mirror of
git://gcc.gnu.org/git/gcc.git
synced 2024-12-24 08:49:18 +08:00
69ef87e2bc
2002-02-19 Aldy Hernandez <aldyh@redhat.com>
* config/i386/i386.md ("mmx_uavgv8qi3"): Use const_vector.
("mmx_uavgv4hi3"): Same.
("pmulhrwv4hi3"): Same.
* tree-inline.c (walk_tree): Handle vectors.
* c-common.c (constant_expression_warning): Handle vectors.
(overflow_warning): Same.
* sched-deps.c (sched_analyze_2): Handle vectors.
* rtlanal.c (rtx_unstable_p): Handle vectors.
(rtx_varies_p): Same.
(count_occurrences): Same.
(regs_set_between_p): Same.
(modified_between_p): Same.
(modified_in_p): Same.
(volatile_insn_p): Same.
(volatile_refs_p): Same.
(side_effects_p): Same.
(may_trap_p): Same.
(inequality_comparisons_p): Same.
(replace_regs): Same.
(computed_jump_p_1): Same.
* rtl.c (DEF_MACHMODE): Change all definitions to accept 8th
argument.
(inner_mode_array): New.
(copy_rtx): Handle vectors.
(copy_most_rtx): Same.
(rtx_equal_p): Same.
(get_mode_alignment): Adjust for vectors.
* resource.c (mark_referenced_resources): Handle vectors.
(mark_set_resources): Same.
* reload1.c (eliminate_regs): Handle vectors.
(elimination_effects): Same.
(scan_paradoxical_subregs): Same.
* reload.c (subst_reg_equivs): Handle vectors.
* regrename.c (scan_rtx): Handle vectors.
* regclass.c (reg_scan_mark_refs): Handle vectors.
* recog.c (find_single_use_1): Handle vectors.
* local-alloc.c (equiv_init_varies_p): Handle vectors.
(contains_replace_regs): Same.
(memref_referenced_p): Same.
* integrate.c (copy_rtx_and_substitute): Handle vectors.
(subst_constants): Same.
* genattrtab.c (attr_copy_rtx): Handle vectors.
(encode_units_mask): Same.
(clear_struct_flag): Same.
(count_sub_rtxs): Same.
* gcse.c (want_to_gcse_p): Handle vectors.
(oprs_unchanged_p): Same.
(hash_expr_1): Same.
(oprs_not_set_p): Same.
(expr_killed_p): Same.
(compute_transp): Same.
(store_ops_ok): Same.
* function.c (purge_addressof_1): Do not allow paradoxical subregs
of vectors.
(fixup_var_refs_1): Same.
(instantiate_virtual_regs_1): Same.
* fold-const.c (operand_equal_p): Handle vectors.
(fold): Same.
(rtl_expr_nonnegative_p): Same.
* flow.c (mark_used_regs): Handle vectors.
* df.c (df_uses_record): Handle vectors.
* cselib.c (cselib_subst_to_values): Handle vectors.
(cselib_mem_conflict_p): Same.
(hash_rtx): Same.
* cse.c (canon_reg): Handle vectors.
(fold_rt): Same.
(cse_process_notes): Same.
(count_reg_usage): Same.
(canon_hash): Same.
* alias.c (nonlocal_mentioned_p): Add case for CONST_VECTOR.
* combine.c (mark_used_regs_combine): Add case for CONST_VECTOR.
* emit-rtl.c (init_emit_once): Generate const0_rtx for vectors.
(gen_rtx): Handle CONST_VECTOR.
(gen_const_vector_0): New.
(copy_rtx_if_shared): CONST_VECTORs can be shared.
(reset_used_flags): Same.
(copy_insn_1): Same.
(initializer_constant_valid_p): Handle VECTOR_CST.
* doc/c-tree.texi (Expression trees): Document VECTOR_CST.
* doc/rtl.texi (Constants): Document const_vector.
(CONST0_RTX): Update for vectors.
(RTL sharing): Same.
* print-tree.c (print_node): Add case for VECTOR_CST.
* tree.h (TREE_VECTOR_CST_ELTS): New.
(struct tree_vector): New.
(union tree_node): Add vector node.
(build_vector): Add prototype.
* tree.def (VECTOR_CST): New.
* tree.c (build_vector): New.
* expmed.c (make_tree): Handle CONST_VECTOR.
* rtl.h (CONSTANT_P): CONST_VECTORs are constants too.
(CONST_VECTOR_ELT): New.
(CONST_VECTOR_NUNITS): New.
* machmode.h (GET_MODE_INNER): New.
(DEF_MACHMODE): Accept 8th arg.
* machmode.def: Add 8th argument for vector inner mode.
Add inner vector modes for vectors.
* rtl.def (VEC_CONST): Remove.
(CONST_VECTOR): New.
* expr.c (clear_storage): Allow vectors.
(is_zeros_p): Handle VECTOR_CST.
* varasm.c (output_constant_pool): Handle vectors.
(rtx_const): Add veclo and vechi fields.
(kind): Add RTX_VECTOR.
(decode_rtx_const): Add case for vector.
* config/rs6000/rs6000-protos.h: Add zero_constant.
* config/rs6000/rs6000.c (rs6000_emit_move): Handle vector
constants. Force easy vector constants into memory.
(easy_vector_constant): New.
(emit_easy_vector_constant): New.
(rs6000_legitimize_reload_address): Do not generate bad reloads on
darwin.
* config/rs6000/rs6000.md ("altivec_lvx"): Reflect what
instruction does.
("altivec_lvxl"): Same.
(altivec_lvebx): Same.
(altivec_lvehx): Same.
(altivec_lvewx): Same.
("*movv4si_const0"): New.
("*movv4sf_const0"): New.
("*movv8hi_const0"): New.
("*movv16qi_const0"): New.
From-SVN: r49853
2677 lines
77 KiB
C
2677 lines
77 KiB
C
/* Alias analysis for GNU C
|
||
Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
|
||
Contributed by John Carr (jfc@mit.edu).
|
||
|
||
This file is part of GCC.
|
||
|
||
GCC is free software; you can redistribute it and/or modify it under
|
||
the terms of the GNU General Public License as published by the Free
|
||
Software Foundation; either version 2, or (at your option) any later
|
||
version.
|
||
|
||
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
|
||
WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
||
for more details.
|
||
|
||
You should have received a copy of the GNU General Public License
|
||
along with GCC; see the file COPYING. If not, write to the Free
|
||
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
|
||
02111-1307, USA. */
|
||
|
||
#include "config.h"
|
||
#include "system.h"
|
||
#include "rtl.h"
|
||
#include "tree.h"
|
||
#include "tm_p.h"
|
||
#include "function.h"
|
||
#include "expr.h"
|
||
#include "regs.h"
|
||
#include "hard-reg-set.h"
|
||
#include "basic-block.h"
|
||
#include "flags.h"
|
||
#include "output.h"
|
||
#include "toplev.h"
|
||
#include "cselib.h"
|
||
#include "splay-tree.h"
|
||
#include "ggc.h"
|
||
#include "langhooks.h"
|
||
|
||
/* The alias sets assigned to MEMs assist the back-end in determining
|
||
which MEMs can alias which other MEMs. In general, two MEMs in
|
||
different alias sets cannot alias each other, with one important
|
||
exception. Consider something like:
|
||
|
||
struct S {int i; double d; };
|
||
|
||
a store to an `S' can alias something of either type `int' or type
|
||
`double'. (However, a store to an `int' cannot alias a `double'
|
||
and vice versa.) We indicate this via a tree structure that looks
|
||
like:
|
||
struct S
|
||
/ \
|
||
/ \
|
||
|/_ _\|
|
||
int double
|
||
|
||
(The arrows are directed and point downwards.)
|
||
In this situation we say the alias set for `struct S' is the
|
||
`superset' and that those for `int' and `double' are `subsets'.
|
||
|
||
To see whether two alias sets can point to the same memory, we must
|
||
see if either alias set is a subset of the other. We need not trace
|
||
past immediate descendents, however, since we propagate all
|
||
grandchildren up one level.
|
||
|
||
Alias set zero is implicitly a superset of all other alias sets.
