\f
/* An obstack for our working variables. */
-static struct obstack gcse_obstack;
-
-struct reg_use {rtx reg_rtx; };
-
-/* Hash table of expressions. */
-
-struct expr
-{
- /* The expression (SET_SRC for expressions, PATTERN for assignments). */
- rtx expr;
- /* Index in the available expression bitmaps. */
- int bitmap_index;
- /* Next entry with the same hash. */
- struct expr *next_same_hash;
- /* List of available occurrence in basic blocks in the function.
- An "available occurrence" is one that is the last occurrence in the
- basic block and the operands are not modified by following statements in
- the basic block [including this insn]. */
- struct occr *avail_occr;
-};
+static struct obstack cprop_obstack;
/* Occurrence of an expression.
There is one per basic block. If a pattern appears more than once the
DEF_VEC_P (occr_t);
DEF_VEC_ALLOC_P (occr_t, heap);
-/* Expression and copy propagation hash tables.
+/* Hash table entry for an assignment expressions. */
+
+struct expr
+{
+ /* The expression (DEST := SRC). */
+ rtx dest;
+ rtx src;
+
+ /* Index in the available expression bitmaps. */
+ int bitmap_index;
+ /* Next entry with the same hash. */
+ struct expr *next_same_hash;
+ /* List of available occurrence in basic blocks in the function.
+ An "available occurrence" is one that is the last occurrence in the
+ basic block and the operands are not modified by following statements in
+ the basic block [including this insn]. */
+ struct occr *avail_occr;
+};
+
+/* Hash table for copy propagation expressions.
Each hash table is an array of buckets.
??? It is known that if it were an array of entries, structure elements
`next_same_hash' and `bitmap_index' wouldn't be necessary. However, it is
/* Bitmap containing one bit for each register in the program.
Used when performing GCSE to track which registers have been set since
- the start of the basic block. */
+ the start or end of the basic block while traversing that block. */
static regset reg_set_bitmap;
/* Various variables for statistics gathering. */
static int global_copy_prop_count;
\f
-#define GNEW(T) ((T *) gmalloc (sizeof (T)))
-
-#define GNEWVEC(T, N) ((T *) gmalloc (sizeof (T) * (N)))
-
-#define GNEWVAR(T, S) ((T *) gmalloc ((S)))
-
-#define GOBNEW(T) ((T *) gcse_alloc (sizeof (T)))
-#define GOBNEWVAR(T, S) ((T *) gcse_alloc ((S)))
-\f
-/* Cover function to xmalloc to record bytes allocated. */
-
-static void *
-gmalloc (size_t size)
-{
- bytes_used += size;
- return xmalloc (size);
-}
+#define GOBNEW(T) ((T *) cprop_alloc (sizeof (T)))
+#define GOBNEWVAR(T, S) ((T *) cprop_alloc ((S)))
/* Cover function to obstack_alloc. */
static void *
-gcse_alloc (unsigned long size)
+cprop_alloc (unsigned long size)
{
bytes_used += size;
- return obstack_alloc (&gcse_obstack, size);
-}
-
-/* Allocate memory for the reg/memory set tracking tables.
- This is called at the start of each pass. */
-
-static void
-alloc_gcse_mem (void)
-{
- /* Allocate vars to track sets of regs. */
- reg_set_bitmap = ALLOC_REG_SET (NULL);
-}
-
-/* Free memory allocated by alloc_gcse_mem. */
-
-static void
-free_gcse_mem (void)
-{
- FREE_REG_SET (reg_set_bitmap);
+ return obstack_alloc (&cprop_obstack, size);
}
\f
-struct reg_avail_info
-{
- basic_block last_bb;
- int last_set;
-};
-
-static struct reg_avail_info *reg_avail_info;
-static basic_block current_bb;
-
-/* Return nonzero if the operands of expression X are unchanged from
- INSN to the end of INSN's basic block. */
+/* Return nonzero if register X is unchanged from INSN to the end
+ of INSN's basic block. */
static int
-oprs_available_p (const_rtx x, const_rtx insn)
+reg_available_p (const_rtx x, const_rtx insn ATTRIBUTE_UNUSED)
{
- int i, j;
- enum rtx_code code;
- const char *fmt;
-
- if (x == 0)
- return 1;
-
- code = GET_CODE (x);
- switch (code)
- {
- case REG:
- {
- struct reg_avail_info *info = ®_avail_info[REGNO (x)];
-
- if (info->last_bb != current_bb)
- return 1;
- return info->last_set < DF_INSN_LUID (insn);
- }
-
- case PRE_DEC:
- case PRE_INC:
- case POST_DEC:
- case POST_INC:
- case PRE_MODIFY:
- case POST_MODIFY:
- return 0;
-
- case PC:
- case CC0: /*FIXME*/
- case CONST:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_FIXED:
- case CONST_VECTOR:
- case SYMBOL_REF:
- case LABEL_REF:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- return 1;
-
- default:
- break;
- }
-
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- if (! oprs_available_p (XEXP (x, i), insn))
- return 0;
- }
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- if (! oprs_available_p (XVECEXP (x, i, j), insn))
- return 0;
- }
-
- return 1;
+ return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
}
/* Hash a set of register REGNO.
return hash % hash_table_size;
}
-/* Return nonzero if exp1 is equivalent to exp2. */
-
-static int
-expr_equiv_p (const_rtx x, const_rtx y)
-{
- return exp_equiv_p (x, y, 0, true);
-}
-
-/* Insert pattern X in INSN in the hash table.
