5) Delete the insns that the global analysis has indicated are
unnecessary.
- 6) Cleanup.
+ 6) Delete insns that store the same value as preceeding store
+ where the earlier store couldn't be eliminated.
+
+ 7) Cleanup.
This step uses cselib and canon_rtx to build the largest expression
possible for each address. This pass is a forwards pass through
/* False means this is a clobber. */
bool is_set;
+ /* False if a single HOST_WIDE_INT bitmap is used for positions_needed. */
+ bool is_large;
+
/* The id of the mem group of the base address. If rtx_varies_p is
true, this is -1. Otherwise, it is the index into the group
table. */
/* The offset of the first and byte before the last byte associated
with the operation. */
- int begin, end;
+ HOST_WIDE_INT begin, end;
+
+ union
+ {
+ /* A bitmask as wide as the number of bytes in the word that
+ contains a 1 if the byte may be needed. The store is unused if
+ all of the bits are 0. This is used if IS_LARGE is false. */
+ unsigned HOST_WIDE_INT small_bitmask;
+
+ struct
+ {
+ /* A bitmap with one bit per byte. Cleared bit means the position
+ is needed. Used if IS_LARGE is false. */
+ bitmap bitmap;
- /* An bitmask as wide as the number of bytes in the word that
- contains a 1 if the byte may be needed. The store is unused if
- all of the bits are 0. */
- unsigned HOST_WIDE_INT positions_needed;
+ /* Number of set bits (i.e. unneeded bytes) in BITMAP. If it is
+ equal to END - BEGIN, the whole store is unused. */
+ int count;
+ } large;
+ } positions_needed;
/* The next store info for this insn. */
struct store_info *next;
/* The right hand side of the store. This is used if there is a
subsequent reload of the mems address somewhere later in the
basic block. */
- rtx rhs;
+ rtx rhs;
+
+ /* If rhs is or holds a constant, this contains that constant,
+ otherwise NULL. */
+ rtx const_rhs;
+
+ /* Set if this store stores the same constant value as REDUNDANT_REASON
+ insn stored. These aren't eliminated early, because doing that
+ might prevent the earlier larger store to be eliminated. */
+ struct insn_info *redundant_reason;
};
/* Return a bitmask with the first N low bits set. */
while (store_info)
{
store_info_t next = store_info->next;
+ if (store_info->is_large)
+ BITMAP_FREE (store_info->positions_needed.large.bitmap);
if (store_info->cse_base)
pool_free (cse_store_info_pool, store_info);
else
{
HOST_WIDE_INT i;
- if ((offset > -MAX_OFFSET) && (offset < MAX_OFFSET))
+ if (offset > -MAX_OFFSET && offset + width < MAX_OFFSET)
for (i=offset; i<offset+width; i++)
{
bitmap store1;
store_info = store_info->next;
store_info->rhs = NULL;
+ store_info->const_rhs = NULL;
ptr = ptr->next_local_store;
}
}
+/* Mark byte POS bytes from the beginning of store S_INFO as unneeded. */
+
+static inline void
+set_position_unneeded (store_info_t s_info, int pos)
+{
+ if (__builtin_expect (s_info->is_large, false))
+ {
+ if (!bitmap_bit_p (s_info->positions_needed.large.bitmap, pos))
+ {
+ s_info->positions_needed.large.count++;
+ bitmap_set_bit (s_info->positions_needed.large.bitmap, pos);
+ }
+ }
+ else
+ s_info->positions_needed.small_bitmask
+ &= ~(((unsigned HOST_WIDE_INT) 1) << pos);
+}
+
+/* Mark the whole store S_INFO as unneeded. */
+
+static inline void
+set_all_positions_unneeded (store_info_t s_info)
