if (num_chains == 0 || num_chains >= MAX_NUM_CHAINS)
return false;
- /* Now convert CD chains into predicates */
- has_valid_pred = true;
-
/* Now convert the control dep chain into a set
of predicates. */
*preds = XCNEWVEC (VEC(use_pred_info_t, heap) *,
for (i = 0; i < num_chains; i++)
{
VEC(edge, heap) *one_cd_chain = dep_chains[i];
+
+ has_valid_pred = false;
for (j = 0; j < VEC_length (edge, one_cd_chain); j++)
{
gimple cond_stmt;
one_pred->cond = cond_stmt;
one_pred->invert = !!(e->flags & EDGE_FALSE_VALUE);
VEC_safe_push (use_pred_info_t, heap, (*preds)[i], one_pred);
+ has_valid_pred = true;
}
if (!has_valid_pred)
static inline bool
is_and_or_or (enum tree_code tc, tree typ)
{
- return (tc == TRUTH_AND_EXPR
- || tc == TRUTH_OR_EXPR
- || tc == BIT_IOR_EXPR
+ return (tc == BIT_IOR_EXPR
|| (tc == BIT_AND_EXPR
&& (typ == 0 || TREE_CODE (typ) == BOOLEAN_TYPE)));
}
code1 = norm_cond1->cond_code;
code2 = norm_cond2->cond_code;
- if (code1 == TRUTH_AND_EXPR || code1 == BIT_AND_EXPR)
+ if (code1 == BIT_AND_EXPR)
{
/* Both conditions are AND expressions. */
- if (code2 == TRUTH_AND_EXPR || code2 == BIT_AND_EXPR)
+ if (code2 == BIT_AND_EXPR)
return is_and_set_subset_of (norm_cond1, norm_cond2);
/* NORM_COND1 is an AND expression, and NORM_COND2 is an OR
expression. In this case, returns true if any subexpression
of NORM_COND1 is a subset of any subexpression of NORM_COND2. */
- else if (code2 == TRUTH_OR_EXPR || code2 == BIT_IOR_EXPR)
+ else if (code2 == BIT_IOR_EXPR)
{
size_t len1;
len1 = VEC_length (gimple, norm_cond1->conds);
}
}
/* NORM_COND1 is an OR expression */
- else if (code1 == TRUTH_OR_EXPR || code1 == BIT_IOR_EXPR)
+ else if (code1 == BIT_IOR_EXPR)
{
if (code2 != code1)
return false;
gcc_assert (VEC_length (gimple, norm_cond1->conds) == 1);
/* Conservatively returns false if NORM_COND1 is non-decomposible
and NORM_COND2 is an AND expression. */
- if (code2 == TRUTH_AND_EXPR || code2 == BIT_AND_EXPR)
+ if (code2 == BIT_AND_EXPR)
return false;
- if (code2 == TRUTH_OR_EXPR || code2 == BIT_IOR_EXPR)
+ if (code2 == BIT_IOR_EXPR)
return is_subset_of_any (VEC_index (gimple, norm_cond1->conds, 0),
norm_cond1->invert, norm_cond2, false);
return true;
}
+/* Comparison function used by qsort. It is used to
+ sort predicate chains to allow predicate
+ simplification. */
+
+static int
+pred_chain_length_cmp (const void *p1, const void *p2)
+{
+ use_pred_info_t i1, i2;
+ VEC(use_pred_info_t, heap) * const *chain1
+ = (VEC(use_pred_info_t, heap) * const *)p1;
+ VEC(use_pred_info_t, heap) * const *chain2
+ = (VEC(use_pred_info_t, heap) * const *)p2;
+
+ if (VEC_length (use_pred_info_t, *chain1)
+ != VEC_length (use_pred_info_t, *chain2))
+ return (VEC_length (use_pred_info_t, *chain1)
+ - VEC_length (use_pred_info_t, *chain2));
+
+ i1 = VEC_index (use_pred_info_t, *chain1, 0);
+ i2 = VEC_index (use_pred_info_t, *chain2, 0);
+
+ /* Allow predicates with similar prefix come together. */
+ if (!i1->invert && i2->invert)
+ return -1;
+ else if (i1->invert && !i2->invert)
+ return 1;
+
+ return gimple_uid (i1->cond) - gimple_uid (i2->cond);
+}
+
+/* x OR (!x AND y) is equivalent to x OR y.
