (int) spill_alias_set);
while (i_ptr)
{
void
-dse_record_singleton_alias_set (HOST_WIDE_INT alias_set,
+dse_record_singleton_alias_set (alias_set_type alias_set,
enum machine_mode mode)
{
struct clear_alias_mode_holder tmp_holder;
/* Remove ALIAS_SET from the sets of stack slots being considered. */
void
-dse_invalidate_singleton_alias_set (HOST_WIDE_INT alias_set)
+dse_invalidate_singleton_alias_set (alias_set_type alias_set)
{
if ((!gate_dse()) || !alias_set)
return;
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func |
- TODO_df_finish |
+ TODO_df_finish | TODO_verify_rtl_sharing |
TODO_ggc_collect, /* todo_flags_finish */
'w' /* letter */
};
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func |
- TODO_df_finish |
+ TODO_df_finish | TODO_verify_rtl_sharing |
TODO_ggc_collect, /* todo_flags_finish */
'w' /* letter */
};
-
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