/* Alias analysis for GNU C
- Copyright (C) 1997-2019 Free Software Foundation, Inc.
+ Copyright (C) 1997-2020 Free Software Foundation, Inc.
Contributed by John Carr (jfc@mit.edu).
This file is part of GCC.
&& MEM_ALIAS_SET (mem) != 0);
}
+/* Return true if the ref EARLIER behaves the same as LATER with respect
+ to TBAA for every memory reference that might follow LATER. */
+
+bool
+refs_same_for_tbaa_p (tree earlier, tree later)
+{
+ ao_ref earlier_ref, later_ref;
+ ao_ref_init (&earlier_ref, earlier);
+ ao_ref_init (&later_ref, later);
+ alias_set_type earlier_set = ao_ref_alias_set (&earlier_ref);
+ alias_set_type later_set = ao_ref_alias_set (&later_ref);
+ if (!(earlier_set == later_set
+ || alias_set_subset_of (later_set, earlier_set)))
+ return false;
+ alias_set_type later_base_set = ao_ref_base_alias_set (&later_ref);
+ alias_set_type earlier_base_set = ao_ref_base_alias_set (&earlier_ref);
+ return (earlier_base_set == later_base_set
+ || alias_set_subset_of (later_base_set, earlier_base_set));
+}
+
/* Returns a pointer to the alias set entry for ALIAS_SET, if there is
such an entry, or NULL otherwise. */
return alias_sets_must_conflict_p (set1, set2);
}
\f
+/* Return true if T is an end of the access path which can be used
+ by type based alias oracle. */
+
+bool
+ends_tbaa_access_path_p (const_tree t)
+{
+ switch (TREE_CODE (t))
+ {
+ case COMPONENT_REF:
+ if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
+ return true;
+ /* Permit type-punning when accessing a union, provided the access
+ is directly through the union. For example, this code does not
+ permit taking the address of a union member and then storing
+ through it. Even the type-punning allowed here is a GCC
+ extension, albeit a common and useful one; the C standard says
+ that such accesses have implementation-defined behavior. */
+ else if (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == UNION_TYPE)
+ return true;
+ break;
+
+ case ARRAY_REF:
+ case ARRAY_RANGE_REF:
+ if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))))
+ return true;
+ break;
+
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ break;
+
+ case BIT_FIELD_REF:
+ case VIEW_CONVERT_EXPR:
+ /* Bitfields and casts are never addressable. */
+ return true;
+ break;
+
+ default:
+ gcc_unreachable ();
+ }
+ return false;
+}
+
/* Return the outermost parent of component present in the chain of
component references handled by get_inner_reference in T with the
following property:
while (handled_component_p (t))
{
- switch (TREE_CODE (t))
- {
- case COMPONENT_REF:
- if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
- found = t;
- /* Permit type-punning when accessing a union, provided the access
- is directly through the union. For example, this code does not
- permit taking the address of a union member and then storing
- through it. Even the type-punning allowed here is a GCC
- extension, albeit a common and useful one; the C standard says
- that such accesses have implementation-defined behavior. */
- else if (TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == UNION_TYPE)
- found = t;
- break;
-
- case ARRAY_REF:
- case ARRAY_RANGE_REF:
- if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))))
- found = t;
- break;
-
- case REALPART_EXPR:
- case IMAGPART_EXPR:
- break;
-
- case BIT_FIELD_REF:
- case VIEW_CONVERT_EXPR:
- /* Bitfields and casts are never addressable. */
- found = t;
- break;
-
- default:
- gcc_unreachable ();
- }
+ if (ends_tbaa_access_path_p (t))
+ found = t;
t = TREE_OPERAND (t, 0);
}
alias_set_type set;
/* We cannot give up with -fno-strict-aliasing because we need to build
- proper type representation for possible functions which are build with
+ proper type representations for possible functions which are built with
-fstrict-aliasing. */
/* return 0 if this or its type is an error. */
if (set != -1)
return set;
/* Handle structure type equality for pointer types, arrays and vectors.
- This is easy to do, because the code bellow ignore canonical types on
+ This is easy to do, because the code below ignores canonical types on
these anyway. This is important for LTO, where TYPE_CANONICAL for
- pointers cannot be meaningfuly computed by the frotnend. */
+ pointers cannot be meaningfully computed by the frontend. */
if (canonical_type_used_p (t))
{
/* In LTO we set canonical types for all types where it makes
|| TREE_CODE (p) == VECTOR_TYPE;
p = TREE_TYPE (p))
{
- /* Ada supports recusive pointers. Instead of doing recrusion check
- just give up once the preallocated space of 8 elements is up.