+ This function normalizes x1 OR (!x1 AND x2) OR (!x1 AND !x2 AND x3)
+ into x1 OR x2 OR x3. PREDS is the predicate chains, and N is
+ the number of chains. Returns true if normalization happens. */
+
+static bool
+normalize_preds (VEC(use_pred_info_t, heap) **preds, size_t *n)
+{
+ size_t i, j, ll;
+ VEC(use_pred_info_t, heap) *pred_chain;
+ VEC(use_pred_info_t, heap) *x = 0;
+ use_pred_info_t xj = 0, nxj = 0;
+
+ if (*n < 2)
+ return false;
+
+ /* First sort the chains in ascending order of lengths. */
+ qsort (preds, *n, sizeof (void *), pred_chain_length_cmp);
+ pred_chain = preds[0];
+ ll = VEC_length (use_pred_info_t, pred_chain);
+ if (ll != 1)
+ {
+ if (ll == 2)
+ {
+ use_pred_info_t xx, yy, xx2, nyy;
+ VEC(use_pred_info_t, heap) *pred_chain2 = preds[1];
+ if (VEC_length (use_pred_info_t, pred_chain2) != 2)
+ return false;
+
+ /* See if simplification x AND y OR x AND !y is possible. */
+ xx = VEC_index (use_pred_info_t, pred_chain, 0);
+ yy = VEC_index (use_pred_info_t, pred_chain, 1);
+ xx2 = VEC_index (use_pred_info_t, pred_chain2, 0);
+ nyy = VEC_index (use_pred_info_t, pred_chain2, 1);
+ if (gimple_cond_lhs (xx->cond) != gimple_cond_lhs (xx2->cond)
+ || gimple_cond_rhs (xx->cond) != gimple_cond_rhs (xx2->cond)
+ || gimple_cond_code (xx->cond) != gimple_cond_code (xx2->cond)
+ || (xx->invert != xx2->invert))
+ return false;
+ if (gimple_cond_lhs (yy->cond) != gimple_cond_lhs (nyy->cond)
+ || gimple_cond_rhs (yy->cond) != gimple_cond_rhs (nyy->cond)
+ || gimple_cond_code (yy->cond) != gimple_cond_code (nyy->cond)
+ || (yy->invert == nyy->invert))
+ return false;
+
+ /* Now merge the first two chains. */
+ free (yy);
+ free (nyy);
+ free (xx2);
+ VEC_free (use_pred_info_t, heap, pred_chain);
+ VEC_free (use_pred_info_t, heap, pred_chain2);
+ pred_chain = 0;
+ VEC_safe_push (use_pred_info_t, heap, pred_chain, xx);
+ preds[0] = pred_chain;
+ for (i = 1; i < *n - 1; i++)
+ preds[i] = preds[i + 1];
+
+ preds[*n - 1] = 0;
+ *n = *n - 1;
+ }
+ else
+ return false;
+ }
+
+ VEC_safe_push (use_pred_info_t, heap, x,
+ VEC_index (use_pred_info_t, pred_chain, 0));
+
+ /* The loop extracts x1, x2, x3, etc from chains
+ x1 OR (!x1 AND x2) OR (!x1 AND !x2 AND x3) OR ... */
+ for (i = 1; i < *n; i++)
+ {
+ pred_chain = preds[i];
+ if (VEC_length (use_pred_info_t, pred_chain) != i + 1)
+ return false;
+
+ for (j = 0; j < i; j++)
+ {
+ xj = VEC_index (use_pred_info_t, x, j);
+ nxj = VEC_index (use_pred_info_t, pred_chain, j);
+
+ /* Check if nxj is !xj */
+ if (gimple_cond_lhs (xj->cond) != gimple_cond_lhs (nxj->cond)
+ || gimple_cond_rhs (xj->cond) != gimple_cond_rhs (nxj->cond)
+ || gimple_cond_code (xj->cond) != gimple_cond_code (nxj->cond)
+ || (xj->invert == nxj->invert))
+ return false;
+ }
+
+ VEC_safe_push (use_pred_info_t, heap, x,
+ VEC_index (use_pred_info_t, pred_chain, i));
+ }
+
+ /* Now normalize the pred chains using the extraced x1, x2, x3 etc. */
+ for (j = 0; j < *n; j++)
+ {
+ use_pred_info_t t;
+ xj = VEC_index (use_pred_info_t, x, j);
+
+ t = XNEW (struct use_pred_info);
+ *t = *xj;
+
+ VEC_replace (use_pred_info_t, x, j, t);
+ }
+
+ for (i = 0; i < *n; i++)
+ {
+ pred_chain = preds[i];
+ for (j = 0; j < VEC_length (use_pred_info_t, pred_chain); j++)
+ free (VEC_index (use_pred_info_t, pred_chain, j));
+ VEC_free (use_pred_info_t, heap, pred_chain);
+ pred_chain = 0;
+ /* A new chain. */
+ VEC_safe_push (use_pred_info_t, heap, pred_chain,
+ VEC_index (use_pred_info_t, x, i));
+ preds[i] = pred_chain;
+ }
+ return true;
+}
+
+
+
/* Computes the predicates that guard the use and checks
if the incoming paths that have empty (or possibly
empty) defintion can be pruned/filtered. The function returns
if (has_valid_preds)
{
+ bool normed;
if (dump_file)
dump_predicates (phi, num_def_preds, def_preds,
"Operand defs of phi ");
+
+ normed = normalize_preds (def_preds, &num_def_preds);
+ if (normed && dump_file)
+ {
+ fprintf (dump_file, "\nNormalized to\n");
+ dump_predicates (phi, num_def_preds, def_preds,
+ "Operand defs of phi ");
+ }
is_properly_guarded =
is_superset_of (def_preds, num_def_preds,
preds, num_preds);
return;
uninit_op = gimple_phi_arg_def (phi, MASK_FIRST_SET_BIT (uninit_opnds));
- warn_uninit (uninit_op,
+ warn_uninit (OPT_Wmaybe_uninitialized, uninit_op, SSA_NAME_VAR (uninit_op),
+ SSA_NAME_VAR (uninit_op),
"%qD may be used uninitialized in this function",
uninit_use_stmt);
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