|
||
However, this is no actual entry for alias set zero. It is an
|
||
error to attempt to explicitly construct a subset of zero. */
|
||
|
||
typedef struct alias_set_entry
|
||
{
|
||
/* The alias set number, as stored in MEM_ALIAS_SET. */
|
||
HOST_WIDE_INT alias_set;
|
||
|
||
/* The children of the alias set. These are not just the immediate
|
||
children, but, in fact, all descendents. So, if we have:
|
||
|
||
struct T { struct S s; float f; }
|
||
|
||
continuing our example above, the children here will be all of
|
||
`int', `double', `float', and `struct S'. */
|
||
splay_tree children;
|
||
|
||
/* Nonzero if would have a child of zero: this effectively makes this
|
||
alias set the same as alias set zero. */
|
||
int has_zero_child;
|
||
} *alias_set_entry;
|
||
|
||
static int rtx_equal_for_memref_p PARAMS ((rtx, rtx));
|
||
static rtx find_symbolic_term PARAMS ((rtx));
|
||
rtx get_addr PARAMS ((rtx));
|
||
static int memrefs_conflict_p PARAMS ((int, rtx, int, rtx,
|
||
HOST_WIDE_INT));
|
||
static void record_set PARAMS ((rtx, rtx, void *));
|
||
static rtx find_base_term PARAMS ((rtx));
|
||
static int base_alias_check PARAMS ((rtx, rtx, enum machine_mode,
|
||
enum machine_mode));
|
||
static rtx find_base_value PARAMS ((rtx));
|
||
static int mems_in_disjoint_alias_sets_p PARAMS ((rtx, rtx));
|
||
static int insert_subset_children PARAMS ((splay_tree_node, void*));
|
||
static tree find_base_decl PARAMS ((tree));
|
||
static alias_set_entry get_alias_set_entry PARAMS ((HOST_WIDE_INT));
|
||
static rtx fixed_scalar_and_varying_struct_p PARAMS ((rtx, rtx, rtx, rtx,
|
||
int (*) (rtx, int)));
|
||
static int aliases_everything_p PARAMS ((rtx));
|
||
static bool nonoverlapping_component_refs_p PARAMS ((tree, tree));
|
||
static tree decl_for_component_ref PARAMS ((tree));
|
||
static rtx adjust_offset_for_component_ref PARAMS ((tree, rtx));
|
||
static int nonoverlapping_memrefs_p PARAMS ((rtx, rtx));
|
||
static int write_dependence_p PARAMS ((rtx, rtx, int));
|
||
static int nonlocal_mentioned_p PARAMS ((rtx));
|
||
|
||
/* Set up all info needed to perform alias analysis on memory references. */
|
||
|
||
/* Returns the size in bytes of the mode of X. */
|
||
#define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X)))
|
||
|
||
/* Returns nonzero if MEM1 and MEM2 do not alias because they are in
|
||
different alias sets. We ignore alias sets in functions making use
|
||
of variable arguments because the va_arg macros on some systems are
|
||
not legal ANSI C. */
|
||
#define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \
|
||
mems_in_disjoint_alias_sets_p (MEM1, MEM2)
|
||
|
||
/* Cap the number of passes we make over the insns propagating alias
|
||
information through set chains. 10 is a completely arbitrary choice. */
|
||
#define MAX_ALIAS_LOOP_PASSES 10
|
||
|
||
/* reg_base_value[N] gives an address to which register N is related.
|
||
If all sets after the first add or subtract to the current value
|
||
or otherwise modify it so it does not point to a different top level
|
||
object, reg_base_value[N] is equal to the address part of the source
|
||
of the first set.
|
||
|
||
A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS
|
||
expressions represent certain special values: function arguments and
|
||
the stack, frame, and argument pointers.
|
||
|
||
The contents of an ADDRESS is not normally used, the mode of the
|
||
ADDRESS determines whether the ADDRESS is a function argument or some
|
||
other special value. Pointer equality, not rtx_equal_p, determines whether
|
||
two ADDRESS expressions refer to the same base address.
|
||
|
||
The only use of the contents of an ADDRESS is for determining if the
|
||
current function performs nonlocal memory memory references for the
|
||
purposes of marking the function as a constant function. */
|
||
|
||
static rtx *reg_base_value;
|
||
static rtx *new_reg_base_value;
|
||
static unsigned int reg_base_value_size; /* size of reg_base_value array */
|
||
|
||
#define REG_BASE_VALUE(X) \
|
||
(REGNO (X) < reg_base_value_size \
|
||
? reg_base_value[REGNO (X)] : 0)
|
||
|
||
/* Vector of known invariant relationships between registers. Set in
|
||
loop unrolling. Indexed by register number, if nonzero the value
|
||
is an expression describing this register in terms of another.
|
||
|
||
The length of this array is REG_BASE_VALUE_SIZE.
|
||
|
||
Because this array contains only pseudo registers it has no effect
|
||
after reload. */
|
||
static rtx *alias_invariant;
|
||
|
||
/* Vector indexed by N giving the initial (unchanging) value known for
|
||
pseudo-register N. This array is initialized in
|
||
init_alias_analysis, and does not change until end_alias_analysis
|
||
is called. */
|
||
rtx *reg_known_value;
|
||
|
||
/* Indicates number of valid entries in reg_known_value. */
|
||
static unsigned int reg_known_value_size;
|
||
|
||
/* Vector recording for each reg_known_value whether it is due to a
|
||
REG_EQUIV note. Future passes (viz., reload) may replace the
|
||
pseudo with the equivalent expression and so we account for the
|
||
dependences that would be introduced if that happens.
|
||
|
||
The REG_EQUIV notes created in assign_parms may mention the arg
|
||
pointer, and there are explicit insns in the RTL that modify the
|
||
arg pointer. Thus we must ensure that such insns don't get
|
||
scheduled across each other because that would invalidate the
|
||
REG_EQUIV notes. One could argue that the REG_EQUIV notes are
|
||
wrong, but solving the problem in the scheduler will likely give
|
||
better code, so we do it here. */
|
||
char *reg_known_equiv_p;
|
||
|
||
/* True when scanning insns from the start of the rtl to the
|
||
NOTE_INSN_FUNCTION_BEG note. */
|
||
static int copying_arguments;
|
||
|
||
/* The splay-tree used to store the various alias set entries. */
|
||
static splay_tree alias_sets;
|
||
|
||
/* Returns a pointer to the alias set entry for ALIAS_SET, if there is
|
||
such an entry, or NULL otherwise. */
|
||
|
||
static alias_set_entry
|
||
get_alias_set_entry (alias_set)
|
||
HOST_WIDE_INT alias_set;
|
||
{
|
||
splay_tree_node sn
|
||
= splay_tree_lookup (alias_sets, (splay_tree_key) alias_set);
|
||
|
||
return sn != 0 ? ((alias_set_entry) sn->value) : 0;
|
||
}
|
||
|
||
/* Returns nonzero if the alias sets for MEM1 and MEM2 are such that
|
||
the two MEMs cannot alias each other. */
|
||
|
||
static int
|
||
mems_in_disjoint_alias_sets_p (mem1, mem2)
|
||
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
|
||
where a MEM is allocated in some way other than by the use of
|
||
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
|
||
|
||
return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2));
|
||
}
|
||
|
||
/* Insert the NODE into the splay tree given by DATA. Used by
|
||
record_alias_subset via splay_tree_foreach. */
|
||
|
||
static int
|
||
insert_subset_children (node, data)
|
||
splay_tree_node node;
|
||
void *data;
|
||
{
|
||
splay_tree_insert ((splay_tree) data, node->key, node->value);
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return 1 if the two specified alias sets may conflict. */
|
||
|
||
int
|
||
alias_sets_conflict_p (set1, set2)
|
||
HOST_WIDE_INT set1, set2;
|
||
{
|
||
alias_set_entry ase;
|
||
|
||
/* If have no alias set information for one of the operands, we have
|
||
to assume it can alias anything. */
|
||
if (set1 == 0 || set2 == 0
|
||
/* If the two alias sets are the same, they may alias. */
|
||
|| set1 == set2)
|
||
return 1;
|
||
|
||
/* See if the first alias set is a subset of the second. */
|
||
ase = get_alias_set_entry (set1);
|
||
if (ase != 0
|
||
&& (ase->has_zero_child
|
||
|| splay_tree_lookup (ase->children,
|
||
(splay_tree_key) set2)))
|
||
return 1;
|
||
|
||
/* Now do the same, but with the alias sets reversed. */
|
||
ase = get_alias_set_entry (set2);
|
||
if (ase != 0
|
||
&& (ase->has_zero_child
|
||
|| splay_tree_lookup (ase->children,
|
||
(splay_tree_key) set1)))
|
||
return 1;
|
||
|
||
/* The two alias sets are distinct and neither one is the
|
||
child of the other. Therefore, they cannot alias. */
|
||
return 0;
|
||
}
|
||
|
||
/* 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 (type)
|
||
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;
|
||
}
|
||
|
||
/* 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
|
||
NULL_TREE, it means we know nothing about the storage. */
|
||
|
||
int
|
||
objects_must_conflict_p (t1, t2)
|
||
tree t1, t2;
|
||
{
|
||
/* If neither has a type specified, we don't know if they'll conflict
|
||
because we may be using them to store objects of various types, for
|
||
example the argument and local variables areas of inlined functions. */
|
||
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 && TYPE_READONLY (t1))
|
||
|| (t2 != 0 && TYPE_READONLY (t2)))
|
||
return 0;
|
||
|
||
/* If they are the same type, they must conflict. */
|
||
if (t1 == t2
|
||
/* Likewise if both are volatile. */
|
||
|| (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2)))
|
||
return 1;
|
||
|
||
/* If one is aggregate and the other is scalar then they may not
|
||
conflict. */
|
||
if ((t1 != 0 && AGGREGATE_TYPE_P (t1))
|
||
!= (t2 != 0 && AGGREGATE_TYPE_P (t2)))
|
||
return 0;
|
||
|
||
/* Otherwise they conflict only if the alias sets conflict. */
|
||
return alias_sets_conflict_p (t1 ? get_alias_set (t1) : 0,
|
||
t2 ? get_alias_set (t2) : 0);
|
||
}
|
||
|
||
/* T is an expression with pointer type. Find the DECL on which this
|
||
expression is based. (For example, in `a[i]' this would be `a'.)