+{
+ if (__builtin_expect (s_info->is_large, false))
+ {
+ int pos, end = s_info->end - s_info->begin;
+ for (pos = 0; pos < end; pos++)
+ bitmap_set_bit (s_info->positions_needed.large.bitmap, pos);
+ s_info->positions_needed.large.count = end;
+ }
+ else
+ s_info->positions_needed.small_bitmask = (unsigned HOST_WIDE_INT) 0;
+}
+
+/* Return TRUE if any bytes from S_INFO store are needed. */
+
+static inline bool
+any_positions_needed_p (store_info_t s_info)
+{
+ if (__builtin_expect (s_info->is_large, false))
+ return (s_info->positions_needed.large.count
+ < s_info->end - s_info->begin);
+ else
+ return (s_info->positions_needed.small_bitmask
+ != (unsigned HOST_WIDE_INT) 0);
+}
+
+/* Return TRUE if all bytes START through START+WIDTH-1 from S_INFO
+ store are needed. */
+
+static inline bool
+all_positions_needed_p (store_info_t s_info, int start, int width)
+{
+ if (__builtin_expect (s_info->is_large, false))
+ {
+ int end = start + width;
+ while (start < end)
+ if (bitmap_bit_p (s_info->positions_needed.large.bitmap, start++))
+ return false;
+ return true;
+ }
+ else
+ {
+ unsigned HOST_WIDE_INT mask = lowpart_bitmask (width) << start;
+ return (s_info->positions_needed.small_bitmask & mask) == mask;
+ }
+}
+
+
+static rtx get_stored_val (store_info_t, enum machine_mode, HOST_WIDE_INT,
+ HOST_WIDE_INT, basic_block, bool);
+
+
/* BODY is an instruction pattern that belongs to INSN. Return 1 if
there is a candidate store, after adding it to the appropriate
local store group if so. */
static int
record_store (rtx body, bb_info_t bb_info)
{
- rtx mem;
+ rtx mem, rhs, const_rhs;
HOST_WIDE_INT offset = 0;
HOST_WIDE_INT width = 0;
alias_set_type spill_alias_set;
store_info_t store_info = NULL;
int group_id;
cselib_val *base = NULL;
- insn_info_t ptr, last;
+ insn_info_t ptr, last, redundant_reason;
bool store_is_unused;
if (GET_CODE (body) != SET && GET_CODE (body) != CLOBBER)
return 0;
+ mem = SET_DEST (body);
+
/* If this is not used, then this cannot be used to keep the insn
from being deleted. On the other hand, it does provide something
that can be used to prove that another store is dead. */
store_is_unused
- = (find_reg_note (insn_info->insn, REG_UNUSED, body) != NULL);
+ = (find_reg_note (insn_info->insn, REG_UNUSED, mem) != NULL);
/* Check whether that value is a suitable memory location. */
- mem = SET_DEST (body);
if (!MEM_P (mem))
{
/* If the set or clobber is unused, then it does not effect our
fprintf (dump_file, " adding wild read for (clobber (mem:BLK (scratch))\n");
add_wild_read (bb_info);
insn_info->cannot_delete = true;
+ return 0;
}
- else if (!store_is_unused)
+ /* Handle (set (mem:BLK (addr) [... S36 ...]) (const_int 0))
+ as memset (addr, 0, 36); */
+ else if (!MEM_SIZE (mem)
+ || !CONST_INT_P (MEM_SIZE (mem))
+ || GET_CODE (body) != SET
+ || INTVAL (MEM_SIZE (mem)) <= 0
+ || INTVAL (MEM_SIZE (mem)) > MAX_OFFSET
+ || !CONST_INT_P (SET_SRC (body)))
{
- /* If the set or clobber is unused, then it does not effect our
- ability to get rid of the entire insn. */
- insn_info->cannot_delete = true;
- clear_rhs_from_active_local_stores ();
+ if (!store_is_unused)
+ {
+ /* If the set or clobber is unused, then it does not effect our
+ ability to get rid of the entire insn. */
+ insn_info->cannot_delete = true;
