DEF_VEC_P (occr_t);
DEF_VEC_ALLOC_P (occr_t, heap);
-/* Hash table entry for an assignment expressions. */
+/* Hash table entry for assignment expressions. */
struct expr
{
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]. */
+ basic block and whose operands are not modified by following statements
+ in the basic block [including this insn]. */
struct occr *avail_occr;
};
/* Array of implicit set patterns indexed by basic block index. */
static rtx *implicit_sets;
+/* Array of indexes of expressions for implicit set patterns indexed by basic
+ block index. In other words, implicit_set_indexes[i] is the bitmap_index
+ of the expression whose RTX is implicit_sets[i]. */
+static int *implicit_set_indexes;
+
/* Bitmap containing one bit for each register in the program.
Used when performing GCSE to track which registers have been set since
the start or end of the basic block while traversing that block. */
static int global_const_prop_count;
/* Number of global copies propagated. */
static int global_copy_prop_count;
-\f
#define GOBNEW(T) ((T *) cprop_alloc (sizeof (T)))
#define GOBNEWVAR(T, S) ((T *) cprop_alloc ((S)))
/* 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. */
+ the last occurrence in INSN's basic block.
+ IMPLICIT is true if it's an implicit set, false otherwise. */
static void
-insert_set_in_table (rtx dest, rtx src, rtx insn, struct hash_table_d *table)
+insert_set_in_table (rtx dest, rtx src, rtx insn, struct hash_table_d *table,
+ bool implicit)
{
bool found = false;
unsigned int hash;
cur_occr->next = cur_expr->avail_occr;
cur_expr->avail_occr = cur_occr;
}
+
+ /* Record bitmap_index of the implicit set in implicit_set_indexes. */
+ if (implicit)
+ implicit_set_indexes[BLOCK_FOR_INSN(insn)->index] = cur_expr->bitmap_index;
}
/* Determine whether the rtx X should be treated as a constant for CPROP.
return CONSTANT_P (x) && (GET_CODE (x) != CONST || shared_const_p (x));
}
-/* Scan pattern PAT of INSN and add an entry to the hash TABLE (set or
- expression one). */
+/* Scan SET present in INSN and add an entry to the hash TABLE.
+ IMPLICIT is true if it's an implicit set, false otherwise. */
static void
-hash_scan_set (rtx pat, rtx insn, struct hash_table_d *table)
+hash_scan_set (rtx set, rtx insn, struct hash_table_d *table, bool implicit)
{
- rtx src = SET_SRC (pat);
- rtx dest = SET_DEST (pat);
+ rtx src = SET_SRC (set);
+ rtx dest = SET_DEST (set);
if (REG_P (dest)
&& ! HARD_REGISTER_P (dest)
&& REG_NOTE_KIND (note) == REG_EQUAL
&& !REG_P (src)
&& cprop_constant_p (XEXP (note, 0)))
- src = XEXP (note, 0), pat = gen_rtx_SET (VOIDmode, dest, src);
+ src = XEXP (note, 0), set = gen_rtx_SET (VOIDmode, dest, src);
/* Record sets for constant/copy propagation. */
if ((REG_P (src)
&& ! HARD_REGISTER_P (src)
&& reg_available_p (src, insn))
|| cprop_constant_p (src))
- insert_set_in_table (dest, src, insn, table);
+ insert_set_in_table (dest, src, insn, table, implicit);
}
}
-/* Process INSN and add hash table entries as appropriate.
-
- Only available expressions that set a single pseudo-reg are recorded.
-
- Single sets in a PARALLEL could be handled, but it's an extra complication
- that isn't dealt with right now. The trick is handling the CLOBBERs that
- are also in the PARALLEL. Later.
-
- If SET_P is nonzero, this is for the assignment hash table,
- otherwise it is for the expression hash table. */
+/* Process INSN and add hash table entries as appropriate. */
static void
hash_scan_insn (rtx insn, struct hash_table_d *table)
what's been modified. */
if (GET_CODE (pat) == SET)
- hash_scan_set (pat, insn, table);
+ hash_scan_set (pat, insn, table, false);
else if (GET_CODE (pat) == PARALLEL)
for (i = 0; i < XVECLEN (pat, 0); i++)
{
rtx x = XVECEXP (pat, 0, i);
if (GET_CODE (x) == SET)
- hash_scan_set (x, insn, table);
+ hash_scan_set (x, insn, table, false);
}
}
+/* Dump the hash table TABLE to file FILE under the name NAME. */
+
static void
dump_hash_table (FILE *file, const char *name, struct hash_table_d *table)
{
}
/* Record as unavailable all registers that are DEF operands of INSN. */
+
static void
make_set_regs_unavailable (rtx insn)
{
SET_REGNO_REG_SET (reg_set_bitmap, DF_REF_REGNO (*def_rec));
}
-/* Top level function to create an assignments hash table.