|
||
If there is no such DECL, or a unique decl cannot be determined,
|
||
NULL_TREE is returned. */
|
||
|
||
static tree
|
||
find_base_decl (t)
|
||
tree t;
|
||
{
|
||
tree d0, d1, d2;
|
||
|
||
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')
|
||
return t;
|
||
|
||
/* Handle general expressions. It would be nice to deal with
|
||
COMPONENT_REFs here. If we could tell that `a' and `b' were the
|
||
same, then `a->f' and `b->f' are also the same. */
|
||
switch (TREE_CODE_CLASS (TREE_CODE (t)))
|
||
{
|
||
case '1':
|
||
return find_base_decl (TREE_OPERAND (t, 0));
|
||
|
||
case '2':
|
||
/* 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));
|
||
if (d0 == d1)
|
||
return d0;
|
||
else if (d0 == 0)
|
||
return d1;
|
||
else if (d1 == 0)
|
||
return d0;
|
||
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. */
|
||
|
||
int
|
||
can_address_p (t)
|
||
tree t;
|
||
{
|
||
/* If we're at the end, it is vacuously addressable. */
|
||
if (! handled_component_p (t))
|
||
return 1;
|
||
|
||
/* Bitfields are never addressable. */
|
||
else if (TREE_CODE (t) == BIT_FIELD_REF)
|
||
return 0;
|
||
|
||
/* 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;
|
||
|
||
/* 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;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return the alias set for T, which may be either a type or an
|
||
expression. Call language-specific routine for help, if needed. */
|
||
|
||
HOST_WIDE_INT
|
||
get_alias_set (t)
|
||
tree t;
|
||
{
|
||
HOST_WIDE_INT set;
|
||
|
||
/* If we're not doing any alias analysis, just assume everything
|
||
aliases everything else. Also return 0 if this or its type is
|
||
an error. */
|
||
if (! flag_strict_aliasing || t == error_mark_node
|
||
|| (! TYPE_P (t)
|
||
&& (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node)))
|
||
return 0;
|
||
|
||
/* We can be passed either an expression or a type. This and the
|
||
language-specific routine may make mutually-recursive calls to each other
|
||
to figure out what to do. At each juncture, we see if this is a tree
|
||
that the language may need to handle specially. First handle things that
|
||
aren't types. */
|
||
if (! TYPE_P (t))
|
||
{
|
||
tree inner = t;
|
||
tree placeholder_ptr = 0;
|
||
|
||
/* Remove any nops, then give the language a chance to do
|
||
something with this tree before we look at it. */
|
||
STRIP_NOPS (t);
|
||
set = (*lang_hooks.get_alias_set) (t);
|
||
if (set != -1)
|
||
return set;
|
||
|
||
/* First see if the actual object referenced is an INDIRECT_REF from a
|
||
restrict-qualified pointer or a "void *". Replace
|
||
PLACEHOLDER_EXPRs. */
|
||
while (TREE_CODE (inner) == PLACEHOLDER_EXPR
|
||
|| handled_component_p (inner))
|
||
{
|
||
if (TREE_CODE (inner) == PLACEHOLDER_EXPR)
|
||
inner = find_placeholder (inner, &placeholder_ptr);
|
||
else
|
||
inner = TREE_OPERAND (inner, 0);
|
||
|
||
STRIP_NOPS (inner);
|
||
}
|
||
|
||
/* Check for accesses through restrict-qualified pointers. */
|
||
if (TREE_CODE (inner) == INDIRECT_REF)
|
||
{
|
||
tree decl = find_base_decl (TREE_OPERAND (inner, 0));
|
||
|
||
if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl))
|
||
{
|
||
/* If we haven't computed the actual alias set, do it now. */
|
||
if (DECL_POINTER_ALIAS_SET (decl) == -2)
|
||
{
|
||
/* No two restricted pointers can point at the same thing.
|
||
However, a restricted pointer can point at the same thing
|
||
as an unrestricted pointer, if that unrestricted pointer
|
||
is based on the restricted pointer. So, we make the
|
||
alias set for the restricted pointer a subset of the
|
||
alias set for the type pointed to by the type of the
|
||
decl. */
|
||
HOST_WIDE_INT pointed_to_alias_set
|
||
= get_alias_set (TREE_TYPE (TREE_TYPE (decl)));
|
||
|
||
if (pointed_to_alias_set == 0)
|
||
/* It's not legal to make a subset of alias set zero. */
|
||
;
|
||
else
|
||
{
|
||
DECL_POINTER_ALIAS_SET (decl) = new_alias_set ();
|
||
record_alias_subset (pointed_to_alias_set,
|
||
DECL_POINTER_ALIAS_SET (decl));
|
||
}
|
||
}
|
||
|
||
/* We use the alias set indicated in the declaration. */
|
||
return DECL_POINTER_ALIAS_SET (decl);
|
||
}
|
||
|
||
/* If we have an INDIRECT_REF via a void pointer, we don't
|
||
know anything about what that might alias. */
|
||
else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE)
|
||
return 0;
|
||
}
|
||
|
||
/* Otherwise, pick up the outermost object that we could have a pointer
|
||
to, processing conversion and PLACEHOLDER_EXPR as above. */
|
||
placeholder_ptr = 0;
|
||
while (TREE_CODE (t) == PLACEHOLDER_EXPR
|
||
|| (handled_component_p (t) && ! can_address_p (t)))
|
||
{
|
||
if (TREE_CODE (t) == PLACEHOLDER_EXPR)
|
||
t = find_placeholder (t, &placeholder_ptr);
|
||
else
|
||
t = TREE_OPERAND (t, 0);
|
||
|
||
STRIP_NOPS (t);
|
||
}
|
||
|
||
/* If we've already determined the alias set for a decl, just return
|
||
it. This is necessary for C++ anonymous unions, whose component
|
||
variables don't look like union members (boo!). */
|
||
if (TREE_CODE (t) == VAR_DECL
|
||
&& DECL_RTL_SET_P (t) && GET_CODE (DECL_RTL (t)) == MEM)
|
||
return MEM_ALIAS_SET (DECL_RTL (t));
|
||
|
||
/* Now all we care about is the type. */
|
||
t = TREE_TYPE (t);
|
||
}
|
||
|
||
/* Variant qualifiers don't affect the alias set, so get the main
|
||
variant. If this is a type with a known alias set, return it. */
|
||
t = TYPE_MAIN_VARIANT (t);
|
||
if (TYPE_ALIAS_SET_KNOWN_P (t))
|
||
return TYPE_ALIAS_SET (t);
|
||
|
||
/* See if the language has special handling for this type. */
|
||
set = (*lang_hooks.get_alias_set) (t);
|
||
if (set != -1)
|
||
return set;
|
||
|
||
/* There are no objects of FUNCTION_TYPE, so there's no point in
|
||
using up an alias set for them. (There are, of course, pointers
|
||
and references to functions, but that's different.) */
|
||
else if (TREE_CODE (t) == FUNCTION_TYPE)
|
||
set = 0;
|
||
else
|
||
/* Otherwise make a new alias set for this type. */
|
||
set = new_alias_set ();
|
||
|
||
TYPE_ALIAS_SET (t) = set;
|
||
|
||
/* If this is an aggregate type, we must record any component aliasing
|
||
information. */
|
||
if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE)
|
||
record_component_aliases (t);
|
||
|
||
return set;
|
||
}
|
||
|
||
/* Return a brand-new alias set. */
|
||
|
||
HOST_WIDE_INT
|
||
new_alias_set ()
|
||
{
|
||
static HOST_WIDE_INT last_alias_set;
|
||
|
||
if (flag_strict_aliasing)
|
||
return ++last_alias_set;
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
/* Indicate that things in SUBSET can alias things in SUPERSET, but
|
||
not vice versa. For example, in C, a store to an `int' can alias a
|
||
structure containing an `int', but not vice versa. Here, the
|
||
structure would be the SUPERSET and `int' the SUBSET. This
|
||
function should be called only once per SUPERSET/SUBSET pair.