- X is a SET of a reg to either another reg or a constant.
- If it is already present, record it as the last occurrence in INSN's
- basic block. */
+/* Insert assignment DEST:=SET from INSN in the hash table.
+ DEST is a register and SET is a register or a suitable constant.
+ If the assignment is already present in the table, record it as
+ the last occurrence in INSN's basic block. */
static void
-insert_set_in_table (rtx x, rtx insn, struct hash_table_d *table)
+insert_set_in_table (rtx dest, rtx src, rtx insn, struct hash_table_d *table)
{
- int found;
+ bool found = false;
unsigned int hash;
struct expr *cur_expr, *last_expr = NULL;
struct occr *cur_occr;
- gcc_assert (GET_CODE (x) == SET && REG_P (SET_DEST (x)));
-
- hash = hash_set (REGNO (SET_DEST (x)), table->size);
+ hash = hash_set (REGNO (dest), table->size);
- cur_expr = table->table[hash];
- found = 0;
-
- while (cur_expr && 0 == (found = expr_equiv_p (cur_expr->expr, x)))
+ for (cur_expr = table->table[hash]; cur_expr;
+ cur_expr = cur_expr->next_same_hash)
{
- /* If the expression isn't found, save a pointer to the end of
- the list. */
+ if (dest == cur_expr->dest
+ && src == cur_expr->src)
+ {
+ found = true;
+ break;
+ }
last_expr = cur_expr;
- cur_expr = cur_expr->next_same_hash;
}
if (! found)
/* Set the fields of the expr element.
We must copy X because it can be modified when copy propagation is
performed on its operands. */
- cur_expr->expr = copy_rtx (x);
+ cur_expr->dest = copy_rtx (dest);
+ cur_expr->src = copy_rtx (src);
cur_expr->bitmap_index = table->n_elems++;
cur_expr->next_same_hash = NULL;
cur_expr->avail_occr = NULL;
}
}
-/* Determine whether the rtx X should be treated as a constant for
- the purposes of GCSE's constant propagation. */
+/* Determine whether the rtx X should be treated as a constant for CPROP.
+ Since X might be inserted more than once we have to take care that it
+ is sharable. */
static bool
-gcse_constant_p (const_rtx x)
+cprop_constant_p (const_rtx x)
{
- /* Consider a COMPARE of two integers constant. */
- if (GET_CODE (x) == COMPARE
- && CONST_INT_P (XEXP (x, 0))
- && CONST_INT_P (XEXP (x, 1)))
- return true;
-
- /* Consider a COMPARE of the same registers is a constant
- if they are not floating point registers. */
- if (GET_CODE(x) == COMPARE
- && REG_P (XEXP (x, 0)) && REG_P (XEXP (x, 1))
- && REGNO (XEXP (x, 0)) == REGNO (XEXP (x, 1))
- && ! FLOAT_MODE_P (GET_MODE (XEXP (x, 0)))
- && ! FLOAT_MODE_P (GET_MODE (XEXP (x, 1))))
- return true;
-
- /* Since X might be inserted more than once we have to take care that it
- is sharable. */
return CONSTANT_P (x) && (GET_CODE (x) != CONST || shared_const_p (x));
}
{
rtx src = SET_SRC (pat);
rtx dest = SET_DEST (pat);
- rtx note;
- if (REG_P (dest))
+ if (REG_P (dest)
+ && ! HARD_REGISTER_P (dest)
+ && reg_available_p (dest, insn)
+ && can_copy_p (GET_MODE (dest)))
{
- unsigned int regno = REGNO (dest);
- rtx tmp;
-
/* See if a REG_EQUAL note shows this equivalent to a simpler expression.
- This allows us to do a single GCSE pass and still eliminate
+ This allows us to do a single CPROP pass and still eliminate
redundant constants, addresses or other expressions that are
constructed with multiple instructions.
However, keep the original SRC if INSN is a simple reg-reg move. In
In this case, there will almost always be a REG_EQUAL note on the
insn that sets SRC. By recording the REG_EQUAL value here as SRC
- for INSN, we miss copy propagation opportunities and we perform the
- same PRE GCSE operation repeatedly on the same REG_EQUAL value if we
- do more than one PRE GCSE pass.
+ for INSN, we miss copy propagation opportunities.