+/* Top level function to create an assignment hash table.
Assignment entries are placed in the hash table if
- they are of the form (set (pseudo-reg) src),
/* 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);
+ hash_scan_set (implicit_sets[bb->index], BB_HEAD (bb), table, true);
}
FREE_REG_SET (reg_set_bitmap);
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
/* Compute copy/constant propagation working variables. */
/* Local properties of assignments. */
-static sbitmap *cprop_pavloc;
-static sbitmap *cprop_absaltered;
+static sbitmap *cprop_avloc;
+static sbitmap *cprop_kill;
/* Global properties of assignments (computed from the local properties). */
static sbitmap *cprop_avin;
static void
alloc_cprop_mem (int n_blocks, int n_sets)
{
- cprop_pavloc = sbitmap_vector_alloc (n_blocks, n_sets);
- cprop_absaltered = sbitmap_vector_alloc (n_blocks, n_sets);
+ cprop_avloc = sbitmap_vector_alloc (n_blocks, n_sets);
+ cprop_kill = sbitmap_vector_alloc (n_blocks, n_sets);
cprop_avin = sbitmap_vector_alloc (n_blocks, n_sets);
cprop_avout = sbitmap_vector_alloc (n_blocks, n_sets);
static void
free_cprop_mem (void)
{
- sbitmap_vector_free (cprop_pavloc);
- sbitmap_vector_free (cprop_absaltered);
+ sbitmap_vector_free (cprop_avloc);
+ sbitmap_vector_free (cprop_kill);
sbitmap_vector_free (cprop_avin);
sbitmap_vector_free (cprop_avout);
}
Local properties are those that are defined by the block, irrespective of
other blocks.
- An expression is transparent in a block if its operands are not modified
- in the block.
+ An expression is killed in a block if its operands, either DEST or SRC, are
+ modified in the block.
An expression is computed (locally available) in a block if it is computed
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. */
+ KILL and COMP are destination sbitmaps for recording local properties. */
static void
-compute_local_properties (sbitmap *transp, sbitmap *comp,
+compute_local_properties (sbitmap *kill, sbitmap *comp,
struct hash_table_d *table)
{
unsigned int i;
/* Initialize the bitmaps that were passed in. */
- sbitmap_vector_zero (transp, last_basic_block);
+ sbitmap_vector_zero (kill, last_basic_block);
sbitmap_vector_zero (comp, last_basic_block);
for (i = 0; i < table->size; i++)
df_ref def;
struct occr *occr;
- /* 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 each definition of the destination pseudo-reg, the expression
+ is killed in the block where the definition is. */
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);
+ SET_BIT (kill[DF_REF_BB (def)->index], indx);
+
+ /* If the source is a pseudo-reg, for each definition of the source,
+ the expression is killed in the block where the definition is. */
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);
+ SET_BIT (kill[DF_REF_BB (def)->index], indx);
/* The occurrences recorded in avail_occr are exactly those that
- we want to set to nonzero in COMP. */
+ are locally available in the block where they are. */
for (occr = expr->avail_occr; occr != NULL; occr = occr->next)
{
SET_BIT (comp[BLOCK_FOR_INSN (occr->insn)->index], indx);
static void
compute_cprop_data (void)
{
- compute_local_properties (cprop_absaltered, cprop_pavloc, &set_hash_table);
- compute_available (cprop_pavloc, cprop_absaltered,
- cprop_avout, cprop_avin);
+ basic_block bb;
+
+ compute_local_properties (cprop_kill, cprop_avloc, &set_hash_table);
+ compute_available (cprop_avloc, cprop_kill, cprop_avout, cprop_avin);
+
+ /* Merge implicit sets into CPROP_AVIN. They are always available at the
+ entry of their basic block. We need to do this because 1) implicit sets
+ aren't recorded for the local pass so they cannot be propagated within
+ their basic block by this pass and 2) the global pass would otherwise
+ propagate them only in the successors of their basic block. */
+ FOR_EACH_BB (bb)
+ {
+ int index = implicit_set_indexes[bb->index];
+ if (index != -1)
+ SET_BIT (cprop_avin[bb->index], index);
+ }
}
\f
/* Copy/constant propagation. */
}
}
-/* Try to replace all non-SET_DEST occurrences of FROM in INSN with TO.
