static void allocate_bb_info (void);
static void free_bb_info (void);
-static void check_earlyclobber (rtx);
-static bool regclass_intersect (enum reg_class, enum reg_class);
+static bool check_earlyclobber (rtx);
static void mark_reg_use_for_earlyclobber_1 (rtx *, void *);
static int mark_reg_use_for_earlyclobber (rtx *, void *);
static void calculate_local_reg_bb_info (void);
static void set_up_bb_rts_numbers (void);
static int rpost_cmp (const void *, const void *);
-static bool modify_bb_reg_pav (basic_block, basic_block, bool);
static void calculate_reg_pav (void);
static void modify_reg_pav (void);
static void make_accurate_live_analysis (void);
/* Registers correspondingly killed (clobbered) and defined but not
killed afterward in the basic block. */
bitmap killed, avloc;
- /* Registers partially available correspondingly at the start and
- end of the basic block. */
- bitmap pavin, pavout;
+ /* Registers partially available and living (in other words whose
+ values were calculated and used) correspondingly at the start
+ and end of the basic block. */
+ bitmap live_pavin, live_pavout;
};
/* Macros for accessing data flow information of basic blocks. */
#define BB_INFO_BY_INDEX(N) BB_INFO (BASIC_BLOCK(N))
/* The function allocates the info structures of each basic block. It
- also initialized PAVIN and PAVOUT as if all hard registers were
- partially available. */
+ also initialized LIVE_PAVIN and LIVE_PAVOUT as if all hard
+ registers were partially available. */
static void
allocate_bb_info (void)
bb_info->earlyclobber = BITMAP_XMALLOC ();
bb_info->avloc = BITMAP_XMALLOC ();
bb_info->killed = BITMAP_XMALLOC ();
- bb_info->pavin = BITMAP_XMALLOC ();
- bb_info->pavout = BITMAP_XMALLOC ();
- bitmap_copy (bb_info->pavin, init);
- bitmap_copy (bb_info->pavout, init);
+ bb_info->live_pavin = BITMAP_XMALLOC ();
+ bb_info->live_pavout = BITMAP_XMALLOC ();
+ bitmap_copy (bb_info->live_pavin, init);
+ bitmap_copy (bb_info->live_pavout, init);
}
BITMAP_XFREE (init);
}
FOR_EACH_BB (bb)
{
bb_info = BB_INFO (bb);
- BITMAP_XFREE (bb_info->pavout);
- BITMAP_XFREE (bb_info->pavin);
+ BITMAP_XFREE (bb_info->live_pavout);
+ BITMAP_XFREE (bb_info->live_pavin);
BITMAP_XFREE (bb_info->killed);
BITMAP_XFREE (bb_info->avloc);
BITMAP_XFREE (bb_info->earlyclobber);
static varray_type earlyclobber_regclass;
-/* The function stores classes of registers which could be early
- clobbered in INSN. */
+/* This function finds and stores register classes that could be early
+ clobbered in INSN. If any earlyclobber classes are found, the function
+ returns TRUE, in all other cases it returns FALSE. */
-static void
+static bool
check_earlyclobber (rtx insn)
{
int opno;
+ bool found = false;
extract_insn (insn);
case ',':
if (amp_p && class != NO_REGS)
{
+ found = true;
for (i = VARRAY_ACTIVE_SIZE (earlyclobber_regclass) - 1;
i >= 0; i--)
if (VARRAY_INT (earlyclobber_regclass, i) == (int) class)
p += CONSTRAINT_LEN (c, p);
}
}
-}
-
-/* The function returns true if register classes C1 and C2 intersect. */
-static bool
-regclass_intersect (enum reg_class c1, enum reg_class c2)
-{
- HARD_REG_SET rs, zero;
-
- CLEAR_HARD_REG_SET (zero);
- COPY_HARD_REG_SET(rs, reg_class_contents [c1]);
- AND_HARD_REG_SET (rs, reg_class_contents [c2]);
- GO_IF_HARD_REG_EQUAL (zero, rs, yes);
- return true;
- yes:
- return false;
+ return found;
}
/* The function checks that pseudo-register *X has a class
intersecting with the class of pseudo-register could be early
- clobbered in the same insn. */
+ clobbered in the same insn.