|
||
|
||
It is illegal for SUPERSET to be zero; everything is implicitly a
|
||
subset of alias set zero. */
|
||
|
||
void
|
||
record_alias_subset (superset, subset)
|
||
HOST_WIDE_INT superset;
|
||
HOST_WIDE_INT subset;
|
||
{
|
||
alias_set_entry superset_entry;
|
||
alias_set_entry subset_entry;
|
||
|
||
/* It is possible in complex type situations for both sets to be the same,
|
||
in which case we can ignore this operation. */
|
||
if (superset == subset)
|
||
return;
|
||
|
||
if (superset == 0)
|
||
abort ();
|
||
|
||
superset_entry = get_alias_set_entry (superset);
|
||
if (superset_entry == 0)
|
||
{
|
||
/* Create an entry for the SUPERSET, so that we have a place to
|
||
attach the SUBSET. */
|
||
superset_entry
|
||
= (alias_set_entry) xmalloc (sizeof (struct alias_set_entry));
|
||
superset_entry->alias_set = superset;
|
||
superset_entry->children
|
||
= splay_tree_new (splay_tree_compare_ints, 0, 0);
|
||
superset_entry->has_zero_child = 0;
|
||
splay_tree_insert (alias_sets, (splay_tree_key) superset,
|
||
(splay_tree_value) superset_entry);
|
||
}
|
||
|
||
if (subset == 0)
|
||
superset_entry->has_zero_child = 1;
|
||
else
|
||
{
|
||
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)
|
||
{
|
||
if (subset_entry->has_zero_child)
|
||
superset_entry->has_zero_child = 1;
|
||
|
||
splay_tree_foreach (subset_entry->children, insert_subset_children,
|
||
superset_entry->children);
|
||
}
|
||
|
||
/* Enter the SUBSET itself as a child of the SUPERSET. */
|
||
splay_tree_insert (superset_entry->children,
|
||
(splay_tree_key) subset, 0);
|
||
}
|
||
}
|
||
|
||
/* 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 marked addressable. For array types, we always
|
||
record the component types, so the front end should not call this
|
||
function if the individual component aren't addressable. */
|
||
|
||
void
|
||
record_component_aliases (type)
|
||
tree type;
|
||
{
|
||
HOST_WIDE_INT superset = get_alias_set (type);
|
||
tree field;
|
||
|
||
if (superset == 0)
|
||
return;
|
||
|
||
switch (TREE_CODE (type))
|
||
{
|
||
case ARRAY_TYPE:
|
||
if (! TYPE_NONALIASED_COMPONENT (type))
|
||
record_alias_subset (superset, get_alias_set (TREE_TYPE (type)));
|
||
break;
|
||
|
||
case RECORD_TYPE:
|
||
case UNION_TYPE:
|
||
case QUAL_UNION_TYPE:
|
||
for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field))
|
||
if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field))
|
||
record_alias_subset (superset, get_alias_set (TREE_TYPE (field)));
|
||
break;
|
||
|
||
case COMPLEX_TYPE:
|
||
record_alias_subset (superset, get_alias_set (TREE_TYPE (type)));
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Allocate an alias set for use in storing and reading from the varargs
|
||
spill area. */
|
||
|
||
HOST_WIDE_INT
|
||
get_varargs_alias_set ()
|
||
{
|
||
static HOST_WIDE_INT set = -1;
|
||
|
||
if (set == -1)
|
||
set = new_alias_set ();
|
||
|
||
return set;
|
||
}
|
||
|
||
/* Likewise, but used for the fixed portions of the frame, e.g., register
|
||
save areas. */
|
||
|
||
HOST_WIDE_INT
|
||
get_frame_alias_set ()
|
||
{
|
||
static HOST_WIDE_INT set = -1;
|
||
|
||
if (set == -1)
|
||
set = new_alias_set ();
|
||
|
||
return set;
|
||
}
|
||
|
||
/* Inside SRC, the source of a SET, find a base address. */
|
||
|
||
static rtx
|
||
find_base_value (src)
|
||
rtx src;
|
||
{
|
||
unsigned int regno;
|
||
|
||
switch (GET_CODE (src))
|
||
{
|
||
case SYMBOL_REF:
|
||
case LABEL_REF:
|
||
return src;
|
||
|
||
case REG:
|
||
regno = REGNO (src);
|
||
/* At the start of a function, argument registers have known base
|
||
values which may be lost later. Returning an ADDRESS
|
||
expression here allows optimization based on argument values
|
||
even when the argument registers are used for other purposes. */
|
||
if (regno < FIRST_PSEUDO_REGISTER && copying_arguments)
|
||
return new_reg_base_value[regno];
|
||
|
||
/* If a pseudo has a known base value, return it. Do not do this
|
||
for non-fixed hard regs since it can result in a circular
|
||
dependency chain for registers which have values at function entry.
|
||
|
||
The test above is not sufficient because the scheduler may move
|
||
a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */
|
||
if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno])
|
||
&& regno < reg_base_value_size
|
||
&& reg_base_value[regno])
|
||
return reg_base_value[regno];
|
||
|
||
return src;
|
||
|
||
case MEM:
|
||
/* Check for an argument passed in memory. Only record in the
|
||
copying-arguments block; it is too hard to track changes
|
||
otherwise. */
|
||
if (copying_arguments
|
||
&& (XEXP (src, 0) == arg_pointer_rtx
|
||
|| (GET_CODE (XEXP (src, 0)) == PLUS
|
||
&& XEXP (XEXP (src, 0), 0) == arg_pointer_rtx)))
|
||
return gen_rtx_ADDRESS (VOIDmode, src);
|
||
return 0;
|
||
|
||
case CONST:
|
||
src = XEXP (src, 0);
|
||
if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
|
||
break;
|
||
|
||
/* ... fall through ... */
|
||
|
||
case PLUS:
|
||
case MINUS:
|
||
{
|
||
rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1);
|
||
|
||
/* If either operand is a REG that is a known pointer, then it
|
||
is the base. */
|
||
if (REG_P (src_0) && REG_POINTER (src_0))
|
||
return find_base_value (src_0);
|
||
if (REG_P (src_1) && REG_POINTER (src_1))
|
||
return find_base_value (src_1);
|
||
|
||
/* If either operand is a REG, then see if we already have
|
||
a known value for it. */
|
||
if (REG_P (src_0))
|
||
{
|
||
temp = find_base_value (src_0);
|
||
if (temp != 0)
|
||
src_0 = temp;
|
||
}
|
||
|
||
if (REG_P (src_1))
|
||
{
|
||
temp = find_base_value (src_1);
|
||
if (temp!= 0)
|
||
src_1 = temp;
|
||
}
|
||
|
||
/* If either base is named object or a special address
|
||
(like an argument or stack reference), then use it for the
|
||
base term. */
|
||
if (src_0 != 0
|
||
&& (GET_CODE (src_0) == SYMBOL_REF
|
||
|| GET_CODE (src_0) == LABEL_REF
|
||
|| (GET_CODE (src_0) == ADDRESS
|
||
&& GET_MODE (src_0) != VOIDmode)))
|
||
return src_0;
|
||
|
||
if (src_1 != 0
|
||
&& (GET_CODE (src_1) == SYMBOL_REF
|
||
|| GET_CODE (src_1) == LABEL_REF
|
||
|| (GET_CODE (src_1) == ADDRESS
|
||
&& GET_MODE (src_1) != VOIDmode)))
|
||
return src_1;
|
||
|
||
/* Guess which operand is the base address:
|
||
If either operand is a symbol, then it is the base. If
|
||
either operand is a CONST_INT, then the other is the base. */
|
||
if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0))
|
||
return find_base_value (src_0);
|
||
else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1))
