/* An obstack for our working variables. */
static struct obstack cprop_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;
-};
-
/* Occurrence of an expression.
There is one per basic block. If a pattern appears more than once the
last appearance is used. */
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
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;
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. */
+ "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
&& ! HARD_REGISTER_P (src)
&& reg_available_p (src, insn))
|| cprop_constant_p (src))
- insert_set_in_table (pat, insn, table);
+ 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");
}
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;
}
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
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 (! reg_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 (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))
{
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);
}
FOR_EACH_BB (bb)
{
/* Check for more than one successor. */
- if (! EDGE_COUNT (bb->succs) > 1)
+ if (EDGE_COUNT (bb->succs) <= 1)
continue;
cond = fis_get_condition (BB_END (bb));
if (set == 0)
break;
- gcc_assert (GET_CODE (set->expr) == SET);
-
- src = SET_SRC (set->expr);
+ src = set->src;
if (cprop_constant_p (src))
result = set;
{
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);
}
/* 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);
}
}
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 */
}
};
-
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