+ This function is a no-op if earlyclobber_regclass is empty. */
static int
mark_reg_use_for_earlyclobber (rtx *x, void *data ATTRIBUTE_UNUSED)
pref_class = reg_preferred_class (regno);
alt_class = reg_alternate_class (regno);
for (i = VARRAY_ACTIVE_SIZE (earlyclobber_regclass) - 1; i >= 0; i--)
- if (regclass_intersect (VARRAY_INT (earlyclobber_regclass, i),
- pref_class)
+ if (reg_classes_intersect_p (VARRAY_INT (earlyclobber_regclass, i),
+ pref_class)
|| (VARRAY_INT (earlyclobber_regclass, i) != NO_REGS
- && regclass_intersect (VARRAY_INT (earlyclobber_regclass, i),
- alt_class)))
+ && reg_classes_intersect_p (VARRAY_INT (earlyclobber_regclass,
+ i),
+ alt_class)))
{
bitmap_set_bit (bb_info->earlyclobber, regno);
break;
if (INSN_P (insn))
{
note_stores (PATTERN (insn), mark_reg_change, bb);
- check_earlyclobber (insn);
- note_uses (&PATTERN (insn), mark_reg_use_for_earlyclobber_1, bb);
+ if (check_earlyclobber (insn))
+ note_uses (&PATTERN (insn), mark_reg_use_for_earlyclobber_1, bb);
}
}
}
return BB_INFO (b2)->rts_number - BB_INFO (b1)->rts_number;
}
-/* The function calculates partial availability of registers. The
- function calculates partial availability at the end of basic block
- BB by propagating partial availability at end of predecessor basic
- block PRED. The function returns true if the partial availability
- at the end of BB has been changed or if CHANGED_P. We have the
- following equations:
+/* Temporary bitmap used for live_pavin, live_pavout calculation. */
+static bitmap temp_bitmap;
- bb.pavin = empty for entry block | union (pavout of predecessors)
- bb.pavout = union (bb.pavin - b.killed, bb.avloc) */
+/* The function calculates partial register availability according to
+ the following equations:
-static bool
-modify_bb_reg_pav (basic_block bb, basic_block pred, bool changed_p)
-{
- struct bb_info *bb_info;
- bitmap bb_pavin, bb_pavout;
-
- bb_info = BB_INFO (bb);
- bb_pavin = bb_info->pavin;
- bb_pavout = bb_info->pavout;
- if (pred->index != ENTRY_BLOCK)
- bitmap_ior_into (bb_pavin, BB_INFO (pred)->pavout);
- changed_p |= bitmap_ior_and_compl (bb_pavout, bb_info->avloc,
- bb_pavin, bb_info->killed);
- return changed_p;
-}
-
-/* The function calculates partial register availability. */
+ bb.live_pavin
+ = empty for entry block
+ | union (live_pavout of predecessors) & global_live_at_start
+ bb.live_pavout = union (bb.live_pavin - bb.killed, bb.avloc)
+ & global_live_at_end */
static void
calculate_reg_pav (void)
{
basic_block bb, succ;
edge e;
- bool changed_p;
int i, nel;
varray_type bbs, new_bbs, temp;
basic_block *bb_array;
VARRAY_BB_INIT (bbs, n_basic_blocks, "basic blocks");
VARRAY_BB_INIT (new_bbs, n_basic_blocks, "basic blocks for the next iter.");
+ temp_bitmap = BITMAP_XMALLOC ();
FOR_EACH_BB (bb)
{
VARRAY_PUSH_BB (bbs, bb);
for (i = 0; i < nel; i++)
{
edge_iterator ei;
-
+ struct bb_info *bb_info;
+ bitmap bb_live_pavin, bb_live_pavout;
+
bb = bb_array [i];
- changed_p = 0;
+ bb_info = BB_INFO (bb);
+ bb_live_pavin = bb_info->live_pavin;
+ bb_live_pavout = bb_info->live_pavout;