- Returns nonzero is successful. */
+/* Try to replace all uses of FROM in INSN with TO.
+ Return nonzero if successful. */
static int
try_replace_reg (rtx from, rtx to, rtx insn)
simplify_replace_rtx (XEXP (note, 0), from, to));
if (!success && set && reg_mentioned_p (from, SET_SRC (set)))
{
- /* If above failed and this is a single set, try to simplify the source of
- the set given our substitution. We could perhaps try this for multiple
- SETs, but it probably won't buy us anything. */
+ /* If above failed and this is a single set, try to simplify the source
+ of the set given our substitution. We could perhaps try this for
+ multiple SETs, but it probably won't buy us anything. */
src = simplify_replace_rtx (SET_SRC (set), from, to);
if (!rtx_equal_p (src, SET_SRC (set))
note = set_unique_reg_note (insn, REG_EQUAL, copy_rtx (src));
}
+ if (set && MEM_P (SET_DEST (set)) && reg_mentioned_p (from, SET_DEST (set)))
+ {
+ /* Registers can also appear as uses in SET_DEST if it is a MEM.
+ We could perhaps try this for multiple SETs, but it probably
+ won't buy us anything. */
+ rtx dest = simplify_replace_rtx (SET_DEST (set), from, to);
+
+ if (!rtx_equal_p (dest, SET_DEST (set))
+ && validate_change (insn, &SET_DEST (set), dest, 0))
+ success = 1;
+ }
+
/* REG_EQUAL may get simplified into register.
We don't allow that. Remove that note. This code ought
not to happen, because previous code ought to synthesize
return success;
}
-/* Find a set of REGNOs that are available on entry to INSN's block. Returns
+/* Find a set of REGNOs that are available on entry to INSN's block. Return
NULL no such set is found. */
static struct expr *
JUMP_INSNS. JUMP must be a conditional jump. If SETCC is non-NULL
it is the instruction that immediately precedes JUMP, and must be a
single SET of a register. FROM is what we will try to replace,
- SRC is the constant we will try to substitute for it. Returns nonzero
+ SRC is the constant we will try to substitute for it. Return nonzero
if a change was made. */
static int
if (dump_file != NULL)
{
fprintf (dump_file,
- "GLOBAL CONST-PROP: Replacing reg %d in jump_insn %d with constant ",
- REGNO (from), INSN_UID (jump));
+ "GLOBAL CONST-PROP: Replacing reg %d in jump_insn %d with"
+ "constant ", REGNO (from), INSN_UID (jump));
print_rtl (dump_file, src);
fprintf (dump_file, "\n");
}
return 1;
}
-static bool
-constprop_register (rtx insn, rtx from, rtx to)
+/* Subroutine of cprop_insn that tries to propagate constants. FROM is what
+ we will try to replace, SRC is the constant we will try to substitute for
+ it and INSN is the instruction where this will be happening. */
+
+static int
+constprop_register (rtx from, rtx src, rtx insn)
{
rtx sset;
{
rtx dest = SET_DEST (sset);
if ((REG_P (dest) || CC0_P (dest))
- && cprop_jump (BLOCK_FOR_INSN (insn), insn, NEXT_INSN (insn), from, to))
+ && cprop_jump (BLOCK_FOR_INSN (insn), insn, NEXT_INSN (insn),
+ from, src))
return 1;
}
/* Handle normal insns next. */
- if (NONJUMP_INSN_P (insn)
- && try_replace_reg (from, to, insn))
+ if (NONJUMP_INSN_P (insn) && try_replace_reg (from, src, insn))
return 1;
/* Try to propagate a CONST_INT into a conditional jump.
Right now the insn in question must look like
(set (pc) (if_then_else ...)) */
else if (any_condjump_p (insn) && onlyjump_p (insn))
- return cprop_jump (BLOCK_FOR_INSN (insn), NULL, insn, from, to);
+ return cprop_jump (BLOCK_FOR_INSN (insn), NULL, insn, from, src);
return 0;
}
/* Perform constant and copy propagation on INSN.