|
||
return find_base_value (src_1);
|
||
|
||
return 0;
|
||
}
|
||
|
||
case LO_SUM:
|
||
/* The standard form is (lo_sum reg sym) so look only at the
|
||
second operand. */
|
||
return find_base_value (XEXP (src, 1));
|
||
|
||
case AND:
|
||
/* If the second operand is constant set the base
|
||
address to the first operand. */
|
||
if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0)
|
||
return find_base_value (XEXP (src, 0));
|
||
return 0;
|
||
|
||
case TRUNCATE:
|
||
if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode))
|
||
break;
|
||
/* Fall through. */
|
||
case HIGH:
|
||
case PRE_INC:
|
||
case PRE_DEC:
|
||
case POST_INC:
|
||
case POST_DEC:
|
||
case PRE_MODIFY:
|
||
case POST_MODIFY:
|
||
return find_base_value (XEXP (src, 0));
|
||
|
||
case ZERO_EXTEND:
|
||
case SIGN_EXTEND: /* used for NT/Alpha pointers */
|
||
{
|
||
rtx temp = find_base_value (XEXP (src, 0));
|
||
|
||
#ifdef POINTERS_EXTEND_UNSIGNED
|
||
if (temp != 0 && CONSTANT_P (temp) && GET_MODE (temp) != Pmode)
|
||
temp = convert_memory_address (Pmode, temp);
|
||
#endif
|
||
|
||
return temp;
|
||
}
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Called from init_alias_analysis indirectly through note_stores. */
|
||
|
||
/* While scanning insns to find base values, reg_seen[N] is nonzero if
|
||
register N has been set in this function. */
|
||
static char *reg_seen;
|
||
|
||
/* Addresses which are known not to alias anything else are identified
|
||
by a unique integer. */
|
||
static int unique_id;
|
||
|
||
static void
|
||
record_set (dest, set, data)
|
||
rtx dest, set;
|
||
void *data ATTRIBUTE_UNUSED;
|
||
{
|
||
unsigned regno;
|
||
rtx src;
|
||
|
||
if (GET_CODE (dest) != REG)
|
||
return;
|
||
|
||
regno = REGNO (dest);
|
||
|
||
if (regno >= reg_base_value_size)
|
||
abort ();
|
||
|
||
if (set)
|
||
{
|
||
/* A CLOBBER wipes out any old value but does not prevent a previously
|
||
unset register from acquiring a base address (i.e. reg_seen is not
|
||
set). */
|
||
if (GET_CODE (set) == CLOBBER)
|
||
{
|
||
new_reg_base_value[regno] = 0;
|
||
return;
|
||
}
|
||
src = SET_SRC (set);
|
||
}
|
||
else
|
||
{
|
||
if (reg_seen[regno])
|
||
{
|
||
new_reg_base_value[regno] = 0;
|
||
return;
|
||
}
|
||
reg_seen[regno] = 1;
|
||
new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode,
|
||
GEN_INT (unique_id++));
|
||
return;
|
||
}
|
||
|
||
/* This is not the first set. If the new value is not related to the
|
||
old value, forget the base value. Note that the following code is
|
||
not detected:
|
||
extern int x, y; int *p = &x; p += (&y-&x);
|
||
ANSI C does not allow computing the difference of addresses
|
||
of distinct top level objects. */
|
||
if (new_reg_base_value[regno])
|
||
switch (GET_CODE (src))
|
||
{
|
||
case LO_SUM:
|
||
case MINUS:
|
||
if (XEXP (src, 0) != dest && XEXP (src, 1) != dest)
|
||
new_reg_base_value[regno] = 0;
|
||
break;
|
||
case PLUS:
|
||
/* If the value we add in the PLUS is also a valid base value,
|
||
this might be the actual base value, and the original value
|
||
an index. */
|
||
{
|
||
rtx other = NULL_RTX;
|
||
|
||
if (XEXP (src, 0) == dest)
|
||
other = XEXP (src, 1);
|
||
else if (XEXP (src, 1) == dest)
|
||
other = XEXP (src, 0);
|
||
|
||
if (! other || find_base_value (other))
|
||
new_reg_base_value[regno] = 0;
|
||
break;
|
||
}
|
||
case AND:
|
||
if (XEXP (src, 0) != dest || GET_CODE (XEXP (src, 1)) != CONST_INT)
|
||
new_reg_base_value[regno] = 0;
|
||
break;
|
||
default:
|
||
new_reg_base_value[regno] = 0;
|
||
break;
|
||
}
|
||
/* If this is the first set of a register, record the value. */
|
||
else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
|
||
&& ! reg_seen[regno] && new_reg_base_value[regno] == 0)
|
||
new_reg_base_value[regno] = find_base_value (src);
|
||
|
||
reg_seen[regno] = 1;
|
||
}
|
||
|
||
/* Called from loop optimization when a new pseudo-register is
|
||
created. It indicates that REGNO is being set to VAL. f INVARIANT
|
||
is true then this value also describes an invariant relationship
|
||
which can be used to deduce that two registers with unknown values
|
||
are different. */
|
||
|
||
void
|
||
record_base_value (regno, val, invariant)
|
||
unsigned int regno;
|
||
rtx val;
|
||
int invariant;
|
||
{
|
||
if (regno >= reg_base_value_size)
|
||
return;
|
||
|
||
if (invariant && alias_invariant)
|
||
alias_invariant[regno] = val;
|
||
|
||
if (GET_CODE (val) == REG)
|
||
{
|
||
if (REGNO (val) < reg_base_value_size)
|
||
reg_base_value[regno] = reg_base_value[REGNO (val)];
|
||
|
||
return;
|
||
}
|
||
|
||
reg_base_value[regno] = find_base_value (val);
|
||
}
|
||
|
||
/* Clear alias info for a register. This is used if an RTL transformation
|
||
changes the value of a register. This is used in flow by AUTO_INC_DEC
|
||
optimizations. We don't need to clear reg_base_value, since flow only
|
||
changes the offset. */
|
||
|
||
void
|
||
clear_reg_alias_info (reg)
|
||
rtx reg;
|
||
{
|
||
unsigned int regno = REGNO (reg);
|
||
|
||
if (regno < reg_known_value_size && regno >= FIRST_PSEUDO_REGISTER)
|
||
reg_known_value[regno] = reg;
|
||
}
|
||
|
||
/* Returns a canonical version of X, from the point of view alias
|
||
analysis. (For example, if X is a MEM whose address is a register,
|
||
and the register has a known value (say a SYMBOL_REF), then a MEM
|
||
whose address is the SYMBOL_REF is returned.) */
|
||
|
||
rtx
|
||
canon_rtx (x)
|
||
rtx x;
|
||
{
|
||
/* Recursively look for equivalences. */
|
||
if (GET_CODE (x) == REG && REGNO (x) >= FIRST_PSEUDO_REGISTER
|
||
&& REGNO (x) < reg_known_value_size)
|
||
return reg_known_value[REGNO (x)] == x
|
||
? x : canon_rtx (reg_known_value[REGNO (x)]);
|
||
else if (GET_CODE (x) == PLUS)
|
||
{
|
||
rtx x0 = canon_rtx (XEXP (x, 0));
|
||
rtx x1 = canon_rtx (XEXP (x, 1));
|
||
|
||
if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1))
|
||
{
|
||
if (GET_CODE (x0) == CONST_INT)
|
||
return plus_constant (x1, INTVAL (x0));
|
||
else if (GET_CODE (x1) == CONST_INT)
|
||
return plus_constant (x0, INTVAL (x1));
|
||
return gen_rtx_PLUS (GET_MODE (x), x0, x1);
|
||
}
|
||
}
|
||
|
||
/* This gives us much better alias analysis when called from
|
||
the loop optimizer. Note we want to leave the original
|
||
MEM alone, but need to return the canonicalized MEM with
|
||
all the flags with their original values. */
|
||
else if (GET_CODE (x) == MEM)
|
||
x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0)));
|
||
|
||
return x;
|
||
}
|
||
|
||
/* Return 1 if X and Y are identical-looking rtx's.