+ clear_rhs_from_active_local_stores ();
+ }
+ return 0;
}
- return 0;
}
/* We can still process a volatile mem, we just cannot delete it. */
if (MEM_VOLATILE_P (mem))
- insn_info->cannot_delete = true;
+ insn_info->cannot_delete = true;
if (!canon_address (mem, &spill_alias_set, &group_id, &offset, &base))
{
return 0;
}
- width = GET_MODE_SIZE (GET_MODE (mem));
+ if (GET_MODE (mem) == BLKmode)
+ width = INTVAL (MEM_SIZE (mem));
+ else
+ {
+ width = GET_MODE_SIZE (GET_MODE (mem));
+ gcc_assert ((unsigned) width <= HOST_BITS_PER_WIDE_INT);
+ }
if (spill_alias_set)
{
bitmap store1 = clear_alias_group->store1_p;
bitmap store2 = clear_alias_group->store2_p;
+
+ gcc_assert (GET_MODE (mem) != BLKmode);
if (bitmap_bit_p (store1, spill_alias_set))
bitmap_set_bit (store2, spill_alias_set);
(int)offset, (int)(offset+width));
}
+ const_rhs = rhs = NULL_RTX;
+ if (GET_CODE (body) == SET
+ /* No place to keep the value after ra. */
+ && !reload_completed
+ && (REG_P (SET_SRC (body))
+ || GET_CODE (SET_SRC (body)) == SUBREG
+ || CONSTANT_P (SET_SRC (body)))
+ && !MEM_VOLATILE_P (mem)
+ /* Sometimes the store and reload is used for truncation and
+ rounding. */
+ && !(FLOAT_MODE_P (GET_MODE (mem)) && (flag_float_store)))
+ {
+ rhs = SET_SRC (body);
+ if (CONSTANT_P (rhs))
+ const_rhs = rhs;
+ else if (body == PATTERN (insn_info->insn))
+ {
+ rtx tem = find_reg_note (insn_info->insn, REG_EQUAL, NULL_RTX);
+ if (tem && CONSTANT_P (XEXP (tem, 0)))
+ const_rhs = XEXP (tem, 0);
+ }
+ if (const_rhs == NULL_RTX && REG_P (rhs))
+ {
+ rtx tem = cselib_expand_value_rtx (rhs, scratch, 5);
+
+ if (tem && CONSTANT_P (tem))
+ const_rhs = tem;
+ }
+ }
+
/* Check to see if this stores causes some other stores to be
dead. */
ptr = active_local_stores;
last = NULL;
+ redundant_reason = NULL;
while (ptr)
{
&& (GET_MODE (mem) == entry->mode))
{
del = true;
- s_info->positions_needed = (unsigned HOST_WIDE_INT) 0;
+ set_all_positions_unneeded (s_info);
}
if (dump_file)
fprintf (dump_file, " trying spill store in insn=%d alias_set=%d\n",
fprintf (dump_file, " trying store in insn=%d gid=%d[%d..%d)\n",
INSN_UID (ptr->insn), s_info->group_id,
(int)s_info->begin, (int)s_info->end);
- for (i = offset; i < offset+width; i++)
- if (i >= s_info->begin && i < s_info->end)
- s_info->positions_needed
- &= ~(((unsigned HOST_WIDE_INT) 1) << (i - s_info->begin));
+
+ /* Even if PTR won't be eliminated as unneeded, if both
+ PTR and this insn store the same constant value, we might
+ eliminate this insn instead. */
+ if (s_info->const_rhs
+ && const_rhs
+ && offset >= s_info->begin
+ && offset + width <= s_info->end
+ && all_positions_needed_p (s_info, offset - s_info->begin,
+ width))
+ {
+ if (GET_MODE (mem) == BLKmode)
+ {
+ if (GET_MODE (s_info->mem) == BLKmode
+ && s_info->const_rhs == const_rhs)
+ redundant_reason = ptr;
+ }
+ else if (s_info->const_rhs == const0_rtx
+ && const_rhs == const0_rtx)
+ redundant_reason = ptr;
+ else
+ {
+ rtx val;
+ start_sequence ();
+ val = get_stored_val (s_info, GET_MODE (mem),
+ offset, offset + width,
+ BLOCK_FOR_INSN (insn_info->insn),
+ true);
+ if (get_insns () != NULL)
+ val = NULL_RTX;
+ end_sequence ();
+ if (val && rtx_equal_p (val, const_rhs))
+ redundant_reason = ptr;
+ }
+ }
+
+ for (i = MAX (offset, s_info->begin);
+ i < offset + width && i < s_info->end;
