From 7eb3f1f7cab7f8ffc75b8010f619a76fba2808c0 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 23 Jun 2009 16:32:59 +0200
Subject: [PATCH] var-tracking.c (unshare_variable): Force initialized to be
VAR_INIT_STATUS_INITIALIZED unless flag_var_tracking_uninit.
* var-tracking.c (unshare_variable): Force initialized to
be VAR_INIT_STATUS_INITIALIZED unless flag_var_tracking_uninit.
(set_variable_part): Likewise.
(struct variable_union_info): Remove pos_src field.
(vui_vec, vui_allocated): New variables.
(variable_union): Pass VAR_INIT_STATUS_UNKNOWN to unshare_variable
unconditionally. Avoid XCVECNEW/free for every sorting, for dst_l
== 1 use a simpler sorting algorithm. Compute pos field right
away, don't fill in pos_src. For dst_l == 2 avoid qsort.
Avoid quadratic comparison if !flag_var_tracking_uninit.
(variable_canonicalize): Pass VAR_INIT_STATUS_UNKNOWN to
unshare_variable unconditionally.
(dataflow_set_different_2): Removed.
(dataflow_set_different): Don't traverse second hash table.
(compute_bb_dataflow): Pass VAR_INIT_STATUS_UNINITIALIZED
unconditionally to var_reg_set or var_mem_set.
(emit_notes_in_bb): Likewise.
(delete_variable_part): Pass VAR_INIT_STATUS_UNKNOWN to
unshare_variable.
(emit_note_insn_var_location): Don't set initialized to
VAR_INIT_STATUS_INITIALIZED early.
(vt_finalize): Free vui_vec if needed, clear vui_vec and
vui_allocated.
* rtl.c (rtx_equal_p): Don't implement on top of rtx_equal_p_cb.
From-SVN: r148852
---
gcc/ChangeLog | 25 ++++
gcc/rtl.c | 112 +++++++++++++++-
gcc/var-tracking.c | 328 +++++++++++++++++++++++++--------------------
3 files changed, 315 insertions(+), 150 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index bcb6209ab6d2..7ed384a59e7c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,30 @@
2009-06-23 Jakub Jelinek <jakub@redhat.com>
+ * var-tracking.c (unshare_variable): Force initialized to
+ be VAR_INIT_STATUS_INITIALIZED unless flag_var_tracking_uninit.
+ (set_variable_part): Likewise.
+ (struct variable_union_info): Remove pos_src field.
+ (vui_vec, vui_allocated): New variables.
+ (variable_union): Pass VAR_INIT_STATUS_UNKNOWN to unshare_variable
+ unconditionally. Avoid XCVECNEW/free for every sorting, for dst_l
+ == 1 use a simpler sorting algorithm. Compute pos field right
+ away, don't fill in pos_src. For dst_l == 2 avoid qsort.
+ Avoid quadratic comparison if !flag_var_tracking_uninit.
+ (variable_canonicalize): Pass VAR_INIT_STATUS_UNKNOWN to
+ unshare_variable unconditionally.
+ (dataflow_set_different_2): Removed.
+ (dataflow_set_different): Don't traverse second hash table.
+ (compute_bb_dataflow): Pass VAR_INIT_STATUS_UNINITIALIZED
+ unconditionally to var_reg_set or var_mem_set.
+ (emit_notes_in_bb): Likewise.
+ (delete_variable_part): Pass VAR_INIT_STATUS_UNKNOWN to
+ unshare_variable.
+ (emit_note_insn_var_location): Don't set initialized to
+ VAR_INIT_STATUS_INITIALIZED early.
+ (vt_finalize): Free vui_vec if needed, clear vui_vec and
+ vui_allocated.
+ * rtl.c (rtx_equal_p): Don't implement on top of rtx_equal_p_cb.
+
* tree-object-size.c (addr_object_size): Instead of checking
for non-NULL TREE_CHAIN of the FIELD_DECL check that there
are no FIELD_DECLs following it.
diff --git a/gcc/rtl.c b/gcc/rtl.c
index fa4dddd17908..6d68fe875610 100644
--- a/gcc/rtl.c
+++ b/gcc/rtl.c
@@ -335,7 +335,9 @@ int currently_expanding_to_rtl;
/* Same as rtx_equal_p, but call CB on each pair of rtx if CB is not NULL.