Note that this does not impede profitable constant propagations. We
- "look through" reg-reg sets in lookup_avail_set. */
- note = find_reg_equal_equiv_note (insn);
+ "look through" reg-reg sets in lookup_set. */
+ rtx note = find_reg_equal_equiv_note (insn);
if (note != 0
&& REG_NOTE_KIND (note) == REG_EQUAL
&& !REG_P (src)
- && gcse_constant_p (XEXP (note, 0)))
+ && cprop_constant_p (XEXP (note, 0)))
src = XEXP (note, 0), pat = gen_rtx_SET (VOIDmode, dest, src);
/* Record sets for constant/copy propagation. */
- if (regno >= FIRST_PSEUDO_REGISTER
- && ((REG_P (src)
- && REGNO (src) >= FIRST_PSEUDO_REGISTER
- && can_copy_p (GET_MODE (dest))
- && REGNO (src) != regno)
- || gcse_constant_p (src))
- /* A copy is not available if its src or dest is subsequently
- modified. Here we want to search from INSN+1 on, but
- oprs_available_p searches from INSN on. */
- && (insn == BB_END (BLOCK_FOR_INSN (insn))
- || (tmp = next_nonnote_nondebug_insn (insn)) == NULL_RTX
- || BLOCK_FOR_INSN (tmp) != BLOCK_FOR_INSN (insn)
- || oprs_available_p (pat, tmp)))
- insert_set_in_table (pat, insn, table);
+ if ((REG_P (src)
+ && src != dest
+ && ! HARD_REGISTER_P (src)
+ && reg_available_p (src, insn))
+ || cprop_constant_p (src))
+ insert_set_in_table (dest, src, insn, table);
}
}
expr = flat_table[i];
fprintf (file, "Index %d (hash value %d)\n ",
expr->bitmap_index, hash_val[i]);
- print_rtl (file, expr->expr);
+ print_rtl (file, expr->dest);
+ fprintf (file, " := ");
+ print_rtl (file, expr->src);
fprintf (file, "\n");
}
free (hash_val);
}
-/* Record register first/last/block set information for REGNO in INSN.
-
- last_set records the last place in the block where the register
- is set and is used to compute "availability".
-
- last_bb records the block for which last_set is valid, as a quick
- test to invalidate it. */
-
-static void
-record_last_reg_set_info (rtx insn, int regno)
-{
- struct reg_avail_info *info = ®_avail_info[regno];
- int luid = DF_INSN_LUID (insn);
-
- info->last_set = luid;
- if (info->last_bb != current_bb)
- info->last_bb = current_bb;
-}
-
-/* Called from compute_hash_table via note_stores to handle one
- SET or CLOBBER in an insn. DATA is really the instruction in which
- the SET is taking place. */
-
+/* Record as unavailable all registers that are DEF operands of INSN. */
static void
-record_last_set_info (rtx dest, const_rtx setter ATTRIBUTE_UNUSED, void *data)
+make_set_regs_unavailable (rtx insn)
{
- rtx last_set_insn = (rtx) data;
+ struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+ df_ref *def_rec;
- if (GET_CODE (dest) == SUBREG)
- dest = SUBREG_REG (dest);
-
- if (REG_P (dest))
- record_last_reg_set_info (last_set_insn, REGNO (dest));
+ for (def_rec = DF_INSN_INFO_DEFS (insn_info); *def_rec; def_rec++)
+ SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (*def_rec));
}
/* Top level function to create an assignments hash table.
static void
compute_hash_table_work (struct hash_table_d *table)
{
- int i;
-
- /* Some working arrays used to track first and last set in each block. */
- reg_avail_info = GNEWVEC (struct reg_avail_info, max_reg_num ());
+ basic_block bb;
- for (i = 0; i < max_reg_num (); ++i)
- reg_avail_info[i].last_bb = NULL;
+ /* Allocate vars to track sets of regs. */
+ reg_set_bitmap = ALLOC_REG_SET (NULL);
- FOR_EACH_BB (current_bb)
+ FOR_EACH_BB (bb)
{
rtx insn;
- unsigned int regno;
- /* First pass over the instructions records information used to
- determine when registers and memory are first and last set. */
- FOR_BB_INSNS (current_bb, insn)
- {
+ /* Reset tables used to keep track of what's not yet invalid [since
+ the end of the block]. */
+ CLEAR_REG_SET (reg_set_bitmap);
+
+ /* Go over all insns from the last to the first. This is convenient
+ for tracking available registers, i.e. not set between INSN and
+ the end of the basic block BB. */
+ FOR_BB_INSNS_REVERSE (bb, insn)
+ {
+ /* Only real insns are interesting. */
if (!NONDEBUG_INSN_P (insn))
continue;
- if (CALL_P (insn))
- {
- for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
- if (TEST_HARD_REG_BIT (regs_invalidated_by_call, regno))
- record_last_reg_set_info (insn, regno);
- }
+ /* Record interesting sets from INSN in the hash table. */
+ hash_scan_insn (insn, table);
- note_stores (PATTERN (insn), record_last_set_info, insn);
+ /* Any registers set in INSN will make SETs above it not AVAIL. */
+ make_set_regs_unavailable (insn);
}
- /* Insert implicit sets in the hash table. */
- if (implicit_sets[current_bb->index] != NULL_RTX)
- hash_scan_set (implicit_sets[current_bb->index],
- BB_HEAD (current_bb), table);
-
- /* The next pass builds the hash table. */
- FOR_BB_INSNS (current_bb, insn)
- if (NONDEBUG_INSN_P (insn))
- hash_scan_insn (insn, table);
+ /* Insert implicit sets in the hash table, pretending they appear as
+ insns at the head of the basic block. */
+ if (implicit_sets[bb->index] != NULL_RTX)
+ hash_scan_set (implicit_sets[bb->index], BB_HEAD (bb), table);
}
- free (reg_avail_info);
- reg_avail_info = NULL;
+ FREE_REG_SET (reg_set_bitmap);
}
/* Allocate space for the set/expr hash TABLE.