+ i++)
+ set_position_unneeded (s_info, i - s_info->begin);
}
else if (s_info->rhs)
/* Need to see if it is possible for this store to overwrite
GET_MODE (s_info->mem),
s_info->mem_addr,
mem, rtx_varies_p))
- s_info->rhs = NULL;
+ {
+ s_info->rhs = NULL;
+ s_info->const_rhs = NULL;
+ }
}
/* An insn can be deleted if every position of every one of
its s_infos is zero. */
- if (s_info->positions_needed != (unsigned HOST_WIDE_INT) 0)
+ if (any_positions_needed_p (s_info)
+ || ptr->cannot_delete)
del = false;
-
+
if (del)
{
insn_info_t insn_to_delete = ptr;
ptr = next;
}
- gcc_assert ((unsigned) width <= HOST_BITS_PER_WIDE_INT);
-
/* Finish filling in the store_info. */
store_info->next = insn_info->store_rec;
insn_info->store_rec = store_info;
store_info->alias_set = spill_alias_set;
store_info->mem_addr = get_addr (XEXP (mem, 0));
store_info->cse_base = base;
- store_info->positions_needed = lowpart_bitmask (width);
+ if (width > HOST_BITS_PER_WIDE_INT)
+ {
+ store_info->is_large = true;
+ store_info->positions_needed.large.count = 0;
+ store_info->positions_needed.large.bitmap = BITMAP_ALLOC (NULL);
+ }
+ else
+ {
+ store_info->is_large = false;
+ store_info->positions_needed.small_bitmask = lowpart_bitmask (width);
+ }
store_info->group_id = group_id;
store_info->begin = offset;
store_info->end = offset + width;
store_info->is_set = GET_CODE (body) == SET;
+ store_info->rhs = rhs;
+ store_info->const_rhs = const_rhs;
+ store_info->redundant_reason = redundant_reason;
- if (store_info->is_set
- /* No place to keep the value after ra. */
- && !reload_completed
- && (REG_P (SET_SRC (body))
- || GET_CODE (SET_SRC (body)) == SUBREG
- || CONSTANT_P (SET_SRC (body)))
- /* Sometimes the store and reload is used for truncation and
- rounding. */
- && !(FLOAT_MODE_P (GET_MODE (mem)) && (flag_float_store)))
- store_info->rhs = SET_SRC (body);
- else
- store_info->rhs = NULL;
-
/* If this is a clobber, we return 0. We will only be able to
delete this insn if there is only one store USED store, but we
can use the clobber to delete other stores earlier. */
static rtx
find_shift_sequence (int access_size,
store_info_t store_info,
- read_info_t read_info,
- int shift,
- bool speed)
+ enum machine_mode read_mode,
+ int shift, bool speed, bool require_cst)
{
enum machine_mode store_mode = GET_MODE (store_info->mem);
- enum machine_mode read_mode = GET_MODE (read_info->mem);
enum machine_mode new_mode;
rtx read_reg = NULL;
/* If a constant was stored into memory, try to simplify it here,
otherwise the cost of the shift might preclude this optimization
e.g. at -Os, even when no actual shift will be needed. */
- if (CONSTANT_P (store_info->rhs))
+ if (store_info->const_rhs)
{
unsigned int byte = subreg_lowpart_offset (new_mode, store_mode);
- rtx ret = simplify_subreg (new_mode, store_info->rhs, store_mode,
- byte);
+ rtx ret = simplify_subreg (new_mode, store_info->const_rhs,
+ store_mode, byte);
if (ret && CONSTANT_P (ret))
{
ret = simplify_const_binary_operation (LSHIFTRT, new_mode,
}
}
+ if (require_cst)
+ return NULL_RTX;
+
/* Try a wider mode if truncating the store mode to NEW_MODE
requires a real instruction. */
if (GET_MODE_BITSIZE (new_mode) < GET_MODE_BITSIZE (store_mode)
}
}
+/* Helper function for replace_read and record_store.