|
||
|
||
We use the data in reg_known_value above to see if two registers with
|
||
different numbers are, in fact, equivalent. */
|
||
|
||
static int
|
||
rtx_equal_for_memref_p (x, y)
|
||
rtx x, y;
|
||
{
|
||
int i;
|
||
int j;
|
||
enum rtx_code code;
|
||
const char *fmt;
|
||
|
||
if (x == 0 && y == 0)
|
||
return 1;
|
||
if (x == 0 || y == 0)
|
||
return 0;
|
||
|
||
x = canon_rtx (x);
|
||
y = canon_rtx (y);
|
||
|
||
if (x == y)
|
||
return 1;
|
||
|
||
code = GET_CODE (x);
|
||
/* Rtx's of different codes cannot be equal. */
|
||
if (code != GET_CODE (y))
|
||
return 0;
|
||
|
||
/* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
|
||
(REG:SI x) and (REG:HI x) are NOT equivalent. */
|
||
|
||
if (GET_MODE (x) != GET_MODE (y))
|
||
return 0;
|
||
|
||
/* Some RTL can be compared without a recursive examination. */
|
||
switch (code)
|
||
{
|
||
case VALUE:
|
||
return CSELIB_VAL_PTR (x) == CSELIB_VAL_PTR (y);
|
||
|
||
case REG:
|
||
return REGNO (x) == REGNO (y);
|
||
|
||
case LABEL_REF:
|
||
return XEXP (x, 0) == XEXP (y, 0);
|
||
|
||
case SYMBOL_REF:
|
||
return XSTR (x, 0) == XSTR (y, 0);
|
||
|
||
case CONST_INT:
|
||
case CONST_DOUBLE:
|
||
/* There's no need to compare the contents of CONST_DOUBLEs or
|
||
CONST_INTs because pointer equality is a good enough
|
||
comparison for these nodes. */
|
||
return 0;
|
||
|
||
case ADDRESSOF:
|
||
return (XINT (x, 1) == XINT (y, 1)
|
||
&& rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)));
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* For commutative operations, the RTX match if the operand match in any
|
||
order. Also handle the simple binary and unary cases without a loop. */
|
||
if (code == EQ || code == NE || GET_RTX_CLASS (code) == 'c')
|
||
return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))
|
||
&& rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1)))
|
||
|| (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1))
|
||
&& rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0))));
|
||
else if (GET_RTX_CLASS (code) == '<' || GET_RTX_CLASS (code) == '2')
|
||
return (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))
|
||
&& rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1)));
|
||
else if (GET_RTX_CLASS (code) == '1')
|
||
return rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0));
|
||
|
||
/* Compare the elements. If any pair of corresponding elements
|
||
fail to match, return 0 for the whole things.
|
||
|
||
Limit cases to types which actually appear in addresses. */
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
switch (fmt[i])
|
||
{
|
||
case 'i':
|
||
if (XINT (x, i) != XINT (y, i))
|
||
return 0;
|
||
break;
|
||
|
||
case 'E':
|
||
/* Two vectors must have the same length. */
|
||
if (XVECLEN (x, i) != XVECLEN (y, i))
|
||
return 0;
|
||
|
||
/* And the corresponding elements must match. */
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
if (rtx_equal_for_memref_p (XVECEXP (x, i, j),
|
||
XVECEXP (y, i, j)) == 0)
|
||
return 0;
|
||
break;
|
||
|
||
case 'e':
|
||
if (rtx_equal_for_memref_p (XEXP (x, i), XEXP (y, i)) == 0)
|
||
return 0;
|
||
break;
|
||
|
||
/* This can happen for asm operands. */
|
||
case 's':
|
||
if (strcmp (XSTR (x, i), XSTR (y, i)))
|
||
return 0;
|
||
break;
|
||
|
||
/* This can happen for an asm which clobbers memory. */
|
||
case '0':
|
||
break;
|
||
|
||
/* It is believed that rtx's at this level will never
|
||
contain anything but integers and other rtx's,
|
||
except for within LABEL_REFs and SYMBOL_REFs. */
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
return 1;
|
||
}
|
||
|
||
/* Given an rtx X, find a SYMBOL_REF or LABEL_REF within
|
||
X and return it, or return 0 if none found. */
|
||
|
||
static rtx
|
||
find_symbolic_term (x)
|
||
rtx x;
|
||
{
|
||
int i;
|
||
enum rtx_code code;
|
||
const char *fmt;
|
||
|
||
code = GET_CODE (x);
|
||
if (code == SYMBOL_REF || code == LABEL_REF)
|
||
return x;
|
||
if (GET_RTX_CLASS (code) == 'o')
|
||
return 0;
|
||
|
||
fmt = GET_RTX_FORMAT (code);
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
rtx t;
|
||
|
||
if (fmt[i] == 'e')
|
||
{
|
||
t = find_symbolic_term (XEXP (x, i));
|
||
if (t != 0)
|
||
return t;
|
||
}
|
||
else if (fmt[i] == 'E')
|
||
break;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
static rtx
|
||
find_base_term (x)
|
||
rtx x;
|
||
{
|
||
cselib_val *val;
|
||
struct elt_loc_list *l;
|
||
|
||
#if defined (FIND_BASE_TERM)
|
||
/* Try machine-dependent ways to find the base term. */
|
||
x = FIND_BASE_TERM (x);
|
||
#endif
|
||
|
||
switch (GET_CODE (x))
|
||
{
|
||
case REG:
|
||
return REG_BASE_VALUE (x);
|
||
|
||
case TRUNCATE:
|
||
if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode))
|
||
return 0;
|
||
/* Fall through. */
|
||
case HIGH:
|
||
case PRE_INC:
|
||
case PRE_DEC:
|
||
case POST_INC:
|
||
case POST_DEC:
|
||
case PRE_MODIFY:
|
||
case POST_MODIFY:
|
||
return find_base_term (XEXP (x, 0));
|
||
|
||
case ZERO_EXTEND:
|
||
case SIGN_EXTEND: /* Used for Alpha/NT pointers */
|
||
{
|
||
rtx temp = find_base_term (XEXP (x, 0));
|
||
|
||
#ifdef POINTERS_EXTEND_UNSIGNED
|
||
if (temp != 0 && CONSTANT_P (temp) && GET_MODE (temp) != Pmode)
|
||
temp = convert_memory_address (Pmode, temp);
|
||
#endif
|
||
|
||
return temp;
|
||
}
|
||
|
||
case VALUE:
|
||
val = CSELIB_VAL_PTR (x);
|
||
for (l = val->locs; l; l = l->next)
|
||
if ((x = find_base_term (l->loc)) != 0)
|
||
return x;
|
||
return 0;
|
||
|
||
case CONST:
|
||
x = XEXP (x, 0);
|
||
if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS)
|
||
return 0;
|
||
/* fall through */
|
||
case LO_SUM:
|
||
case PLUS:
|
||
case MINUS:
|
||
{
|
||
rtx tmp1 = XEXP (x, 0);
|
||
rtx tmp2 = XEXP (x, 1);
|
||
|
||
/* This is a little bit tricky since we have to determine which of
|
||
the two operands represents the real base address. Otherwise this
|
||
routine may return the index register instead of the base register.
|
||
|
||
That may cause us to believe no aliasing was possible, when in
|
||
fact aliasing is possible.
|
||
|
||
We use a few simple tests to guess the base register. Additional
|
||
tests can certainly be added. For example, if one of the operands
|
||
is a shift or multiply, then it must be the index register and the
|
||
other operand is the base register. */
|
||
|
||
if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2))
|
||
return find_base_term (tmp2);
|
||
|
||
/* If either operand is known to be a pointer, then use it
|
||
to determine the base term. */
|
||
if (REG_P (tmp1) && REG_POINTER (tmp1))
|
||
return find_base_term (tmp1);
|
||
|
||
if (REG_P (tmp2) && REG_POINTER (tmp2))
|
||
return find_base_term (tmp2);
|
||
|
||
/* Neither operand was known to be a pointer. Go ahead and find the
|
||
base term for both operands. */
|
||
tmp1 = find_base_term (tmp1);
|
||
tmp2 = find_base_term (tmp2);
|
||
|
||
/* If either base term is named object or a special address
|
||
(like an argument or stack reference), then use it for the
|
||
base term. */
|
||
if (tmp1 != 0
|
||
&& (GET_CODE (tmp1) == SYMBOL_REF
|
||
|| GET_CODE (tmp1) == LABEL_REF
|
||
|| (GET_CODE (tmp1) == ADDRESS
|
||
&& GET_MODE (tmp1) != VOIDmode)))
|
||
return tmp1;
|
||
|
||
if (tmp2 != 0
|
||
&& (GET_CODE (tmp2) == SYMBOL_REF
|
||
|| GET_CODE (tmp2) == LABEL_REF
|
||
|| (GET_CODE (tmp2) == ADDRESS
|
||
&& GET_MODE (tmp2) != VOIDmode)))
|
||
return tmp2;
|
||
|
||
/* We could not determine which of the two operands was the
|
||
base register and which was the index. So we can determine
|
||
nothing from the base alias check. */
|
||
return 0;
|
||
}
|
||
|
||
case AND:
|
||
if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) != 0)
|
||
return find_base_term (XEXP (x, 0));
|
||
return 0;
|
||
|
||
case SYMBOL_REF:
|
||
case LABEL_REF:
|
||
return x;
|
||
|
||
case ADDRESSOF:
|
||
return REG_BASE_VALUE (frame_pointer_rtx);
|
||
|
||
default:
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
/* Return 0 if the addresses X and Y are known to point to different
|
||
objects, 1 if they might be pointers to the same object. */
|
||
|
||
static int
|
||
base_alias_check (x, y, x_mode, y_mode)
|
||
rtx x, y;
|
||
enum machine_mode x_mode, y_mode;
|
||
{
|
||
rtx x_base = find_base_term (x);
|
||
rtx y_base = find_base_term (y);
|
||
|
||
/* If the address itself has no known base see if a known equivalent
|
||
value has one. If either address still has no known base, nothing
|
||
is known about aliasing. */
|
||
if (x_base == 0)
|
||
{
|
||
rtx x_c;
|
||
|
||
if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x)
|
||
return 1;
|
||
|
||
x_base = find_base_term (x_c);
|
||
if (x_base == 0)
|
||
return 1;
|
||
}
|
||
|
||
if (y_base == 0)
|
||
{
|
||
rtx y_c;
|
||
if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y)
|
||
return 1;
|
||
|
||
y_base = find_base_term (y_c);
|
||
if (y_base == 0)
|
||
return 1;
|
||
}
|
||
|
||
/* If the base addresses are equal nothing is known about aliasing. */
|
||
if (rtx_equal_p (x_base, y_base))
|
||
return 1;
|
||
|
||
/* The base addresses of the read and write are different expressions.
