return !modified;
}
-/* Return true if we can prove that OP is a memory reference loading unmodified
- data from an aggregate passed as a parameter and if the aggregate is passed
- by reference, that the alias type of the load corresponds to the type of the
- formal parameter (so that we can rely on this type for TBAA in callers).
+/* Return true if we can prove that OP is a memory reference loading
+ data from an aggregate passed as a parameter.
+
+ The function works in two modes. If GUARANTEED_UNMODIFIED is NULL, it return
+ false if it cannot prove that the value has not been modified before the
+ load in STMT. If GUARANTEED_UNMODIFIED is not NULL, it will return true even
+ if it cannot prove the value has not been modified, in that case it will
+ store false to *GUARANTEED_UNMODIFIED, otherwise it will store true there.
+
INFO and PARMS_AINFO describe parameters of the current function (but the
latter can be NULL), STMT is the load statement. If function returns true,
*INDEX_P, *OFFSET_P and *BY_REF is filled with the parameter index, offset
vec<ipa_param_descriptor> descriptors,
gimple *stmt, tree op, int *index_p,
HOST_WIDE_INT *offset_p, HOST_WIDE_INT *size_p,
- bool *by_ref_p)
+ bool *by_ref_p, bool *guaranteed_unmodified)
{
int index;
HOST_WIDE_INT size, max_size;
*by_ref_p = false;
if (size_p)
*size_p = size;
+ if (guaranteed_unmodified)
+ *guaranteed_unmodified = true;
return true;
}
return false;
index = load_from_unmodified_param (fbi, descriptors, def);
}
- if (index >= 0
- && parm_ref_data_preserved_p (fbi, index, stmt, op))
+ if (index >= 0)
{
+ bool data_preserved = parm_ref_data_preserved_p (fbi, index, stmt, op);
+ if (!data_preserved && !guaranteed_unmodified)
+ return false;
+
*index_p = index;
*by_ref_p = true;
if (size_p)
*size_p = size;
+ if (guaranteed_unmodified)
+ *guaranteed_unmodified = data_preserved;
return true;
}
return false;
cs->indirect_info->param_index = param_index;
cs->indirect_info->agg_contents = 0;
cs->indirect_info->member_ptr = 0;
+ cs->indirect_info->guaranteed_unmodified = 0;
return cs;
}
int index;
gimple *def = SSA_NAME_DEF_STMT (target);
+ bool guaranteed_unmodified;
if (gimple_assign_single_p (def)
&& ipa_load_from_parm_agg (fbi, info->descriptors, def,
gimple_assign_rhs1 (def), &index, &offset,
- NULL, &by_ref))
+ NULL, &by_ref, &guaranteed_unmodified))
{
struct cgraph_edge *cs = ipa_note_param_call (fbi->node, index, call);
cs->indirect_info->offset = offset;
cs->indirect_info->agg_contents = 1;
cs->indirect_info->by_ref = by_ref;
+ cs->indirect_info->guaranteed_unmodified = guaranteed_unmodified;
return;
}
cs->indirect_info->offset = offset;
cs->indirect_info->agg_contents = 1;
cs->indirect_info->member_ptr = 1;
+ cs->indirect_info->guaranteed_unmodified = 1;
}
return;
return ie;
}
-/* Retrieve value from aggregate jump function AGG for the given OFFSET or
- return NULL if there is not any. BY_REF specifies whether the value has to
- be passed by reference or by value. */
+/* Attempt to locate an interprocedural constant at a given REQ_OFFSET in
+ CONSTRUCTOR and return it. Return NULL if the search fails for some
+ reason. */
+
+static tree
+find_constructor_constant_at_offset (tree constructor, HOST_WIDE_INT req_offset)
+{
+ tree type = TREE_TYPE (constructor);
+ if (TREE_CODE (type) != ARRAY_TYPE
+ && TREE_CODE (type) != RECORD_TYPE)
+ return NULL;
+
+ unsigned ix;
+ tree index, val;
+ FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (constructor), ix, index, val)
+ {
+ HOST_WIDE_INT elt_offset;
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ offset_int off;
+ tree unit_size = TYPE_SIZE_UNIT (TREE_TYPE (type));
+ gcc_assert (TREE_CODE (unit_size) == INTEGER_CST);
+
+ if (index)
+ {
+ off = wi::to_offset (index);
+ if (TYPE_DOMAIN (type) && TYPE_MIN_VALUE (TYPE_DOMAIN (type)))
+ {
+ tree low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (type));
+ gcc_assert (TREE_CODE (unit_size) == INTEGER_CST);
+ off = wi::sext (off - wi::to_offset (low_bound),
+ TYPE_PRECISION (TREE_TYPE (index)));
+ }
+ off *= wi::to_offset (unit_size);
+ }
+ else
+ off = wi::to_offset (unit_size) * ix;
+
+ off = wi::lshift (off, LOG2_BITS_PER_UNIT);
+ if (!wi::fits_shwi_p (off) || wi::neg_p (off))