??? Later take some measurements. */
table->size |= 1;
n = table->size * sizeof (struct expr *);
- table->table = GNEWVAR (struct expr *, n);
+ table->table = XNEWVAR (struct expr *, n);
}
/* Free things allocated by alloc_hash_table. */
expr = table->table[hash];
- while (expr && REGNO (SET_DEST (expr->expr)) != regno)
+ while (expr && REGNO (expr->dest) != regno)
expr = expr->next_same_hash;
return expr;
{
do
expr = expr->next_same_hash;
- while (expr && REGNO (SET_DEST (expr->expr)) != regno);
+ while (expr && REGNO (expr->dest) != regno);
return expr;
}
CLEAR_REG_SET (reg_set_bitmap);
}
-/* Return nonzero if the operands of X are not set before INSN in
- INSN's basic block. */
+/* Return nonzero if the register X has not been set yet [since the
+ start of the basic block containing INSN]. */
static int
-oprs_not_set_p (const_rtx x, const_rtx insn)
+reg_not_set_p (const_rtx x, const_rtx insn ATTRIBUTE_UNUSED)
{
- int i, j;
- enum rtx_code code;
- const char *fmt;
-
- if (x == 0)
- return 1;
-
- code = GET_CODE (x);
- switch (code)
- {
- case PC:
- case CC0:
- case CONST:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_FIXED:
- case CONST_VECTOR:
- case SYMBOL_REF:
- case LABEL_REF:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- return 1;
-
- case REG:
- return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
-
- default:
- break;
- }
-
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- /* If we are about to do the last recursive call
- needed at this level, change it into iteration.
- This function is called enough to be worth it. */
- if (i == 0)
- return oprs_not_set_p (XEXP (x, i), insn);
-
- if (! oprs_not_set_p (XEXP (x, i), insn))
- return 0;
- }
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- if (! oprs_not_set_p (XVECEXP (x, i, j), insn))
- return 0;
- }
-
- return 1;
-}
-
-/* Mark things set by a SET. */
-
-static void
-mark_set (rtx pat, rtx insn ATTRIBUTE_UNUSED)
-{
- rtx dest = SET_DEST (pat);
-
- while (GET_CODE (dest) == SUBREG
- || GET_CODE (dest) == ZERO_EXTRACT
- || GET_CODE (dest) == STRICT_LOW_PART)
- dest = XEXP (dest, 0);
-
- if (REG_P (dest))
- SET_REGNO_REG_SET (reg_set_bitmap, REGNO (dest));
-}
-
-/* Record things set by a CLOBBER. */
-
-static void
-mark_clobber (rtx pat, rtx insn ATTRIBUTE_UNUSED)
-{
- rtx clob = XEXP (pat, 0);
-
- while (GET_CODE (clob) == SUBREG || GET_CODE (clob) == STRICT_LOW_PART)
- clob = XEXP (clob, 0);
-
- if (REG_P (clob))
- SET_REGNO_REG_SET (reg_set_bitmap, REGNO (clob));
+ return ! REGNO_REG_SET_P (reg_set_bitmap, REGNO (x));
}
/* Record things set by INSN.
