/* Alias analysis for GNU C
- Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
+ Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
Free Software Foundation, Inc.
Contributed by John Carr (jfc@mit.edu).
static int nonlocal_set_p_1 (rtx *, void *);
static int nonlocal_set_p (rtx);
static void memory_modified_1 (rtx, rtx, void *);
+static void record_alias_subset (HOST_WIDE_INT, HOST_WIDE_INT);
/* Set up all info needed to perform alias analysis on memory references. */
static inline int
mems_in_disjoint_alias_sets_p (rtx mem1, rtx mem2)
{
-#ifdef ENABLE_CHECKING
/* Perform a basic sanity check. Namely, that there are no alias sets
if we're not using strict aliasing. This helps to catch bugs
whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or
gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to
use alias sets to indicate that spilled registers cannot alias each
other, we might need to remove this check. */
- if (! flag_strict_aliasing
- && (MEM_ALIAS_SET (mem1) != 0 || MEM_ALIAS_SET (mem2) != 0))
- abort ();
-#endif
+ gcc_assert (flag_strict_aliasing
+ || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2)));
return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2));
}
}
\f
-/* Return 1 if TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE and has
- has any readonly fields. If any of the fields have types that
- contain readonly fields, return true as well. */
-
-int
-readonly_fields_p (tree type)
-{
- tree field;
-
- if (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
- && TREE_CODE (type) != QUAL_UNION_TYPE)
- return 0;
-
- for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field))
- if (TREE_CODE (field) == FIELD_DECL
- && (TREE_READONLY (field)
- || readonly_fields_p (TREE_TYPE (field))))
- return 1;
-
- return 0;
-}
-\f
/* Return 1 if any MEM object of type T1 will always conflict (using the
dependency routines in this file) with any MEM object of type T2.
This is used when allocating temporary storage. If T1 and/or T2 are
if (t1 == 0 && t2 == 0)
return 0;
- /* If one or the other has readonly fields or is readonly,
- then they may not conflict. */
- if ((t1 != 0 && readonly_fields_p (t1))
- || (t2 != 0 && readonly_fields_p (t2))
- || (t1 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t1))
- || (t2 != 0 && lang_hooks.honor_readonly && TYPE_READONLY (t2)))
- return 0;
-
/* If they are the same type, they must conflict. */
if (t1 == t2
/* Likewise if both are volatile. */
static tree
find_base_decl (tree t)
{
- tree d0, d1, d2;
+ tree d0, d1;
if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t)))
return 0;
/* If this is a declaration, return it. */
- if (TREE_CODE_CLASS (TREE_CODE (t)) == 'd')
+ if (DECL_P (t))
return t;
/* Handle general expressions. It would be nice to deal with
same, then `a->f' and `b->f' are also the same. */
switch (TREE_CODE_CLASS (TREE_CODE (t)))
{
- case '1':
+ case tcc_unary:
return find_base_decl (TREE_OPERAND (t, 0));
- case '2':
+ case tcc_binary:
/* Return 0 if found in neither or both are the same. */
d0 = find_base_decl (TREE_OPERAND (t, 0));
d1 = find_base_decl (TREE_OPERAND (t, 1));
else
return 0;
- case '3':
- d0 = find_base_decl (TREE_OPERAND (t, 0));
- d1 = find_base_decl (TREE_OPERAND (t, 1));
- d2 = find_base_decl (TREE_OPERAND (t, 2));
-
- /* Set any nonzero values from the last, then from the first. */
- if (d1 == 0) d1 = d2;
- if (d0 == 0) d0 = d1;
- if (d1 == 0) d1 = d0;
- if (d2 == 0) d2 = d1;
-
- /* At this point all are nonzero or all are zero. If all three are the
- same, return it. Otherwise, return zero. */
- return (d0 == d1 && d1 == d2) ? d0 : 0;
-
default:
return 0;
}
}
-/* Return 1 if all the nested component references handled by
- get_inner_reference in T are such that we can address the object in T. */
+/* Return true if all nested component references handled by
+ get_inner_reference in T are such that we should use the alias set
+ provided by the object at the heart of T.
-int
-can_address_p (tree t)
+ This is true for non-addressable components (which don't have their
+ own alias set), as well as components of objects in alias set zero.