+ continue;
+ elt_offset = off.to_shwi ();
+ }
+ else if (TREE_CODE (type) == RECORD_TYPE)
+ {
+ gcc_checking_assert (index && TREE_CODE (index) == FIELD_DECL);
+ if (DECL_BIT_FIELD (index))
+ continue;
+ elt_offset = int_bit_position (index);
+ }
+ else
+ gcc_unreachable ();
+
+ if (elt_offset > req_offset)
+ return NULL;
+
+ if (TREE_CODE (val) == CONSTRUCTOR)
+ return find_constructor_constant_at_offset (val,
+ req_offset - elt_offset);
+
+ if (elt_offset == req_offset
+ && is_gimple_reg_type (TREE_TYPE (val))
+ && is_gimple_ip_invariant (val))
+ return val;
+ }
+ return NULL;
+}
+
+/* Check whether SCALAR could be used to look up an aggregate interprocedural
+ invariant from a static constructor and if so, return it. Otherwise return
+ NULL. */
+
+static tree
+ipa_find_agg_cst_from_init (tree scalar, HOST_WIDE_INT offset, bool by_ref)
+{
+ if (by_ref)
+ {
+ if (TREE_CODE (scalar) != ADDR_EXPR)
+ return NULL;
+ scalar = TREE_OPERAND (scalar, 0);
+ }
+
+ if (TREE_CODE (scalar) != VAR_DECL
+ || !is_global_var (scalar)
+ || !TREE_READONLY (scalar)
+ || !DECL_INITIAL (scalar)
+ || TREE_CODE (DECL_INITIAL (scalar)) != CONSTRUCTOR)
+ return NULL;
+
+ return find_constructor_constant_at_offset (DECL_INITIAL (scalar), offset);
+}
+
+/* Retrieve value from aggregate jump function AGG or static initializer of
+ SCALAR (which can be NULL) for the given OFFSET or return NULL if there is
+ none. BY_REF specifies whether the value has to be passed by reference or
+ by value. If FROM_GLOBAL_CONSTANT is non-NULL, then the boolean it points
+ to is set to true if the value comes from an initializer of a constant. */
tree
-ipa_find_agg_cst_for_param (struct ipa_agg_jump_function *agg,
- HOST_WIDE_INT offset, bool by_ref)
+ipa_find_agg_cst_for_param (struct ipa_agg_jump_function *agg, tree scalar,
+ HOST_WIDE_INT offset, bool by_ref,
+ bool *from_global_constant)
{
struct ipa_agg_jf_item *item;
int i;
- if (by_ref != agg->by_ref)
+ if (scalar)
+ {
+ tree res = ipa_find_agg_cst_from_init (scalar, offset, by_ref);
+ if (res)
+ {
+ if (from_global_constant)
+ *from_global_constant = true;
+ return res;
+ }
+ }
+
+ if (!agg
+ || by_ref != agg->by_ref)
return NULL;
FOR_EACH_VEC_SAFE_ELT (agg->items, i, item)
/* Currently we do not have clobber values, return NULL for them once
we do. */
gcc_checking_assert (is_gimple_ip_invariant (item->value));
+ if (from_global_constant)
+ *from_global_constant = false;
return item->value;
}
return NULL;
struct cgraph_edge *cs;
tree target;
bool agg_contents = ie->indirect_info->agg_contents;
-
- if (ie->indirect_info->agg_contents)
- target = ipa_find_agg_cst_for_param (&jfunc->agg,
- ie->indirect_info->offset,
- ie->indirect_info->by_ref);
+ tree scalar = ipa_value_from_jfunc (new_root_info, jfunc);
+ if (agg_contents)
+ {
+ bool from_global_constant;
+ target = ipa_find_agg_cst_for_param (&jfunc->agg, scalar,
+ ie->indirect_info->offset,
+ ie->indirect_info->by_ref,
+ &from_global_constant);
+ if (target
+ && !from_global_constant
+ && !ie->indirect_info->guaranteed_unmodified)
+ return NULL;
+ }
else
- target = ipa_value_from_jfunc (new_root_info, jfunc);
+ target = scalar;
if (!target)
return NULL;
cs = ipa_make_edge_direct_to_target (ie, target);
{
tree vtable;
unsigned HOST_WIDE_INT offset;
- tree t = ipa_find_agg_cst_for_param (&jfunc->agg,
+ tree scalar = (jfunc->type == IPA_JF_CONST) ? ipa_get_jf_constant (jfunc)
+ : NULL;
+ tree t = ipa_find_agg_cst_for_param (&jfunc->agg, scalar,
ie->indirect_info->offset,
true);
if (t && vtable_pointer_value_to_vtable (t, &vtable, &offset))
bp_pack_value (&bp, ii->agg_contents, 1);
bp_pack_value (&bp, ii->member_ptr, 1);
bp_pack_value (&bp, ii->by_ref, 1);
+ bp_pack_value (&bp, ii->guaranteed_unmodified, 1);
bp_pack_value (&bp, ii->vptr_changed, 1);
streamer_write_bitpack (&bp);
if (ii->agg_contents || ii->polymorphic)
ii->agg_contents = bp_unpack_value (&bp, 1);
ii->member_ptr = bp_unpack_value (&bp, 1);
ii->by_ref = bp_unpack_value (&bp, 1);
+ ii->guaranteed_unmodified = bp_unpack_value (&bp, 1);
ii->vptr_changed = bp_unpack_value (&bp, 1);
if (ii->agg_contents || ii->polymorphic)
ii->offset = (HOST_WIDE_INT) streamer_read_hwi (ib);
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