FOR_EACH_EDGE (e, ei, bb->preds)
- changed_p = modify_bb_reg_pav (bb, e->src, changed_p);
- if (changed_p)
- FOR_EACH_EDGE (e, ei, bb->succs)
- {
- succ = e->dest;
- if (succ->index != EXIT_BLOCK && !TEST_BIT (wset, succ->index))
- {
- SET_BIT (wset, succ->index);
- VARRAY_PUSH_BB (new_bbs, succ);
- }
- }
+ {
+ basic_block pred = e->src;
+
+ if (pred->index != ENTRY_BLOCK)
+ bitmap_ior_into (bb_live_pavin, BB_INFO (pred)->live_pavout);
+ }
+ bitmap_and_into (bb_live_pavin, bb->global_live_at_start);
+ bitmap_ior_and_compl (temp_bitmap, bb_info->avloc,
+ bb_live_pavin, bb_info->killed);
+ bitmap_and_into (temp_bitmap, bb->global_live_at_end);
+ if (! bitmap_equal_p (temp_bitmap, bb_live_pavout))
+ {
+ bitmap_copy (bb_live_pavout, temp_bitmap);
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ succ = e->dest;
+ if (succ->index != EXIT_BLOCK
+ && !TEST_BIT (wset, succ->index))
+ {
+ SET_BIT (wset, succ->index);
+ VARRAY_PUSH_BB (new_bbs, succ);
+ }
+ }
+ }
}
temp = bbs;
bbs = new_bbs;
VARRAY_POP_ALL (new_bbs);
}
sbitmap_free (wset);
+ BITMAP_XFREE (temp_bitmap);
}
/* The function modifies partial availability information for two
insn if the pseudo-register is used first time in given BB
and not lived at the BB start. To prevent this we don't
change life information for such pseudo-registers. */
- bitmap_ior_into (bb_info->pavin, bb_info->earlyclobber);
+ bitmap_ior_into (bb_info->live_pavin, bb_info->earlyclobber);
#ifdef STACK_REGS
/* We can not use the same stack register for uninitialized
pseudo-register and another living pseudo-register because if the
uninitialized pseudo-register dies, subsequent pass reg-stack
will be confused (it will believe that the other register
dies). */
- bitmap_ior_into (bb_info->pavin, stack_regs);
+ bitmap_ior_into (bb_info->live_pavin, stack_regs);
#endif
}
#ifdef STACK_REGS
/* The following function makes live information more accurate by
modifying global_live_at_start and global_live_at_end of basic
- blocks. After the function call a register lives at a program
- point only if it is initialized on a path from CFG entry to the
- program point. The standard GCC life analysis permits registers to
- live uninitialized. */
+ blocks.
+
+ The standard GCC life analysis permits registers to live
+ uninitialized, for example:
+
+ R is never used
+ .....
+ Loop:
+ R is defined
+ ...
+ R is used.
+
+ With normal life_analysis, R would be live before "Loop:".
+ The result is that R causes many interferences that do not
+ serve any purpose.
+
+ After the function call a register lives at a program point
+ only if it is initialized on a path from CFG entry to the
+ program point. */
static void
make_accurate_live_analysis (void)
{
bb_info = BB_INFO (bb);
- bitmap_and_into (bb->global_live_at_start, bb_info->pavin);
- bitmap_and_into (bb->global_live_at_end, bb_info->pavout);
+ bitmap_and_into (bb->global_live_at_start, bb_info->live_pavin);
+ bitmap_and_into (bb->global_live_at_end, bb_info->live_pavout);
}
free_bb_info ();
}
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