- This data is used by oprs_not_set_p. */
+ This data is used by reg_not_set_p. */
static void
mark_oprs_set (rtx insn)
{
- rtx pat = PATTERN (insn);
- int i;
-
- if (GET_CODE (pat) == SET)
- mark_set (pat, insn);
- else if (GET_CODE (pat) == PARALLEL)
- for (i = 0; i < XVECLEN (pat, 0); i++)
- {
- rtx x = XVECEXP (pat, 0, i);
+ struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+ df_ref *def_rec;
- if (GET_CODE (x) == SET)
- mark_set (x, insn);
- else if (GET_CODE (x) == CLOBBER)
- mark_clobber (x, insn);
- }
-
- else if (GET_CODE (pat) == CLOBBER)
- mark_clobber (pat, insn);
+ for (def_rec = DF_INSN_INFO_DEFS (insn_info); *def_rec; def_rec++)
+ SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (*def_rec));
}
\f
sbitmap_vector_free (cprop_avout);
}
-/* For each block, compute whether X is transparent. X is either an
- expression or an assignment [though we don't care which, for this context
- an assignment is treated as an expression]. For each block where an
- element of X is modified, set the INDX bit in BMAP. */
-
-static void
-compute_transp (const_rtx x, int indx, sbitmap *bmap)
-{
- int i, j;
- enum rtx_code code;
- const char *fmt;
-
- /* repeat is used to turn tail-recursion into iteration since GCC
- can't do it when there's no return value. */
- repeat:
-
- if (x == 0)
- return;
-
- code = GET_CODE (x);
- switch (code)
- {
- case REG:
- {
- df_ref def;
- for (def = DF_REG_DEF_CHAIN (REGNO (x));
- def;
- def = DF_REF_NEXT_REG (def))
- SET_BIT (bmap[DF_REF_BB (def)->index], indx);
- }
- return;
-
- case PC:
- case CC0: /*FIXME*/
- case CONST:
- case CONST_INT:
- case CONST_DOUBLE:
- case CONST_FIXED:
- case CONST_VECTOR:
- case SYMBOL_REF:
- case LABEL_REF:
- case ADDR_VEC:
- case ADDR_DIFF_VEC:
- return;
-
- default:
- break;
- }
-
- for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
- {
- if (fmt[i] == 'e')
- {
- /* If we are about to do the last recursive call
- needed at this level, change it into iteration.
- This function is called enough to be worth it. */
- if (i == 0)
- {
- x = XEXP (x, i);
- goto repeat;
- }
-
- compute_transp (XEXP (x, i), indx, bmap);
- }
- else if (fmt[i] == 'E')
- for (j = 0; j < XVECLEN (x, i); j++)
- compute_transp (XVECEXP (x, i, j), indx, bmap);
- }
-}
-
/* Compute the local properties of each recorded expression.
Local properties are those that are defined by the block, irrespective of
at least once and expression would contain the same value if the
computation was moved to the end of the block.
- TRANSP and COMP are destination sbitmaps for recording local properties.
- If NULL, then it is not necessary to compute or record that particular
- property.
-
- TRANSP is computed as ~TRANSP, since this is really cprop's ABSALTERED. */
+ TRANSP and COMP are destination sbitmaps for recording local properties. */
static void
compute_local_properties (sbitmap *transp, sbitmap *comp,
{
unsigned int i;
- /* Initialize any bitmaps that were passed in. */
- if (transp)
- {
- sbitmap_vector_zero (transp, last_basic_block);
- }
-
- if (comp)
- sbitmap_vector_zero (comp, last_basic_block);
+ /* Initialize the bitmaps that were passed in. */
+ sbitmap_vector_zero (transp, last_basic_block);
+ sbitmap_vector_zero (comp, last_basic_block);
for (i = 0; i < table->size; i++)
{
for (expr = table->table[i]; expr != NULL; expr = expr->next_same_hash)
{
int indx = expr->bitmap_index;
+ df_ref def;
struct occr *occr;
- /* The expression is transparent in this block if it is not killed.
- We start by assuming all are transparent [none are killed], and
- then reset the bits for those that are. */
- if (transp)
- compute_transp (expr->expr, indx, transp);
+ /* The expression is transparent in a block if it is not killed,
+ i.e. DEST and SRC are not set or clobbered in the block.
+ We start by assuming all are transparent [none are killed],
+ and then set the bits for those that are. */
+ for (def = DF_REG_DEF_CHAIN (REGNO (expr->dest));
+ def; def = DF_REF_NEXT_REG (def))
+ SET_BIT (transp[DF_REF_BB (def)->index], indx);
+ if (REG_P (expr->src))
+ for (def = DF_REG_DEF_CHAIN (REGNO (expr->src));
+ def; def = DF_REF_NEXT_REG (def))
+ SET_BIT (transp[DF_REF_BB (def)->index], indx);
/* The occurrences recorded in avail_occr are exactly those that
we want to set to nonzero in COMP. */
- if (comp)
- for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
- {
- SET_BIT (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
- }
+ for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
+ {
+ SET_BIT (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
+ }
}
}
}
/* Maximum number of register uses in an insn that we handle. */
#define MAX_USES 8
-/* Table of uses found in an insn.
+/* Table of uses (registers, both hard and pseudo) found in an insn.
Allocated statically to avoid alloc/free complexity and overhead. */
-static struct reg_use reg_use_table[MAX_USES];
+static rtx reg_use_table[MAX_USES];
/* Index into `reg_use_table' while building it. */
-static int reg_use_count;
+static unsigned reg_use_count;
/* Set up a list of register numbers used in INSN. The found uses are stored
in `reg_use_table'. `reg_use_count' is initialized to zero before entry,
if (reg_use_count == MAX_USES)
return;
- reg_use_table[reg_use_count].reg_rtx = x;
+ reg_use_table[reg_use_count] = x;
reg_use_count++;
}
if (set == 0)
break;
- gcc_assert (GET_CODE (set->expr) == SET);
-
- src = SET_SRC (set->expr);
+ src = set->src;
/* We know the set is available.