- When the callback returns true, we continue with the new pair. */
+ When the callback returns true, we continue with the new pair.
+ Whenever changing this function check if rtx_equal_p below doesn't need
+ changing as well. */
int
rtx_equal_p_cb (const_rtx x, const_rtx y, rtx_equal_p_callback_function cb)
@@ -453,12 +455,116 @@ rtx_equal_p_cb (const_rtx x, const_rtx y, rtx_equal_p_callback_function cb)
}
/* Return 1 if X and Y are identical-looking rtx's.
- This is the Lisp function EQUAL for rtx arguments. */
+ This is the Lisp function EQUAL for rtx arguments.
+ Whenever changing this function check if rtx_equal_p_cb above doesn't need
+ changing as well. */
int
rtx_equal_p (const_rtx x, const_rtx y)
{
- return rtx_equal_p_cb (x, y, NULL);
+ int i;
+ int j;
+ enum rtx_code code;
+ const char *fmt;
+
+ if (x == y)
+ return 1;
+ if (x == 0 || y == 0)
+ return 0;
+
+ code = GET_CODE (x);
+ /* Rtx's of different codes cannot be equal. */
+ if (code != GET_CODE (y))
+ return 0;
+
+ /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
+ (REG:SI x) and (REG:HI x) are NOT equivalent. */
+
+ if (GET_MODE (x) != GET_MODE (y))
+ return 0;
+
+ /* Some RTL can be compared nonrecursively. */
+ switch (code)
+ {
+ case REG:
+ return (REGNO (x) == REGNO (y));
+
+ case LABEL_REF:
+ return XEXP (x, 0) == XEXP (y, 0);
+
+ case SYMBOL_REF:
+ return XSTR (x, 0) == XSTR (y, 0);
+
+ case SCRATCH:
+ case CONST_DOUBLE:
+ case CONST_INT:
+ case CONST_FIXED:
+ return 0;
+
+ default:
+ break;
+ }
+
+ /* Compare the elements. If any pair of corresponding elements
+ fail to match, return 0 for the whole thing. */
+
+ fmt = GET_RTX_FORMAT (code);
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ switch (fmt[i])
+ {
+ case 'w':
+ if (XWINT (x, i) != XWINT (y, i))
+ return 0;
+ break;
+
+ case 'n':
+ case 'i':
+ if (XINT (x, i) != XINT (y, i))
+ return 0;
+ break;
+
+ case 'V':
+ case 'E':
+ /* Two vectors must have the same length. */
+ if (XVECLEN (x, i) != XVECLEN (y, i))
+ return 0;
+
+ /* And the corresponding elements must match. */
+ for (j = 0; j < XVECLEN (x, i); j++)
+ if (rtx_equal_p (XVECEXP (x, i, j), XVECEXP (y, i, j)) == 0)
+ return 0;
+ break;
+
+ case 'e':
+ if (rtx_equal_p (XEXP (x, i), XEXP (y, i)) == 0)
+ return 0;
+ break;
+
+ case 'S':
+ case 's':
+ if ((XSTR (x, i) || XSTR (y, i))
+ && (! XSTR (x, i) || ! XSTR (y, i)
+ || strcmp (XSTR (x, i), XSTR (y, i))))
+ return 0;
+ break;
+
+ case 'u':
+ /* These are just backpointers, so they don't matter. */
+ break;
+
+ case '0':
+ case 't':
+ break;
+
+ /* It is believed that rtx's at this level will never
+ contain anything but integers and other rtx's,
+ except for within LABEL_REFs and SYMBOL_REFs. */
+ default:
+ gcc_unreachable ();
+ }
+ }
+ return 1;
}
void
diff --git a/gcc/var-tracking.c b/gcc/var-tracking.c
index 79bdce6417f8..76354d791000 100644
--- a/gcc/var-tracking.c
+++ b/gcc/var-tracking.c
@@ -347,7 +347,6 @@ static void dataflow_set_union (dataflow_set *, dataflow_set *);
static bool variable_part_different_p (variable_part *, variable_part *);
static bool variable_different_p (variable, variable, bool);