- The result is nonzero if a change was made. */
+ Return nonzero if a change was made. */
static int
cprop_insn (rtx insn)
/* Constant propagation. */
if (cprop_constant_p (src))
{
- if (constprop_register (insn, reg_used, src))
+ if (constprop_register (reg_used, src, insn))
{
changed_this_round = changed = 1;
global_const_prop_count++;
if (dump_file != NULL)
{
- fprintf (dump_file, "GLOBAL CONST-PROP: Replacing reg %d in ", regno);
- fprintf (dump_file, "insn %d with constant ", INSN_UID (insn));
+ fprintf (dump_file,
+ "GLOBAL CONST-PROP: Replacing reg %d in ", regno);
+ fprintf (dump_file, "insn %d with constant ",
+ INSN_UID (insn));
print_rtl (dump_file, src);
fprintf (dump_file, "\n");
}
global_copy_prop_count++;
if (dump_file != NULL)
{
- fprintf (dump_file, "GLOBAL COPY-PROP: Replacing reg %d in insn %d",
+ fprintf (dump_file,
+ "GLOBAL COPY-PROP: Replacing reg %d in insn %d",
regno, INSN_UID (insn));
fprintf (dump_file, " with reg %d\n", REGNO (src));
}
|| ! MEM_P (XEXP (note, 0))))
newreg = this_rtx;
}
- if (newcnst && constprop_register (insn, x, newcnst))
+ if (newcnst && constprop_register (x, newcnst, insn))
{
if (dump_file != NULL)
{
static int bypass_last_basic_block;
/* Find a set of REGNO to a constant that is available at the end of basic
- block BB. Returns NULL if no such set is found. Based heavily upon
+ block BB. Return NULL if no such set is found. Based heavily upon
find_avail_set. */
static struct expr *
return result;
}
-
/* Subroutine of bypass_block that checks whether a pseudo is killed by
any of the instructions inserted on an edge. Jump bypassing places
condition code setters on CFG edges using insert_insn_on_edge. This
}
/* The irreducible loops created by redirecting of edges entering the
- loop from outside would decrease effectiveness of some of the following
- optimizations, so prevent this. */
+ loop from outside would decrease effectiveness of some of the
+ following optimizations, so prevent this. */
if (may_be_loop_header
&& !(e->flags & EDGE_DFS_BACK))
{
edges of the CFG. We can't bypass an outgoing edge that
has instructions associated with it, as these insns won't
get executed if the incoming edge is redirected. */
-
if (new_rtx == pc_rtx)
{
edest = FALLTHRU_EDGE (bb);
/* Avoid unification of the edge with other edges from original
branch. We would end up emitting the instruction on "both"
edges. */
-
if (dest && setcc && !CC0_P (SET_DEST (PATTERN (setcc)))
&& find_edge (e->src, dest))
dest = NULL;
/* Find basic blocks with more than one predecessor that only contain a
single conditional jump. If the result of the comparison is known at
compile-time from any incoming edge, redirect that edge to the
- appropriate target. Returns nonzero if a change was made.
+ appropriate target. Return nonzero if a change was made.
This function is now mis-named, because we also handle indirect jumps. */
return changed;
}
\f
-/* Return true if the graph is too expensive to optimize. PASS is the
+/* Return true if the graph is too expensive to optimize. PASS is the
optimization about to be performed. */
static bool
return false;
}
-
\f
/* Main function for the CPROP pass. */
static int
one_cprop_pass (void)
{
+ int i;
int changed = 0;
/* Return if there's nothing to do, or it is too expensive. */
if (changed)
df_analyze ();
+ /* Initialize implicit_set_indexes array. */
+ implicit_set_indexes = XNEWVEC (int, last_basic_block);
+ for (i = 0; i < last_basic_block; i++)
+ implicit_set_indexes[i] = -1;
+
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 ();
+ free (implicit_set_indexes);
+ implicit_set_indexes = NULL;
+
/* 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)
+ 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
the start of the block]. */
FREE_REG_SET (reg_set_bitmap);
free_cprop_mem ();
}
+ else
+ {
+ free (implicit_set_indexes);
+ implicit_set_indexes = NULL;
+ }
free_hash_table (&set_hash_table);
obstack_free (&cprop_obstack, NULL);
return changed;
}
-
\f
/* All the passes implemented in this file. Each pass has its
own gate and execute function, and at the end of the file a
OSDN Git Service