Now check that SRC is locally anticipatable (i.e. none of the
If the source operand changed, we may still use it for the next
iteration of this loop, but we may not use it for substitutions. */
- if (gcse_constant_p (src) || oprs_not_set_p (src, insn))
+ if (cprop_constant_p (src) || reg_not_set_p (src, insn))
set1 = set;
/* If the source of the set is anything except a register, then
edge e;
edge_iterator ei;
- for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ei_next (&ei))
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (e->dest != EXIT_BLOCK_PTR
&& BB_HEAD (e->dest) == JUMP_LABEL (jump))
{
static int
cprop_insn (rtx insn)
{
- struct reg_use *reg_used;
- int changed = 0;
+ unsigned i;
+ int changed = 0, changed_this_round;
rtx note;
- if (!INSN_P (insn))
- return 0;
-
+retry:
+ changed_this_round = 0;
reg_use_count = 0;
note_uses (&PATTERN (insn), find_used_regs, NULL);
- note = find_reg_equal_equiv_note (insn);
-
/* We may win even when propagating constants into notes. */
+ note = find_reg_equal_equiv_note (insn);
if (note)
find_used_regs (&XEXP (note, 0), NULL);
- for (reg_used = ®_use_table[0]; reg_use_count > 0;
- reg_used++, reg_use_count--)
+ for (i = 0; i < reg_use_count; i++)
{
- unsigned int regno = REGNO (reg_used->reg_rtx);
- rtx pat, src;
+ rtx reg_used = reg_use_table[i];
+ unsigned int regno = REGNO (reg_used);
+ rtx src;
struct expr *set;
/* If the register has already been set in this block, there's
nothing we can do. */
- if (! oprs_not_set_p (reg_used->reg_rtx, insn))
+ if (! reg_not_set_p (reg_used, insn))
continue;
/* Find an assignment that sets reg_used and is available
if (! set)
continue;
- pat = set->expr;
- /* ??? We might be able to handle PARALLELs. Later. */
- gcc_assert (GET_CODE (pat) == SET);
-
- src = SET_SRC (pat);
+ src = set->src;
/* Constant propagation. */
- if (gcse_constant_p (src))
+ if (cprop_constant_p (src))
{
- if (constprop_register (insn, reg_used->reg_rtx, src))
+ if (constprop_register (insn, reg_used, src))
{
- changed = 1;
+ changed_this_round = changed = 1;
global_const_prop_count++;
if (dump_file != NULL)
{
&& REGNO (src) >= FIRST_PSEUDO_REGISTER
&& REGNO (src) != regno)
{
- if (try_replace_reg (reg_used->reg_rtx, src, insn))
+ if (try_replace_reg (reg_used, src, insn))
{
- changed = 1;
+ changed_this_round = changed = 1;
global_copy_prop_count++;
if (dump_file != NULL)
{
}
/* The original insn setting reg_used may or may not now be
- deletable. We leave the deletion to flow. */
+ deletable. We leave the deletion to DCE. */
/* FIXME: If it turns out that the insn isn't deletable,
then we may have unnecessarily extended register lifetimes
and made things worse. */
}
}
+
+ /* If try_replace_reg simplified the insn, the regs found
+ by find_used_regs may not be valid anymore. Start over. */
+ if (changed_this_round)
+ goto retry;
}
if (changed && DEBUG_INSN_P (insn))
rtx this_rtx = l->loc;
rtx note;
- if (gcse_constant_p (this_rtx))
+ if (cprop_constant_p (this_rtx))
newcnst = this_rtx;
if (REG_P (this_rtx) && REGNO (this_rtx) >= FIRST_PSEUDO_REGISTER
/* Don't copy propagate if it has attached REG_EQUIV note.
{
basic_block bb;
rtx insn;
- struct reg_use *reg_used;
bool changed = false;
+ unsigned i;
cselib_init (0);
FOR_EACH_BB (bb)
if (note)
local_cprop_find_used_regs (&XEXP (note, 0), NULL);
- for (reg_used = ®_use_table[0]; reg_use_count > 0;
- reg_used++, reg_use_count--)
+ for (i = 0; i < reg_use_count; i++)
{
- if (do_local_cprop (reg_used->reg_rtx, insn))
+ if (do_local_cprop (reg_use_table[i], insn))
{
- changed = true;
+ if (!DEBUG_INSN_P (insn))
+ changed = true;
break;
}
}
if (INSN_DELETED_P (insn))
break;
}
- while (reg_use_count);
+ while (i < reg_use_count);
}
cselib_process_insn (insn);
}
return get_condition (jump, NULL, false, true);
}
-/* Check the comparison COND to see if we can safely form an implicit set from
- it. COND is either an EQ or NE comparison. */
+/* Check the comparison COND to see if we can safely form an implicit
+ set from it. */
static bool
implicit_set_cond_p (const_rtx cond)
{
- const enum machine_mode mode = GET_MODE (XEXP (cond, 0));
- const_rtx cst = XEXP (cond, 1);
+ enum machine_mode mode;
+ rtx cst;
+
+ /* COND must be either an EQ or NE comparison. */
+ if (GET_CODE (cond) != EQ && GET_CODE (cond) != NE)
+ return false;
+
+ /* The first operand of COND must be a pseudo-reg. */
+ if (! REG_P (XEXP (cond, 0))
+ || HARD_REGISTER_P (XEXP (cond, 0)))
+ return false;
+
+ /* The second operand of COND must be a suitable constant. */
+ mode = GET_MODE (XEXP (cond, 0));
+ cst = XEXP (cond, 1);
/* We can't perform this optimization if either operand might be or might
contain a signed zero. */
return 0;
}
- return gcse_constant_p (cst);
+ return cprop_constant_p (cst);
}
/* Find the implicit sets of a function. An "implicit set" is a constraint
function records the set patterns that are implicit at the start of each
basic block.