static int dataflow_set_different_1 (void **, void *);
-static int dataflow_set_different_2 (void **, void *);
static bool dataflow_set_different (dataflow_set *, dataflow_set *);
static void dataflow_set_destroy (dataflow_set *);
@@ -878,6 +877,9 @@ unshare_variable (dataflow_set *set, variable var,
var->refcount--;
new_var->n_var_parts = var->n_var_parts;
+ if (! flag_var_tracking_uninit)
+ initialized = VAR_INIT_STATUS_INITIALIZED;
+
for (i = 0; i < var->n_var_parts; i++)
{
location_chain node;
@@ -1202,11 +1204,14 @@ struct variable_union_info
/* The sum of positions in the input chains. */
int pos;
- /* The position in the chains of SRC and DST dataflow sets. */
- int pos_src;
+ /* The position in the chain of DST dataflow set. */
int pos_dst;
};
+/* Buffer for location list sorting and its allocated size. */
+static struct variable_union_info *vui_vec;
+static int vui_allocated;
+
/* Compare function for qsort, order the structures by POS element. */
static int
@@ -1263,14 +1268,9 @@ variable_union (void **slot, void *data)
}
if (k < src->n_var_parts)
{
- enum var_init_status status = VAR_INIT_STATUS_UNKNOWN;
-
- if (! flag_var_tracking_uninit)
- status = VAR_INIT_STATUS_INITIALIZED;
-
if (dstp)
*dstp = (void *) src;
- unshare_variable (set, src, status);
+ unshare_variable (set, src, VAR_INIT_STATUS_UNKNOWN);
}
else
{
@@ -1311,13 +1311,7 @@ variable_union (void **slot, void *data)
if ((dst->refcount > 1 || shared_hash_shared (set->vars))
&& dst->n_var_parts != k)
- {
- enum var_init_status status = VAR_INIT_STATUS_UNKNOWN;
-
- if (! flag_var_tracking_uninit)
- status = VAR_INIT_STATUS_INITIALIZED;
- dst = unshare_variable (set, dst, status);
- }
+ dst = unshare_variable (set, dst, VAR_INIT_STATUS_UNKNOWN);
i = src->n_var_parts - 1;
j = dst->n_var_parts - 1;
@@ -1366,70 +1360,152 @@ variable_union (void **slot, void *data)
dst_l = 0;
for (node = dst->var_part[j].loc_chain; node; node = node->next)
dst_l++;
- vui = XCNEWVEC (struct variable_union_info, src_l + dst_l);
- /* Fill in the locations from DST. */
- for (node = dst->var_part[j].loc_chain, jj = 0; node;
- node = node->next, jj++)
+ if (dst_l == 1)
{
- vui[jj].lc = node;
- vui[jj].pos_dst = jj;
-
- /* Value larger than a sum of 2 valid positions. */
- vui[jj].pos_src = src_l + dst_l;
- }
-
- /* Fill in the locations from SRC. */
- n = dst_l;
- for (node = src->var_part[i].loc_chain, ii = 0; node;
- node = node->next, ii++)
- {
- /* Find location from NODE. */
- for (jj = 0; jj < dst_l; jj++)
- {
- if ((REG_P (vui[jj].lc->loc)
+ /* The most common case, much simpler, no qsort is needed. */
+ location_chain dstnode = dst->var_part[j].loc_chain;
+ dst->var_part[k].loc_chain = dstnode;
+ dst->var_part[k].offset = dst->var_part[j].offset;
+ node2 = dstnode;
+ for (node = src->var_part[i].loc_chain; node; node = node->next)
+ if (!((REG_P (dstnode->loc)
&& REG_P (node->loc)
- && REGNO (vui[jj].lc->loc) == REGNO (node->loc))
- || rtx_equal_p (vui[jj].lc->loc, node->loc))
+ && REGNO (dstnode->loc) == REGNO (node->loc))
+ || rtx_equal_p (dstnode->loc, node->loc)))
+ {
+ location_chain new_node;
+
+ /* Copy the location from SRC. */