|
||
If they are both symbols and they are not accessed via AND, there is
|
||
no conflict. We can bring knowledge of object alignment into play
|
||
here. For example, on alpha, "char a, b;" can alias one another,
|
||
though "char a; long b;" cannot. */
|
||
if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS)
|
||
{
|
||
if (GET_CODE (x) == AND && GET_CODE (y) == AND)
|
||
return 1;
|
||
if (GET_CODE (x) == AND
|
||
&& (GET_CODE (XEXP (x, 1)) != CONST_INT
|
||
|| (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1))))
|
||
return 1;
|
||
if (GET_CODE (y) == AND
|
||
&& (GET_CODE (XEXP (y, 1)) != CONST_INT
|
||
|| (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
|
||
return 1;
|
||
/* Differing symbols never alias. */
|
||
return 0;
|
||
}
|
||
|
||
/* If one address is a stack reference there can be no alias:
|
||
stack references using different base registers do not alias,
|
||
a stack reference can not alias a parameter, and a stack reference
|
||
can not alias a global. */
|
||
if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode)
|
||
|| (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode))
|
||
return 0;
|
||
|
||
if (! flag_argument_noalias)
|
||
return 1;
|
||
|
||
if (flag_argument_noalias > 1)
|
||
return 0;
|
||
|
||
/* Weak noalias assertion (arguments are distinct, but may match globals). */
|
||
return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode);
|
||
}
|
||
|
||
/* Convert the address X into something we can use. This is done by returning
|
||
it unchanged unless it is a value; in the latter case we call cselib to get
|
||
a more useful rtx. */
|
||
|
||
rtx
|
||
get_addr (x)
|
||
rtx x;
|
||
{
|
||
cselib_val *v;
|
||
struct elt_loc_list *l;
|
||
|
||
if (GET_CODE (x) != VALUE)
|
||
return x;
|
||
v = CSELIB_VAL_PTR (x);
|
||
for (l = v->locs; l; l = l->next)
|
||
if (CONSTANT_P (l->loc))
|
||
return l->loc;
|
||
for (l = v->locs; l; l = l->next)
|
||
if (GET_CODE (l->loc) != REG && GET_CODE (l->loc) != MEM)
|
||
return l->loc;
|
||
if (v->locs)
|
||
return v->locs->loc;
|
||
return x;
|
||
}
|
||
|
||
/* Return the address of the (N_REFS + 1)th memory reference to ADDR
|
||
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
|
||
addr_side_effect_eval (addr, size, n_refs)
|
||
rtx addr;
|
||
int size;
|
||
int n_refs;
|
||
{
|
||
int offset = 0;
|
||
|
||
switch (GET_CODE (addr))
|
||
{
|
||
case PRE_INC:
|
||
offset = (n_refs + 1) * size;
|
||
break;
|
||
case PRE_DEC:
|
||
offset = -(n_refs + 1) * size;
|
||
break;
|
||
case POST_INC:
|
||
offset = n_refs * size;
|
||
break;
|
||
case POST_DEC:
|
||
offset = -n_refs * size;
|
||
break;
|
||
|
||
default:
|
||
return addr;
|
||
}
|
||
|
||
if (offset)
|
||
addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), GEN_INT (offset));
|
||
else
|
||
addr = XEXP (addr, 0);
|
||
|
||
return addr;
|
||
}
|
||
|
||
/* Return nonzero if X and Y (memory addresses) could reference the
|
||
same location in memory. C is an offset accumulator. When
|
||
C is nonzero, we are testing aliases between X and Y + C.
|
||
XSIZE is the size in bytes of the X reference,
|
||
similarly YSIZE is the size in bytes for Y.
|
||
|
||
If XSIZE or YSIZE is zero, we do not know the amount of memory being
|
||
referenced (the reference was BLKmode), so make the most pessimistic
|
||
assumptions.
|
||
|
||
If XSIZE or YSIZE is negative, we may access memory outside the object
|
||
being referenced as a side effect. This can happen when using AND to
|
||
align memory references, as is done on the Alpha.
|
||
|
||
Nice to notice that varying addresses cannot conflict with fp if no
|
||
local variables had their addresses taken, but that's too hard now. */
|
||
|
||
static int
|
||
memrefs_conflict_p (xsize, x, ysize, y, c)
|
||
rtx x, y;
|
||
int xsize, ysize;
|
||
HOST_WIDE_INT c;
|
||
{
|
||
if (GET_CODE (x) == VALUE)
|
||
x = get_addr (x);
|
||
if (GET_CODE (y) == VALUE)
|
||
y = get_addr (y);
|
||
if (GET_CODE (x) == HIGH)
|
||
x = XEXP (x, 0);
|
||
else if (GET_CODE (x) == LO_SUM)
|
||
x = XEXP (x, 1);
|
||
else
|
||
x = canon_rtx (addr_side_effect_eval (x, xsize, 0));
|
||
if (GET_CODE (y) == HIGH)
|
||
y = XEXP (y, 0);
|
||
else if (GET_CODE (y) == LO_SUM)
|
||
y = XEXP (y, 1);
|
||
else
|
||
y = canon_rtx (addr_side_effect_eval (y, ysize, 0));
|
||
|
||
if (rtx_equal_for_memref_p (x, y))
|
||
{
|
||
if (xsize <= 0 || ysize <= 0)
|
||
return 1;
|
||
if (c >= 0 && xsize > c)
|
||
return 1;
|
||
if (c < 0 && ysize+c > 0)
|
||
return 1;
|
||
return 0;
|
||
}
|
||
|
||
/* This code used to check for conflicts involving stack references and
|
||
globals but the base address alias code now handles these cases. */
|
||
|
||
if (GET_CODE (x) == PLUS)
|
||
{
|
||
/* The fact that X is canonicalized means that this
|
||
PLUS rtx is canonicalized. */
|
||
rtx x0 = XEXP (x, 0);
|
||
rtx x1 = XEXP (x, 1);
|
||
|
||
if (GET_CODE (y) == PLUS)
|
||
{
|
||
/* The fact that Y is canonicalized means that this
|
||
PLUS rtx is canonicalized. */
|
||
rtx y0 = XEXP (y, 0);
|
||
rtx y1 = XEXP (y, 1);
|
||
|
||
if (rtx_equal_for_memref_p (x1, y1))
|
||
return memrefs_conflict_p (xsize, x0, ysize, y0, c);
|
||
if (rtx_equal_for_memref_p (x0, y0))
|
||
return memrefs_conflict_p (xsize, x1, ysize, y1, c);
|
||
if (GET_CODE (x1) == CONST_INT)
|
||
{
|
||
if (GET_CODE (y1) == CONST_INT)
|
||
return memrefs_conflict_p (xsize, x0, ysize, y0,
|
||
c - INTVAL (x1) + INTVAL (y1));
|
||
else
|
||
return memrefs_conflict_p (xsize, x0, ysize, y,
|
||
c - INTVAL (x1));
|
||
}
|
||
else if (GET_CODE (y1) == CONST_INT)
|
||
return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
|
||
|
||
return 1;
|
||
}
|
||
else if (GET_CODE (x1) == CONST_INT)
|
||
return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1));
|
||
}
|
||
else if (GET_CODE (y) == PLUS)
|
||
{
|
||
/* The fact that Y is canonicalized means that this
|
||
PLUS rtx is canonicalized. */
|
||
rtx y0 = XEXP (y, 0);
|
||
rtx y1 = XEXP (y, 1);
|
||
|
||
if (GET_CODE (y1) == CONST_INT)
|
||
return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
|
||
else
|
||
return 1;
|
||
}
|
||
|
||
if (GET_CODE (x) == GET_CODE (y))
|
||
switch (GET_CODE (x))
|
||
{
|
||
case MULT:
|
||
{
|
||
/* Handle cases where we expect the second operands to be the
|
||
same, and check only whether the first operand would conflict
|
||
or not. */
|
||
rtx x0, y0;
|
||
rtx x1 = canon_rtx (XEXP (x, 1));
|
||
rtx y1 = canon_rtx (XEXP (y, 1));
|
||
if (! rtx_equal_for_memref_p (x1, y1))
|
||
return 1;
|
||
x0 = canon_rtx (XEXP (x, 0));
|
||
y0 = canon_rtx (XEXP (y, 0));
|
||
if (rtx_equal_for_memref_p (x0, y0))
|
||
return (xsize == 0 || ysize == 0
|
||
|| (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0));
|
||
|
||
/* Can't properly adjust our sizes. */
|
||
if (GET_CODE (x1) != CONST_INT)
|
||
return 1;
|
||
xsize /= INTVAL (x1);
|
||
ysize /= INTVAL (x1);