- FIXME: This would be more effective if critical edges are pre-split. As
- it is now, we can't record implicit sets for blocks that have
- critical successor edges. This results in missed optimizations
- and in more (unnecessary) work in cfgcleanup.c:thread_jump(). */
+ If an implicit set is found but the set is implicit on a critical edge,
+ this critical edge is split.
-static void
+ Return true if the CFG was modified, false otherwise. */
+
+static bool
find_implicit_sets (void)
{
basic_block bb, dest;
- unsigned int count;
rtx cond, new_rtx;
+ unsigned int count = 0;
+ bool edges_split = false;
+ size_t implicit_sets_size = last_basic_block + 10;
+
+ implicit_sets = XCNEWVEC (rtx, implicit_sets_size);
- count = 0;
FOR_EACH_BB (bb)
- /* Check for more than one successor. */
- if (EDGE_COUNT (bb->succs) > 1)
- {
- cond = fis_get_condition (BB_END (bb));
+ {
+ /* Check for more than one successor. */
+ if (EDGE_COUNT (bb->succs) <= 1)
+ continue;
- if (cond
- && (GET_CODE (cond) == EQ || GET_CODE (cond) == NE)
- && REG_P (XEXP (cond, 0))
- && REGNO (XEXP (cond, 0)) >= FIRST_PSEUDO_REGISTER
- && implicit_set_cond_p (cond))
- {
- dest = GET_CODE (cond) == EQ ? BRANCH_EDGE (bb)->dest
- : FALLTHRU_EDGE (bb)->dest;
+ cond = fis_get_condition (BB_END (bb));
- if (dest
- /* Record nothing for a critical edge. */
- && single_pred_p (dest)
- && dest != EXIT_BLOCK_PTR)
- {
- new_rtx = gen_rtx_SET (VOIDmode, XEXP (cond, 0),
- XEXP (cond, 1));
- implicit_sets[dest->index] = new_rtx;
- if (dump_file)
- {
- fprintf(dump_file, "Implicit set of reg %d in ",
- REGNO (XEXP (cond, 0)));
- fprintf(dump_file, "basic block %d\n", dest->index);
- }
- count++;
- }
- }
+ /* If no condition is found or if it isn't of a suitable form,
+ ignore it. */
+ if (! cond || ! implicit_set_cond_p (cond))
+ continue;
+
+ dest = GET_CODE (cond) == EQ
+ ? BRANCH_EDGE (bb)->dest : FALLTHRU_EDGE (bb)->dest;
+
+ /* If DEST doesn't go anywhere, ignore it. */
+ if (! dest || dest == EXIT_BLOCK_PTR)
+ continue;
+
+ /* We have found a suitable implicit set. Try to record it now as
+ a SET in DEST. If DEST has more than one predecessor, the edge
+ between BB and DEST is a critical edge and we must split it,
+ because we can only record one implicit set per DEST basic block. */
+ if (! single_pred_p (dest))
+ {
+ dest = split_edge (find_edge (bb, dest));
+ edges_split = true;
+ }
+
+ if (implicit_sets_size <= (size_t) dest->index)
+ {
+ size_t old_implicit_sets_size = implicit_sets_size;
+ implicit_sets_size *= 2;
+ implicit_sets = XRESIZEVEC (rtx, implicit_sets, implicit_sets_size);
+ memset (implicit_sets + old_implicit_sets_size, 0,
+ (implicit_sets_size - old_implicit_sets_size) * sizeof (rtx));
}
+ new_rtx = gen_rtx_SET (VOIDmode, XEXP (cond, 0),
+ XEXP (cond, 1));
+ implicit_sets[dest->index] = new_rtx;
+ if (dump_file)
+ {
+ fprintf(dump_file, "Implicit set of reg %d in ",
+ REGNO (XEXP (cond, 0)));
+ fprintf(dump_file, "basic block %d\n", dest->index);
+ }
+ count++;
+ }
+
if (dump_file)
fprintf (dump_file, "Found %d implicit sets\n", count);
+
+ /* Confess our sins. */
+ return edges_split;
}
/* Bypass conditional jumps. */
if (set == 0)
break;
- gcc_assert (GET_CODE (set->expr) == SET);
-
- src = SET_SRC (set->expr);
- if (gcse_constant_p (src))
+ src = set->src;
+ if (cprop_constant_p (src))
result = set;
if (! REG_P (src))
{
rtx insn, note;
edge e, edest;
- int i, change;
+ int change;
int may_be_loop_header;
unsigned removed_p;
+ unsigned i;
edge_iterator ei;
insn = (setcc != NULL) ? setcc : jump;
for (i = 0; i < reg_use_count; i++)
{
- struct reg_use *reg_used = ®_use_table[i];