+ new_node = (location_chain) pool_alloc (loc_chain_pool);
+ new_node->loc = node->loc;
+ new_node->init = node->init;
+ if (!node->set_src || MEM_P (node->set_src))
+ new_node->set_src = NULL;
+ else
+ new_node->set_src = node->set_src;
+ node2->next = new_node;
+ node2 = new_node;
+ }
+ node2->next = NULL;
+ }
+ else
+ {
+ if (src_l + dst_l > vui_allocated)
+ {
+ vui_allocated = MAX (vui_allocated * 2, src_l + dst_l);
+ vui_vec = XRESIZEVEC (struct variable_union_info, vui_vec,
+ vui_allocated);
+ }
+ vui = vui_vec;
+
+ /* Fill in the locations from DST. */
+ for (node = dst->var_part[j].loc_chain, jj = 0; node;
+ node = node->next, jj++)
+ {
+ vui[jj].lc = node;
+ vui[jj].pos_dst = jj;
+
+ /* Pos plus value larger than a sum of 2 valid positions. */
+ vui[jj].pos = jj + src_l + dst_l;
+ }
+
+ /* Fill in the locations from SRC. */
+ n = dst_l;
+ for (node = src->var_part[i].loc_chain, ii = 0; node;
+ node = node->next, ii++)
+ {
+ /* Find location from NODE. */
+ for (jj = 0; jj < dst_l; jj++)
{
- vui[jj].pos_src = ii;
- break;
+ if ((REG_P (vui[jj].lc->loc)
+ && REG_P (node->loc)
+ && REGNO (vui[jj].lc->loc) == REGNO (node->loc))
+ || rtx_equal_p (vui[jj].lc->loc, node->loc))
+ {
+ vui[jj].pos = jj + ii;
+ break;
+ }
+ }
+ if (jj >= dst_l) /* The location has not been found. */
+ {
+ location_chain new_node;
+
+ /* Copy the location from SRC. */
+ new_node = (location_chain) pool_alloc (loc_chain_pool);
+ new_node->loc = node->loc;
+ new_node->init = node->init;
+ if (!node->set_src || MEM_P (node->set_src))
+ new_node->set_src = NULL;
+ else
+ new_node->set_src = node->set_src;
+ vui[n].lc = new_node;
+ vui[n].pos_dst = src_l + dst_l;
+ vui[n].pos = ii + src_l + dst_l;
+ n++;
}
}
- if (jj >= dst_l) /* The location has not been found. */
+
+ if (dst_l == 2)
{
- location_chain new_node;
-
- /* Copy the location from SRC. */
- new_node = (location_chain) pool_alloc (loc_chain_pool);
- new_node->loc = node->loc;
- new_node->init = node->init;
- if (!node->set_src || MEM_P (node->set_src))
- new_node->set_src = NULL;
+ /* Special case still very common case. For dst_l == 2
+ all entries dst_l ... n-1 are sorted, with for i >= dst_l
+ vui[i].pos == i + src_l + dst_l. */
+ if (vui[0].pos > vui[1].pos)
+ {
+ /* Order should be 1, 0, 2... */
+ dst->var_part[k].loc_chain = vui[1].lc;
+ vui[1].lc->next = vui[0].lc;
+ if (n >= 3)
+ {
+ vui[0].lc->next = vui[2].lc;
+ vui[n - 1].lc->next = NULL;
+ }
+ else
+ vui[0].lc->next = NULL;
+ ii = 3;
+ }
else
- new_node->set_src = node->set_src;
- vui[n].lc = new_node;
- vui[n].pos_src = ii;
- vui[n].pos_dst = src_l + dst_l;
- n++;
+ {
+ dst->var_part[k].loc_chain = vui[0].lc;
+ if (n >= 3 && vui[2].pos < vui[1].pos)
+ {
+ /* Order should be 0, 2, 1, 3... */
+ vui[0].lc->next = vui[2].lc;
+ vui[2].lc->next = vui[1].lc;
+ if (n >= 4)
+ {
+ vui[1].lc->next = vui[3].lc;
+ vui[n - 1].lc->next = NULL;
+ }
+ else
+ vui[1].lc->next = NULL;
+ ii = 4;
+ }
+ else
+ {
+ /* Order should be 0, 1, 2... */
+ ii = 1;
+ vui[n - 1].lc->next = NULL;
+ }
+ }
+ for (; ii < n; ii++)
+ vui[ii - 1].lc->next = vui[ii].lc;
}
+ else
+ {
+ qsort (vui, n, sizeof (struct variable_union_info),