+ Attempt to return a value stored in STORE_INFO, from READ_BEGIN
+ to one before READ_END bytes read in READ_MODE. Return NULL
+ if not successful. If REQUIRE_CST is true, return always constant. */
+
+static rtx
+get_stored_val (store_info_t store_info, enum machine_mode read_mode,
+ HOST_WIDE_INT read_begin, HOST_WIDE_INT read_end,
+ basic_block bb, bool require_cst)
+{
+ enum machine_mode store_mode = GET_MODE (store_info->mem);
+ int shift;
+ int access_size; /* In bytes. */
+ rtx read_reg;
+
+ /* 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 (store_mode == BLKmode)
+ shift = 0;
+ else if (BYTES_BIG_ENDIAN)
+ shift = store_info->end - read_end;
+ else
+ shift = read_begin - store_info->begin;
+
+ access_size = shift + GET_MODE_SIZE (read_mode);
+
+ /* From now on it is bits. */
+ shift *= BITS_PER_UNIT;
+
+ if (shift)
+ read_reg = find_shift_sequence (access_size, store_info, read_mode, shift,
+ optimize_bb_for_speed_p (bb),
+ require_cst);
+ else if (store_mode == BLKmode)
+ {
+ /* The store is a memset (addr, const_val, const_size). */
+ gcc_assert (CONST_INT_P (store_info->rhs));
+ store_mode = int_mode_for_mode (read_mode);
+ if (store_mode == BLKmode)
+ read_reg = NULL_RTX;
+ else if (store_info->rhs == const0_rtx)
+ read_reg = extract_low_bits (read_mode, store_mode, const0_rtx);
+ else if (GET_MODE_BITSIZE (store_mode) > HOST_BITS_PER_WIDE_INT
+ || BITS_PER_UNIT >= HOST_BITS_PER_WIDE_INT)
+ read_reg = NULL_RTX;
+ else
+ {
+ unsigned HOST_WIDE_INT c
+ = INTVAL (store_info->rhs)
+ & (((HOST_WIDE_INT) 1 << BITS_PER_UNIT) - 1);
+ int shift = BITS_PER_UNIT;
+ while (shift < HOST_BITS_PER_WIDE_INT)
+ {
+ c |= (c << shift);
+ shift <<= 1;
+ }
+ read_reg = GEN_INT (trunc_int_for_mode (c, store_mode));
+ read_reg = extract_low_bits (read_mode, store_mode, read_reg);
+ }
+ }
+ else if (store_info->const_rhs
+ && (require_cst
+ || GET_MODE_CLASS (read_mode) != GET_MODE_CLASS (store_mode)))
+ read_reg = extract_low_bits (read_mode, store_mode,
+ copy_rtx (store_info->const_rhs));
+ else
+ read_reg = extract_low_bits (read_mode, store_mode,
+ copy_rtx (store_info->rhs));
+ if (require_cst && read_reg && !CONSTANT_P (read_reg))
+ read_reg = NULL_RTX;
+ return read_reg;
+}
/* Take a sequence of:
A <- r1
static bool
replace_read (store_info_t store_info, insn_info_t store_insn,
- read_info_t read_info, insn_info_t read_insn, rtx *loc, bitmap regs_live)
+ read_info_t read_info, insn_info_t read_insn, rtx *loc,
+ bitmap regs_live)
{
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 insns, this_insn, read_reg;
+ basic_block bb;
if (!dbg_cnt (dse))
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;
-
/* Create a sequence of instructions to set up the read register.
This sequence goes immediately before the store and its result
is read by the load.