+ This later point is a special case wherein we wish to override the
+ alias set used by the component, but we don't have per-FIELD_DECL
+ assignable alias sets. */
+
+bool
+component_uses_parent_alias_set (tree t)
{
- /* If we're at the end, it is vacuously addressable. */
- if (! handled_component_p (t))
- return 1;
+ while (1)
+ {
+ /* If we're at the end, it vacuously uses its own alias set. */
+ if (!handled_component_p (t))
+ return false;
- /* Bitfields are never addressable. */
- else if (TREE_CODE (t) == BIT_FIELD_REF)
- return 0;
+ switch (TREE_CODE (t))
+ {
+ case COMPONENT_REF:
+ if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
+ return true;
+ break;
- /* Fields are addressable unless they are marked as nonaddressable or
- the containing type has alias set 0. */
- else if (TREE_CODE (t) == COMPONENT_REF
- && ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))
- && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0
- && can_address_p (TREE_OPERAND (t, 0)))
- return 1;
+ case ARRAY_REF:
+ case ARRAY_RANGE_REF:
+ if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))))
+ return true;
+ break;
- /* Likewise for arrays. */
- else if ((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
- && ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))
- && get_alias_set (TREE_TYPE (TREE_OPERAND (t, 0))) != 0
- && can_address_p (TREE_OPERAND (t, 0)))
- return 1;
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ break;
- return 0;
+ default:
+ /* Bitfields and casts are never addressable. */
+ return true;
+ }
+
+ t = TREE_OPERAND (t, 0);
+ if (get_alias_set (TREE_TYPE (t)) == 0)
+ return true;
+ }
}
/* Return the alias set for T, which may be either a type or an
}
/* Check for accesses through restrict-qualified pointers. */
- if (TREE_CODE (inner) == INDIRECT_REF)
+ if (INDIRECT_REF_P (inner))
{
tree decl = find_base_decl (TREE_OPERAND (inner, 0));
type, then we would believe that other subsets
of the pointed-to type (such as fields of that
type) do not conflict with the type pointed to
- by the restricted pointer. */
+ by the restricted pointer. */
DECL_POINTER_ALIAS_SET (decl)
= pointed_to_alias_set;
else
/* Otherwise, pick up the outermost object that we could have a pointer
to, processing conversions as above. */
- while (handled_component_p (t) && ! can_address_p (t))
+ while (component_uses_parent_alias_set (t))
{
t = TREE_OPERAND (t, 0);
STRIP_NOPS (t);
It is illegal for SUPERSET to be zero; everything is implicitly a
subset of alias set zero. */
-void
+static void
record_alias_subset (HOST_WIDE_INT superset, HOST_WIDE_INT subset)
{
alias_set_entry superset_entry;
if (superset == subset)
return;
- if (superset == 0)
- abort ();
+ gcc_assert (superset);
superset_entry = get_alias_set_entry (superset);
if (superset_entry == 0)
regno = REGNO (dest);
- if (regno >= VARRAY_SIZE (reg_base_value))
- abort ();
+ gcc_assert (regno < VARRAY_SIZE (reg_base_value));
/* If this spans multiple hard registers, then we must indicate that every
register has an unusable value. */
contain anything but integers and other rtx's,
except for within LABEL_REFs and SYMBOL_REFs. */
default:
- abort ();
+ gcc_unreachable ();
}
}
return 1;
where SIZE is the size in bytes of the memory reference. If ADDR
is not modified by the memory reference then ADDR is returned. */
-rtx
+static rtx
addr_side_effect_eval (rtx addr, int size, int n_refs)
{
int offset = 0;
aliases_everything_p (rtx mem)
{
if (GET_CODE (XEXP (mem, 0)) == AND)
- /* If the address is an AND, its very hard to know at what it is
+ /* If the address is an AND, it's very hard to know at what it is
actually pointing. */
return 1;
moffsetx = adjust_offset_for_component_ref (exprx, moffsetx);
exprx = t;
}
- else if (TREE_CODE (exprx) == INDIRECT_REF)
+ else if (INDIRECT_REF_P (exprx))
{
exprx = TREE_OPERAND (exprx, 0);
if (flag_argument_noalias < 2
moffsety = adjust_offset_for_component_ref (expry, moffsety);
expry = t;
}
- else if (TREE_CODE (expry) == INDIRECT_REF)
+ else if (INDIRECT_REF_P (expry))
{
expry = TREE_OPERAND (expry, 0);
if (flag_argument_noalias < 2
/* Read-only memory is by definition never modified, and therefore can't
conflict with anything. We don't expect to find read-only set on MEM,
- but stupid user tricks can produce them, so don't abort. */
+ but stupid user tricks can produce them, so don't die. */
if (MEM_READONLY_P (x))
return 0;
/* Read-only memory is by definition never modified, and therefore can't
conflict with anything. We don't expect to find read-only set on MEM,
- but stupid user tricks can produce them, so don't abort. */
+ but stupid user tricks can produce them, so don't die. */
if (MEM_READONLY_P (x))
return 0;
/* Return true when INSN possibly modify memory contents of MEM
- (ie address can be modified). */
+ (i.e. address can be modified). */
bool
memory_modified_in_insn_p (rtx mem, rtx insn)
{
new_reg_base_value = xmalloc (maxreg * sizeof (rtx));
reg_seen = xmalloc (maxreg);
- if (! reload_completed && flag_old_unroll_loops)
- {
- alias_invariant = ggc_calloc (maxreg, sizeof (rtx));
- alias_invariant_size = maxreg;
- }
/* The basic idea is that each pass through this loop will use the
"constant" information from the previous pass to propagate alias
}
/* Now propagate values from new_reg_base_value to reg_base_value. */
- if (maxreg != (unsigned int) max_reg_num())
- abort ();
+ gcc_assert (maxreg == (unsigned int) max_reg_num());
+
for (ui = 0; ui < maxreg; ui++)
{
if (new_reg_base_value[ui]
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