??? We currently are very conservative and assume that a load might
trap even if a store doesn't (write-only memory). This probably is
- overly conservative. */
+ overly conservative.
-/* A hash-table of SSA_NAMEs, and in which basic block an MEM_REF
- through it was seen, which would constitute a no-trap region for
- same accesses. */
-struct name_to_bb
+ We currently support a special case that for !TREE_ADDRESSABLE automatic
+ variables, it could ignore whether something is a load or store because the
+ local stack should be always writable. */
+
+/* A hash-table of references (MEM_REF/ARRAY_REF/COMPONENT_REF), and in which
+ basic block an *_REF through it was seen, which would constitute a
+ no-trap region for same accesses.
+
+ Size is needed to support 2 MEM_REFs of different types, like
+ MEM<double>(s_1) and MEM<long>(s_1), which would compare equal with
+ OEP_ADDRESS_OF. */
+struct ref_to_bb
{
- unsigned int ssa_name_ver;
+ tree exp;
+ HOST_WIDE_INT size;
unsigned int phase;
- bool store;
- HOST_WIDE_INT offset, size;
basic_block bb;
};
/* Hashtable helpers. */
-struct ssa_names_hasher : free_ptr_hash <name_to_bb>
+struct refs_hasher : free_ptr_hash<ref_to_bb>
{
- static inline hashval_t hash (const name_to_bb *);
- static inline bool equal (const name_to_bb *, const name_to_bb *);
+ static inline hashval_t hash (const ref_to_bb *);
+ static inline bool equal (const ref_to_bb *, const ref_to_bb *);
};
/* Used for quick clearing of the hash-table when we see calls.
/* The hash function. */
inline hashval_t
-ssa_names_hasher::hash (const name_to_bb *n)
+refs_hasher::hash (const ref_to_bb *n)
{
- return n->ssa_name_ver ^ (((hashval_t) n->store) << 31)
- ^ (n->offset << 6) ^ (n->size << 3);
+ inchash::hash hstate;
+ inchash::add_expr (n->exp, hstate, OEP_ADDRESS_OF);
+ hstate.add_hwi (n->size);
+ return hstate.end ();
}
/* The equality function of *P1 and *P2. */
inline bool
-ssa_names_hasher::equal (const name_to_bb *n1, const name_to_bb *n2)
+refs_hasher::equal (const ref_to_bb *n1, const ref_to_bb *n2)
{
- return n1->ssa_name_ver == n2->ssa_name_ver
- && n1->store == n2->store
- && n1->offset == n2->offset
- && n1->size == n2->size;
+ return operand_equal_p (n1->exp, n2->exp, OEP_ADDRESS_OF)
+ && n1->size == n2->size;
}
class nontrapping_dom_walker : public dom_walker
{
public:
nontrapping_dom_walker (cdi_direction direction, hash_set<tree> *ps)
- : dom_walker (direction), m_nontrapping (ps), m_seen_ssa_names (128) {}
+ : dom_walker (direction), m_nontrapping (ps), m_seen_refs (128)
+ {}
virtual edge before_dom_children (basic_block);
virtual void after_dom_children (basic_block);
hash_set<tree> *m_nontrapping;
/* The hash table for remembering what we've seen. */
- hash_table<ssa_names_hasher> m_seen_ssa_names;
+ hash_table<refs_hasher> m_seen_refs;
};
/* Called by walk_dominator_tree, when entering the block BB. */
}
/* We see the expression EXP in basic block BB. If it's an interesting
- expression (an MEM_REF through an SSA_NAME) possibly insert the
- expression into the set NONTRAP or the hash table of seen expressions.
- STORE is true if this expression is on the LHS, otherwise it's on
- the RHS. */
+ expression of:
+ 1) MEM_REF
+ 2) ARRAY_REF
+ 3) COMPONENT_REF
+ possibly insert the expression into the set NONTRAP or the hash table
+ of seen expressions. STORE is true if this expression is on the LHS,
+ otherwise it's on the RHS. */
void
nontrapping_dom_walker::add_or_mark_expr (basic_block bb, tree exp, bool store)
{
HOST_WIDE_INT size;
- if (TREE_CODE (exp) == MEM_REF
- && TREE_CODE (TREE_OPERAND (exp, 0)) == SSA_NAME
- && tree_fits_shwi_p (TREE_OPERAND (exp, 1))
+ if ((TREE_CODE (exp) == MEM_REF || TREE_CODE (exp) == ARRAY_REF
+ || TREE_CODE (exp) == COMPONENT_REF)
&& (size = int_size_in_bytes (TREE_TYPE (exp))) > 0)
{
- tree name = TREE_OPERAND (exp, 0);
- struct name_to_bb map;
- name_to_bb **slot;
- struct name_to_bb *n2bb;
+ struct ref_to_bb map;
+ ref_to_bb **slot;
+ struct ref_to_bb *r2bb;
basic_block found_bb = 0;
- /* Try to find the last seen MEM_REF through the same
- SSA_NAME, which can trap. */
- map.ssa_name_ver = SSA_NAME_VERSION (name);
- map.phase = 0;
- map.bb = 0;
- map.store = store;
- map.offset = tree_to_shwi (TREE_OPERAND (exp, 1));
- map.size = size;
+ if (!store)
+ {
+ tree base = get_base_address (exp);
+ /* Only record a LOAD of a local variable without address-taken, as
+ the local stack is always writable. This allows cselim on a STORE
+ with a dominating LOAD. */
+ if (!auto_var_p (base) || TREE_ADDRESSABLE (base))
+ return;
+ }
- slot = m_seen_ssa_names.find_slot (&map, INSERT);
- n2bb = *slot;
- if (n2bb && n2bb->phase >= nt_call_phase)
- found_bb = n2bb->bb;
+ /* Try to find the last seen *_REF, which can trap. */
+ map.exp = exp;
+ map.size = size;
+ slot = m_seen_refs.find_slot (&map, INSERT);
+ r2bb = *slot;
+ if (r2bb && r2bb->phase >= nt_call_phase)
+ found_bb = r2bb->bb;
- /* If we've found a trapping MEM_REF, _and_ it dominates EXP
- (it's in a basic block on the path from us to the dominator root)
+ /* If we've found a trapping *_REF, _and_ it dominates EXP
+ (it's in a basic block on the path from us to the dominator root)
then we can't trap. */
if (found_bb && (((size_t)found_bb->aux) & 1) == 1)
{
m_nontrapping->add (exp);
}
else
- {
+ {
/* EXP might trap, so insert it into the hash table. */
- if (n2bb)
+ if (r2bb)
{
- n2bb->phase = nt_call_phase;
- n2bb->bb = bb;
+ r2bb->phase = nt_call_phase;
+ r2bb->bb = bb;
}
else
{
- n2bb = XNEW (struct name_to_bb);
- n2bb->ssa_name_ver = SSA_NAME_VERSION (name);
- n2bb->phase = nt_call_phase;
- n2bb->bb = bb;
- n2bb->store = store;
- n2bb->offset = map.offset;
- n2bb->size = size;
- *slot = n2bb;
+ r2bb = XNEW (struct ref_to_bb);
+ r2bb->phase = nt_call_phase;
+ r2bb->bb = bb;
+ r2bb->exp = exp;
+ r2bb->size = size;
+ *slot = r2bb;
}
}
}
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