GET_MODE_NAME (read_mode), INSN_UID (read_insn->insn),
GET_MODE_NAME (store_mode), INSN_UID (store_insn->insn));
start_sequence ();
- if (shift)
- read_reg = find_shift_sequence (access_size, store_info, read_info, shift,
- optimize_bb_for_speed_p (BLOCK_FOR_INSN (read_insn->insn)));
- else
- read_reg = extract_low_bits (read_mode, store_mode,
- copy_rtx (store_info->rhs));
+ bb = BLOCK_FOR_INSN (read_insn->insn);
+ read_reg = get_stored_val (store_info,
+ read_mode, read_info->begin, read_info->end,
+ bb, false);
if (read_reg == NULL_RTX)
{
end_sequence ();
else
{
if (store_info->rhs
- && (offset >= store_info->begin)
- && (offset + width <= store_info->end))
- {
- unsigned HOST_WIDE_INT mask
- = (lowpart_bitmask (width)
- << (offset - store_info->begin));
-
- if ((store_info->positions_needed & mask) == mask
- && replace_read (store_info, i_ptr,
- read_info, insn_info, loc, bb_info->regs_live))
- return 0;
- }
+ && offset >= store_info->begin
+ && offset + width <= store_info->end
+ && all_positions_needed_p (store_info,
+ offset - store_info->begin,
+ width)
+ && replace_read (store_info, i_ptr, read_info,
+ insn_info, loc, bb_info->regs_live))
+ return 0;
+
/* The bases are the same, just see if the offsets
overlap. */
if ((offset < store_info->end)
if (store_info->rhs
&& store_info->group_id == -1
&& store_info->cse_base == base
- && (offset >= store_info->begin)
- && (offset + width <= store_info->end))
- {
- unsigned HOST_WIDE_INT mask
- = (lowpart_bitmask (width)
- << (offset - store_info->begin));
-
- if ((store_info->positions_needed & mask) == mask
- && replace_read (store_info, i_ptr,
- read_info, insn_info, loc, bb_info->regs_live))
- return 0;
- }
+ && offset >= store_info->begin
+ && offset + width <= store_info->end
+ && all_positions_needed_p (store_info,
+ offset - store_info->begin, width)
+ && replace_read (store_info, i_ptr, read_info, insn_info, loc,
+ bb_info->regs_live))
+ return 0;
if (!store_info->alias_set)
remove = canon_true_dependence (store_info->mem,
for_each_rtx (loc, check_mem_read_rtx, data);
}
+
+/* Get arguments passed to CALL_INSN. Return TRUE if successful.
+ So far it only handles arguments passed in registers. */
+
+static bool
+get_call_args (rtx call_insn, tree fn, rtx *args, int nargs)
+{
+ CUMULATIVE_ARGS args_so_far;
+ tree arg;
+ int idx;
+
+ INIT_CUMULATIVE_ARGS (args_so_far, TREE_TYPE (fn), NULL_RTX, 0, 3);
+
+ arg = TYPE_ARG_TYPES (TREE_TYPE (fn));
+ for (idx = 0;
+ arg != void_list_node && idx < nargs;
+ arg = TREE_CHAIN (arg), idx++)
+ {
+ enum machine_mode mode = TYPE_MODE (TREE_VALUE (arg));
+ rtx reg = FUNCTION_ARG (args_so_far, mode, NULL_TREE, 1), link, tmp;
+ if (!reg || !REG_P (reg) || GET_MODE (reg) != mode
+ || GET_MODE_CLASS (mode) != MODE_INT)
+ return false;
+
+ for (link = CALL_INSN_FUNCTION_USAGE (call_insn);
+ link;
+ link = XEXP (link, 1))
+ if (GET_CODE (XEXP (link, 0)) == USE)
+ {
+ args[idx] = XEXP (XEXP (link, 0), 0);
+ if (REG_P (args[idx])
+ && REGNO (args[idx]) == REGNO (reg)
+ && (GET_MODE (args[idx]) == mode
+ || (GET_MODE_CLASS (GET_MODE (args[idx])) == MODE_INT
+ && (GET_MODE_SIZE (GET_MODE (args[idx]))
+ <= UNITS_PER_WORD)
+ && (GET_MODE_SIZE (GET_MODE (args[idx]))
+ > GET_MODE_SIZE (mode)))))
+ break;
+ }
+ if (!link)
+ return false;
+
+ tmp = cselib_expand_value_rtx (args[idx], scratch, 5);
+ if (GET_MODE (args[idx]) != mode)
+ {
+ if (!tmp || !CONST_INT_P (tmp))
+ return false;
+ tmp = GEN_INT (trunc_int_for_mode (INTVAL (tmp), mode));
+ }
+ if (tmp)
+ args[idx] = tmp;
+
+ FUNCTION_ARG_ADVANCE (args_so_far, mode, NULL_TREE, 1);
+ }
+ if (arg != void_list_node || idx != nargs)
+ return false;
+ return true;
+}
+
+
/* Apply record_store to all candidate stores in INSN. Mark INSN
if some part of it is not a candidate store and assigns to a
non-register target. */
if (CALL_P (insn))
{
+ bool const_call;
+ tree memset_call = NULL_TREE;
+
insn_info->cannot_delete = true;
/* Const functions cannot do anything bad i.e. read memory,
however, they can read their parameters which may have
- been pushed onto the stack. */
- if (RTL_CONST_CALL_P (insn))
+ been pushed onto the stack.