- unsigned int regno = REGNO (reg_used->reg_rtx);
+ rtx reg_used = reg_use_table[i];
+ unsigned int regno = REGNO (reg_used);
basic_block dest, old_dest;
struct expr *set;
rtx src, new_rtx;
continue;
/* Check the data flow is valid after edge insertions. */
- if (e->insns.r && reg_killed_on_edge (reg_used->reg_rtx, e))
+ if (e->insns.r && reg_killed_on_edge (reg_used, e))
continue;
src = SET_SRC (pc_set (jump));
SET_DEST (PATTERN (setcc)),
SET_SRC (PATTERN (setcc)));
- new_rtx = simplify_replace_rtx (src, reg_used->reg_rtx,
- SET_SRC (set->expr));
+ new_rtx = simplify_replace_rtx (src, reg_used, set->src);
/* Jump bypassing may have already placed instructions on
edges of the CFG. We can't bypass an outgoing edge that
fprintf (dump_file, "JUMP-BYPASS: Proved reg %d "
"in jump_insn %d equals constant ",
regno, INSN_UID (jump));
- print_rtl (dump_file, SET_SRC (set->expr));
+ print_rtl (dump_file, set->src);
fprintf (dump_file, "\nBypass edge from %d->%d to %d\n",
e->src->index, old_dest->index, dest->index);
}
global_copy_prop_count = local_copy_prop_count = 0;
bytes_used = 0;
- gcc_obstack_init (&gcse_obstack);
- alloc_gcse_mem ();
+ gcc_obstack_init (&cprop_obstack);
/* Do a local const/copy propagation pass first. The global pass
only handles global opportunities.
FIXME: The global analysis would not get into infinite loops if it
would use the DF solver (via df_simple_dataflow) instead of
the solver implemented in this file. */
- if (local_cprop_pass ())
- {
- delete_unreachable_blocks ();
- df_analyze ();
- }
-
- /* Determine implicit sets. */
- implicit_sets = XCNEWVEC (rtx, last_basic_block);
- find_implicit_sets ();
+ changed |= local_cprop_pass ();
+ if (changed)
+ delete_unreachable_blocks ();
+
+ /* Determine implicit sets. This may change the CFG (split critical
+ edges if that exposes an implicit set).
+ Note that find_implicit_sets() does not rely on up-to-date DF caches
+ so that we do not have to re-run df_analyze() even if local CPROP
+ changed something.
+ ??? This could run earlier so that any uncovered implicit sets
+ sets could be exploited in local_cprop_pass() also. Later. */
+ changed |= find_implicit_sets ();
+
+ /* If local_cprop_pass() or find_implicit_sets() changed something,
+ run df_analyze() to bring all insn caches up-to-date, and to take
+ new basic blocks from edge splitting on the DF radar.
+ NB: This also runs the fast DCE pass, because execute_rtl_cprop
+ sets DF_LR_RUN_DCE. */
+ if (changed)
+ df_analyze ();
alloc_hash_table (&set_hash_table);
compute_hash_table (&set_hash_table);
alloc_cprop_mem (last_basic_block, set_hash_table.n_elems);
compute_cprop_data ();
+ /* Allocate vars to track sets of regs. */
+ reg_set_bitmap = ALLOC_REG_SET (NULL);
+
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb->next_bb, EXIT_BLOCK_PTR, next_bb)
{
/* Reset tables used to keep track of what's still valid [since
/* Keep track of everything modified by this insn. */
/* ??? Need to be careful w.r.t. mods done to INSN.
Don't call mark_oprs_set if we turned the
- insn into a NOTE. */
- if (! NOTE_P (insn))
+ insn into a NOTE, or deleted the insn. */
+ if (! NOTE_P (insn) && ! INSN_DELETED_P (insn))
mark_oprs_set (insn);
}
}
changed |= bypass_conditional_jumps ();
+
+ FREE_REG_SET (reg_set_bitmap);
free_cprop_mem ();
}
free_hash_table (&set_hash_table);
- free_gcse_mem ();
- obstack_free (&gcse_obstack, NULL);
+ obstack_free (&cprop_obstack, NULL);
if (dump_file)
{
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_df_finish | TODO_verify_rtl_sharing |
- TODO_dump_func |
TODO_verify_flow | TODO_ggc_collect /* todo_flags_finish */
}
};
-