- In this case just punt to void * alias set. */
+ /* Ada supports recursive pointers. Instead of doing recursion
+ check, just give up once the preallocated space of 8 elements
+ is up. In this case just punt to void * alias set. */
if (reference.length () == 8)
{
p = ptr_type_node;
}
p = TYPE_MAIN_VARIANT (p);
- /* In LTO for C++ programs we can turn in complete types to complete
+ /* In LTO for C++ programs we can turn incomplete types to complete
using ODR name lookup. */
if (in_lto_p && TYPE_STRUCTURAL_EQUALITY_P (p) && odr_type_p (p))
{
superset_entry->has_zero_child = 1;
else
{
- subset_entry = get_alias_set_entry (subset);
if (!superset_entry->children)
superset_entry->children
= hash_map<alias_set_hash, int>::create_ggc (64);
+
+ /* Enter the SUBSET itself as a child of the SUPERSET. If it was
+ already there we're done. */
+ if (superset_entry->children->put (subset, 0))
+ return;
+
+ subset_entry = get_alias_set_entry (subset);
/* If there is an entry for the subset, enter all of its children
(if they are not already present) as children of the SUPERSET. */
if (subset_entry)
superset_entry->children->put ((*iter).first, (*iter).second);
}
}
-
- /* Enter the SUBSET itself as a child of the SUPERSET. */
- superset_entry->children->put (subset, 0);
}
}
-/* Record that component types of TYPE, if any, are part of that type for
+/* Record that component types of TYPE, if any, are part of SUPERSET for
aliasing purposes. For record types, we only record component types
for fields that are not marked non-addressable. For array types, we
only record the component type if it is not marked non-aliased. */
void
-record_component_aliases (tree type)
+record_component_aliases (tree type, alias_set_type superset)
{
- alias_set_type superset = get_alias_set (type);
tree field;
if (superset == 0)
== get_alias_set (TREE_TYPE (field)));
}
- record_alias_subset (superset, get_alias_set (t));
+ alias_set_type set = get_alias_set (t);
+ record_alias_subset (superset, set);
+ /* If the field has alias-set zero make sure to still record
+ any componets of it. This makes sure that for
+ struct A {
+ struct B {
+ int i;
+ char c[4];
+ } b;
+ };
+ in C++ even though 'B' has alias-set zero because
+ TYPE_TYPELESS_STORAGE is set, 'A' has the alias-set of
+ 'int' as subset. */
+ if (set == 0)
+ record_component_aliases (t, superset);
}
}
break;
}
}
+/* Record that component types of TYPE, if any, are part of that type for
+ aliasing purposes. For record types, we only record component types
+ for fields that are not marked non-addressable. For array types, we
+ only record the component type if it is not marked non-aliased. */
+
+void
+record_component_aliases (tree type)
+{
+ alias_set_type superset = get_alias_set (type);
+ record_component_aliases (type, superset);
+}
+
+
/* Allocate an alias set for use in storing and reading from the varargs
spill area. */
return find_base_value (XEXP (src, 1));
case AND:
- /* If the second operand is constant set the base
- address to the first operand. */
- if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0)
+ /* Look through aligning ANDs. And AND with zero or one with
+ the LSB set isn't one (see for example PR92462). */
+ if (CONST_INT_P (XEXP (src, 1))
+ && INTVAL (XEXP (src, 1)) != 0
+ && (INTVAL (XEXP (src, 1)) & 1) == 0)
return find_base_value (XEXP (src, 0));
return 0;
new_reg_base_value[regno] = 0;
return;
}
- /* A CLOBBER_HIGH only wipes out the old value if the mode of the old
- value is greater than that of the clobber. */
- else if (GET_CODE (set) == CLOBBER_HIGH)
- {
- if (new_reg_base_value[regno] != 0
- && reg_is_clobbered_by_clobber_high (
- regno, GET_MODE (new_reg_base_value[regno]), XEXP (set, 0)))
- new_reg_base_value[regno] = 0;
- return;
- }
src = SET_SRC (set);
}
if (cselib_sp_based_value_p (val))
return static_reg_base_value[STACK_POINTER_REGNUM];
+ if (visited_vals.length () > (unsigned) param_max_find_base_term_values)
+ return ret;
+
f = val->locs;
/* Reset val->locs to avoid infinite recursion. */
if (f)
}
case AND:
- if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0)
+ /* Look through aligning ANDs. And AND with zero or one with
+ the LSB set isn't one (see for example PR92462). */
+ if (CONST_INT_P (XEXP (x, 1))
+ && INTVAL (XEXP (x, 1)) != 0
+ && (INTVAL (XEXP (x, 1)) & 1) == 0)
return find_base_term (XEXP (x, 0), visited_vals);
return 0;
if (CALL_P (insn))
return true;
memory_modified = false;
- note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem));
+ note_stores (as_a<const rtx_insn *> (insn), memory_modified_1,
+ CONST_CAST_RTX(mem));
return memory_modified;
}
&& find_reg_note (insn, REG_NOALIAS, NULL_RTX))
record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL);
else
- note_stores (PATTERN (insn), record_set, NULL);
+ note_stores (insn, record_set, NULL);
set = single_set (insn);
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