+ memset and bzero don't read memory either. */
+ const_call = RTL_CONST_CALL_P (insn);
+ if (!const_call)
+ {
+ rtx call = PATTERN (insn);
+ if (GET_CODE (call) == PARALLEL)
+ call = XVECEXP (call, 0, 0);
+ if (GET_CODE (call) == SET)
+ call = SET_SRC (call);
+ if (GET_CODE (call) == CALL
+ && MEM_P (XEXP (call, 0))
+ && GET_CODE (XEXP (XEXP (call, 0), 0)) == SYMBOL_REF)
+ {
+ rtx symbol = XEXP (XEXP (call, 0), 0);
+ if (SYMBOL_REF_DECL (symbol)
+ && TREE_CODE (SYMBOL_REF_DECL (symbol)) == FUNCTION_DECL)
+ {
+ if ((DECL_BUILT_IN_CLASS (SYMBOL_REF_DECL (symbol))
+ == BUILT_IN_NORMAL
+ && (DECL_FUNCTION_CODE (SYMBOL_REF_DECL (symbol))
+ == BUILT_IN_MEMSET))
+ || SYMBOL_REF_DECL (symbol) == block_clear_fn)
+ memset_call = SYMBOL_REF_DECL (symbol);
+ }
+ }
+ }
+ if (const_call || memset_call)
{
insn_info_t i_ptr = active_local_stores;
insn_info_t last = NULL;
if (dump_file)
- fprintf (dump_file, "const call %d\n", INSN_UID (insn));
+ fprintf (dump_file, "%s call %d\n",
+ const_call ? "const" : "memset", INSN_UID (insn));
/* See the head comment of the frame_read field. */
if (reload_completed)
i_ptr = i_ptr->next_local_store;
}
+
+ if (memset_call)
+ {
+ rtx args[3];
+ if (get_call_args (insn, memset_call, args, 3)
+ && CONST_INT_P (args[1])
+ && CONST_INT_P (args[2])
+ && INTVAL (args[2]) > 0)
+ {
+ rtx mem = gen_rtx_MEM (BLKmode, args[0]);
+ set_mem_size (mem, args[2]);
+ body = gen_rtx_SET (VOIDmode, mem, args[1]);
+ mems_found += record_store (body, bb_info);
+ if (dump_file)
+ fprintf (dump_file, "handling memset as BLKmode store\n");
+ if (mems_found == 1)
+ {
+ insn_info->next_local_store = active_local_stores;
+ active_local_stores = insn_info;
+ }
+ }
+ }
}
else
fprintf (dump_file, "mems_found = %d, cannot_delete = %s\n",
mems_found, insn_info->cannot_delete ? "true" : "false");
- /* If we found some sets of mems, and the insn has not been marked
- cannot delete, add it into the active_local_stores so that it can
- be locally deleted if found dead. Otherwise mark it as cannot
- delete. This simplifies the processing later. */
- if (mems_found == 1 && !insn_info->cannot_delete)
+ /* If we found some sets of mems, add it into the active_local_stores so
+ that it can be locally deleted if found dead or used for
+ replace_read and redundant constant store elimination. Otherwise mark
+ it as cannot delete. This simplifies the processing later. */
+ if (mems_found == 1)
{
insn_info->next_local_store = active_local_stores;
active_local_stores = insn_info;
/* Skip the clobbers. */
while (!store_info->is_set)
store_info = store_info->next;
- if (store_info->alias_set)
+ if (store_info->alias_set && !i_ptr->cannot_delete)
delete_dead_store_insn (i_ptr);
else
if (store_info->group_id >= 0)
{
group_info_t group
= VEC_index (group_info_t, rtx_group_vec, store_info->group_id);