+ variable_union_info_cmp_pos);
+
+ /* Reconnect the nodes in sorted order. */
+ for (ii = 1; ii < n; ii++)
+ vui[ii - 1].lc->next = vui[ii].lc;
+ vui[n - 1].lc->next = NULL;
+ dst->var_part[k].loc_chain = vui[0].lc;
+ }
+
+ dst->var_part[k].offset = dst->var_part[j].offset;
}
-
- for (ii = 0; ii < src_l + dst_l; ii++)
- vui[ii].pos = vui[ii].pos_src + vui[ii].pos_dst;
-
- qsort (vui, n, sizeof (struct variable_union_info),
- variable_union_info_cmp_pos);
-
- /* Reconnect the nodes in sorted order. */
- for (ii = 1; ii < n; ii++)
- vui[ii - 1].lc->next = vui[ii].lc;
- vui[n - 1].lc->next = NULL;
-
- dst->var_part[k].loc_chain = vui[0].lc;
- dst->var_part[k].offset = dst->var_part[j].offset;
-
- free (vui);
i--;
j--;
}
@@ -1477,17 +1553,18 @@ variable_union (void **slot, void *data)
dst->var_part[k].cur_loc = NULL;
}
- for (i = 0; i < src->n_var_parts && i < dst->n_var_parts; i++)
- {
- location_chain node, node2;
- for (node = src->var_part[i].loc_chain; node; node = node->next)
- for (node2 = dst->var_part[i].loc_chain; node2; node2 = node2->next)
- if (rtx_equal_p (node->loc, node2->loc))
- {
- if (node->init > node2->init)
- node2->init = node->init;
- }
- }
+ if (flag_var_tracking_uninit)
+ for (i = 0; i < src->n_var_parts && i < dst->n_var_parts; i++)
+ {
+ location_chain node, node2;
+ for (node = src->var_part[i].loc_chain; node; node = node->next)
+ for (node2 = dst->var_part[i].loc_chain; node2; node2 = node2->next)
+ if (rtx_equal_p (node->loc, node2->loc))
+ {
+ if (node->init > node2->init)
+ node2->init = node->init;
+ }
+ }
/* Continue traversing the hash table. */
return 1;
@@ -1522,14 +1599,7 @@ variable_canonicalize (void **slot, void *data)
}
}
if (k < src->n_var_parts)
- {
- enum var_init_status status = VAR_INIT_STATUS_UNKNOWN;
-
- if (! flag_var_tracking_uninit)
- status = VAR_INIT_STATUS_INITIALIZED;
-
- unshare_variable (set, src, status);
- }
+ unshare_variable (set, src, VAR_INIT_STATUS_UNKNOWN);
return 1;
}
@@ -1650,34 +1720,6 @@ dataflow_set_different_1 (void **slot, void *data)
return 1;
}
-/* Compare variable *SLOT with the same variable in hash table DATA
- and set DATAFLOW_SET_DIFFERENT_VALUE if they are different. */
-
-static int
-dataflow_set_different_2 (void **slot, void *data)
-{
- htab_t htab = (htab_t) data;
- variable var1, var2;
-
- var1 = *(variable *) slot;
- var2 = (variable) htab_find_with_hash (htab, var1->decl,
- VARIABLE_HASH_VAL (var1->decl));
- if (!var2)
- {
- dataflow_set_different_value = true;
-
- /* Stop traversing the hash table. */
- return 0;
- }
-
- /* If both variables are defined they have been already checked for
- equivalence. */
- gcc_assert (!variable_different_p (var1, var2, false));
-
- /* Continue traversing the hash table. */
- return 1;
-}
-
/* Return true if dataflow sets OLD_SET and NEW_SET differ. */
static bool
@@ -1694,14 +1736,9 @@ dataflow_set_different (dataflow_set *old_set, dataflow_set *new_set)
htab_traverse (shared_hash_htab (old_set->vars), dataflow_set_different_1,
shared_hash_htab (new_set->vars));
- if (!dataflow_set_different_value)
- {
- /* We have compared the variables which are in both hash tables