- if (group->frame_related)
+ if (group->frame_related && !i_ptr->cannot_delete)
delete_dead_store_insn (i_ptr);
}
while (ptr)
{
if (ptr->contains_cselib_groups)
- free_store_info (ptr);
+ {
+ store_info_t s_info = ptr->store_rec;
+ while (s_info && !s_info->is_set)
+ s_info = s_info->next;
+ if (s_info
+ && s_info->redundant_reason
+ && s_info->redundant_reason->insn
+ && !ptr->cannot_delete)
+ {
+ if (dump_file)
+ fprintf (dump_file, "Locally deleting insn %d "
+ "because insn %d stores the "
+ "same value and couldn't be "
+ "eliminated\n",
+ INSN_UID (ptr->insn),
+ INSN_UID (s_info->redundant_reason->insn));
+ delete_dead_store_insn (ptr);
+ }
+ if (s_info)
+ s_info->redundant_reason = NULL;
+ free_store_info (ptr);
+ }
+ else
+ {
+ store_info_t s_info;
+
+ /* Free at least positions_needed bitmaps. */
+ for (s_info = ptr->store_rec; s_info; s_info = s_info->next)
+ if (s_info->is_large)
+ {
+ BITMAP_FREE (s_info->positions_needed.large.bitmap);
+ s_info->is_large = false;
+ }
+ }
ptr = ptr->prev_insn;
}
/*----------------------------------------------------------------------------
Sixth step.
+ Delete stores made redundant by earlier stores (which store the same
+ value) that couldn't be eliminated.
+----------------------------------------------------------------------------*/
+
+static void
+dse_step6 (void)
+{
+ basic_block bb;
+
+ FOR_ALL_BB (bb)
+ {
+ bb_info_t bb_info = bb_table[bb->index];
+ insn_info_t insn_info = bb_info->last_insn;
+
+ while (insn_info)
+ {
+ /* There may have been code deleted by the dce pass run before
+ this phase. */
+ if (insn_info->insn
+ && INSN_P (insn_info->insn)
+ && !insn_info->cannot_delete)
+ {
+ store_info_t s_info = insn_info->store_rec;
+
+ while (s_info && !s_info->is_set)
+ s_info = s_info->next;
+ if (s_info
+ && s_info->redundant_reason
+ && s_info->redundant_reason->insn
+ && INSN_P (s_info->redundant_reason->insn))
+ {
+ rtx rinsn = s_info->redundant_reason->insn;
+ if (dump_file)
+ fprintf (dump_file, "Locally deleting insn %d "
+ "because insn %d stores the "
+ "same value and couldn't be "
+ "eliminated\n",
+ INSN_UID (insn_info->insn),
+ INSN_UID (rinsn));
+ delete_dead_store_insn (insn_info);
+ }
+ }
+ insn_info = insn_info->prev_insn;
+ }
+ }
+}
+\f
+/*----------------------------------------------------------------------------
+ Seventh step.
+
Destroy everything left standing.
----------------------------------------------------------------------------*/
static void
-dse_step6 (bool global_done)
+dse_step7 (bool global_done)
{
unsigned int i;
group_info_t group;
dse_step4 ();
dse_step5_spill ();
}
-
- dse_step6 (did_global);
+
+ dse_step6 ();
+ dse_step7 (did_global);
if (dump_file)
fprintf (dump_file, "dse: local deletions = %d, global deletions = %d, spill deletions = %d\n",
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