- so now only check whether there are some variables in NEW_SET->VARS
- which are not in OLD_SET->VARS. */
- htab_traverse (shared_hash_htab (new_set->vars), dataflow_set_different_2,
- shared_hash_htab (old_set->vars));
- }
+ /* No need to traverse the second hashtab, if both have the same number
+ of elements and the second one had all entries found in the first one,
+ then it can't have any extra entries. */
return dataflow_set_different_value;
}
@@ -2215,15 +2252,11 @@ compute_bb_dataflow (basic_block bb)
case MO_USE:
{
rtx loc = VTI (bb)->mos[i].u.loc;
- enum var_init_status status = VAR_INIT_STATUS_UNINITIALIZED;
-
- if (! flag_var_tracking_uninit)
- status = VAR_INIT_STATUS_INITIALIZED;
if (REG_P (loc))
- var_reg_set (out, loc, status, NULL);
+ var_reg_set (out, loc, VAR_INIT_STATUS_UNINITIALIZED, NULL);
else if (MEM_P (loc))
- var_mem_set (out, loc, status, NULL);
+ var_mem_set (out, loc, VAR_INIT_STATUS_UNINITIALIZED, NULL);
}
break;
@@ -2262,10 +2295,12 @@ compute_bb_dataflow (basic_block bb)
if (! flag_var_tracking_uninit)
src_status = VAR_INIT_STATUS_INITIALIZED;
else
- src_status = find_src_status (in, set_src);
+ {
+ src_status = find_src_status (in, set_src);
- if (src_status == VAR_INIT_STATUS_UNKNOWN)
- src_status = find_src_status (out, set_src);
+ if (src_status == VAR_INIT_STATUS_UNKNOWN)
+ src_status = find_src_status (out, set_src);
+ }
set_src = find_src_set_src (in, set_src);
@@ -2609,6 +2644,9 @@ set_variable_part (dataflow_set *set, rtx loc, tree decl, HOST_WIDE_INT offset,
variable var;
void **slot = shared_hash_find_slot (set->vars, decl);
+ if (! flag_var_tracking_uninit)
+ initialized = VAR_INIT_STATUS_INITIALIZED;
+
if (!slot || !*slot)
{
if (!slot)
@@ -2815,10 +2853,8 @@ delete_variable_part (dataflow_set *set, rtx loc, tree decl,
&& REGNO (node->loc) == REGNO (loc))
|| rtx_equal_p (node->loc, loc))
{
- enum var_init_status status = VAR_INIT_STATUS_UNKNOWN;
- if (! flag_var_tracking_uninit)
- status = VAR_INIT_STATUS_INITIALIZED;
- var = unshare_variable (set, var, status);
+ var = unshare_variable (set, var,
+ VAR_INIT_STATUS_UNKNOWN);
break;
}
}
@@ -2893,9 +2929,6 @@ emit_note_insn_var_location (void **varp, void *data)
gcc_assert (var->decl);
- if (! flag_var_tracking_uninit)
- initialized = VAR_INIT_STATUS_INITIALIZED;
-
complete = true;
last_limit = 0;
n_var_parts = 0;
@@ -3147,14 +3180,11 @@ emit_notes_in_bb (basic_block bb)
case MO_USE:
{
rtx loc = VTI (bb)->mos[i].u.loc;
-
- enum var_init_status status = VAR_INIT_STATUS_UNINITIALIZED;
- if (! flag_var_tracking_uninit)
- status = VAR_INIT_STATUS_INITIALIZED;
+
if (REG_P (loc))
- var_reg_set (&set, loc, status, NULL);
+ var_reg_set (&set, loc, VAR_INIT_STATUS_UNINITIALIZED, NULL);
else
- var_mem_set (&set, loc, status, NULL);
+ var_mem_set (&set, loc, VAR_INIT_STATUS_UNINITIALIZED, NULL);
emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
}
@@ -3552,6 +3582,10 @@ vt_finalize (void)
free_alloc_pool (var_pool);
free_alloc_pool (loc_chain_pool);
free_alloc_pool (shared_hash_pool);
+ if (vui_vec)
+ free (vui_vec);
+ vui_vec = NULL;
+ vui_allocated = 0;
}
/* The entry point to variable tracking pass. */