|
||
c /= INTVAL (x1);
|
||
return memrefs_conflict_p (xsize, x0, ysize, y0, c);
|
||
}
|
||
|
||
case REG:
|
||
/* Are these registers known not to be equal? */
|
||
if (alias_invariant)
|
||
{
|
||
unsigned int r_x = REGNO (x), r_y = REGNO (y);
|
||
rtx i_x, i_y; /* invariant relationships of X and Y */
|
||
|
||
i_x = r_x >= reg_base_value_size ? 0 : alias_invariant[r_x];
|
||
i_y = r_y >= reg_base_value_size ? 0 : alias_invariant[r_y];
|
||
|
||
if (i_x == 0 && i_y == 0)
|
||
break;
|
||
|
||
if (! memrefs_conflict_p (xsize, i_x ? i_x : x,
|
||
ysize, i_y ? i_y : y, c))
|
||
return 0;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* Treat an access through an AND (e.g. a subword access on an Alpha)
|
||
as an access with indeterminate size. Assume that references
|
||
besides AND are aligned, so if the size of the other reference is
|
||
at least as large as the alignment, assume no other overlap. */
|
||
if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT)
|
||
{
|
||
if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1)))
|
||
xsize = -1;
|
||
return memrefs_conflict_p (xsize, XEXP (x, 0), ysize, y, c);
|
||
}
|
||
if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT)
|
||
{
|
||
/* ??? If we are indexing far enough into the array/structure, we
|
||
may yet be able to determine that we can not overlap. But we
|
||
also need to that we are far enough from the end not to overlap
|
||
a following reference, so we do nothing with that for now. */
|
||
if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1)))
|
||
ysize = -1;
|
||
return memrefs_conflict_p (xsize, x, ysize, XEXP (y, 0), c);
|
||
}
|
||
|
||
if (GET_CODE (x) == ADDRESSOF)
|
||
{
|
||
if (y == frame_pointer_rtx
|
||
|| GET_CODE (y) == ADDRESSOF)
|
||
return xsize <= 0 || ysize <= 0;
|
||
}
|
||
if (GET_CODE (y) == ADDRESSOF)
|
||
{
|
||
if (x == frame_pointer_rtx)
|
||
return xsize <= 0 || ysize <= 0;
|
||
}
|
||
|
||
if (CONSTANT_P (x))
|
||
{
|
||
if (GET_CODE (x) == CONST_INT && GET_CODE (y) == CONST_INT)
|
||
{
|
||
c += (INTVAL (y) - INTVAL (x));
|
||
return (xsize <= 0 || ysize <= 0
|
||
|| (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0));
|
||
}
|
||
|
||
if (GET_CODE (x) == CONST)
|
||
{
|
||
if (GET_CODE (y) == CONST)
|
||
return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
|
||
ysize, canon_rtx (XEXP (y, 0)), c);
|
||
else
|
||
return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
|
||
ysize, y, c);
|
||
}
|
||
if (GET_CODE (y) == CONST)
|
||
return memrefs_conflict_p (xsize, x, ysize,
|
||
canon_rtx (XEXP (y, 0)), c);
|
||
|
||
if (CONSTANT_P (y))
|
||
return (xsize <= 0 || ysize <= 0
|
||
|| (rtx_equal_for_memref_p (x, y)
|
||
&& ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0))));
|
||
|
||
return 1;
|
||
}
|
||
return 1;
|
||
}
|
||
|
||
/* Functions to compute memory dependencies.
|
||
|
||
Since we process the insns in execution order, we can build tables
|
||
to keep track of what registers are fixed (and not aliased), what registers
|
||
are varying in known ways, and what registers are varying in unknown
|
||
ways.
|
||
|
||
If both memory references are volatile, then there must always be a
|
||
dependence between the two references, since their order can not be
|
||
changed. A volatile and non-volatile reference can be interchanged
|
||
though.
|
||
|
||
A MEM_IN_STRUCT reference at a non-AND varying address can never
|
||
conflict with a non-MEM_IN_STRUCT reference at a fixed address. We
|
||
also must allow AND addresses, because they may generate accesses
|
||
outside the object being referenced. This is used to generate
|
||
aligned addresses from unaligned addresses, for instance, the alpha
|
||
storeqi_unaligned pattern. */
|
||
|
||
/* Read dependence: X is read after read in MEM takes place. There can
|
||
only be a dependence here if both reads are volatile. */
|
||
|
||
int
|
||
read_dependence (mem, x)
|
||
rtx mem;
|
||
rtx x;
|
||
{
|
||
return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem);
|
||
}
|
||
|
||
/* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and
|
||
MEM2 is a reference to a structure at a varying address, or returns
|
||
MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL
|
||
value is returned MEM1 and MEM2 can never alias. VARIES_P is used
|
||
to decide whether or not an address may vary; it should return
|
||
nonzero whenever variation is possible.
|
||
MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */
|
||
|
||
static rtx
|
||
fixed_scalar_and_varying_struct_p (mem1, mem2, mem1_addr, mem2_addr, varies_p)
|
||
rtx mem1, mem2;
|
||
rtx mem1_addr, mem2_addr;
|
||
int (*varies_p) PARAMS ((rtx, int));
|
||
{
|
||
if (! flag_strict_aliasing)
|
||
return NULL_RTX;
|
||
|
||
if (MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2)
|
||
&& !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1))
|
||
/* MEM1 is a scalar at a fixed address; MEM2 is a struct at a
|
||
varying address. */
|
||
return mem1;
|
||
|
||
if (MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2)
|
||
&& varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1))
|
||
/* MEM2 is a scalar at a fixed address; MEM1 is a struct at a
|
||
varying address. */
|
||
return mem2;
|
||
|
||
return NULL_RTX;
|
||
}
|
||
|
||
/* Returns nonzero if something about the mode or address format MEM1
|
||
indicates that it might well alias *anything*. */
|
||
|
||
static int
|
||
aliases_everything_p (mem)
|
||
rtx mem;
|
||
{
|
||
if (GET_CODE (XEXP (mem, 0)) == AND)
|
||
/* If the address is an AND, its very hard to know at what it is
|
||
actually pointing. */
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return true if we can determine that the fields referenced cannot
|
||
overlap for any pair of objects. */
|
||
|
||
static bool
|
||
nonoverlapping_component_refs_p (x, y)
|
||
tree x, y;
|
||
{
|
||
tree fieldx, fieldy, typex, typey, orig_y;
|
||
|
||
do
|
||
{
|
||
/* The comparison has to be done at a common type, since we don't
|
||
know how the inheritance hierarchy works. */
|
||
orig_y = y;
|
||
do
|
||
{
|
||
fieldx = TREE_OPERAND (x, 1);
|
||
typex = DECL_FIELD_CONTEXT (fieldx);
|
||
|
||
y = orig_y;
|
||
do
|
||
{
|
||
fieldy = TREE_OPERAND (y, 1);
|
||
typey = DECL_FIELD_CONTEXT (fieldy);
|
||
|
||
if (typex == typey)
|
||
goto found;
|
||
|
||
y = TREE_OPERAND (y, 0);
|
||
}
|
||
while (y && TREE_CODE (y) == COMPONENT_REF);
|
||
|
||
x = TREE_OPERAND (x, 0);
|
||
}
|
||
while (x && TREE_CODE (x) == COMPONENT_REF);
|
||
|
||
/* Never found a common type. */
|
||
return false;
|
||
|
||
found:
|
||
/* If we're left with accessing different fields of a structure,
|
||
then no overlap. */
|
||
if (TREE_CODE (typex) == RECORD_TYPE
|
||
&& fieldx != fieldy)
|
||
return true;
|
||
|
||
/* The comparison on the current field failed. If we're accessing
|
||
a very nested structure, look at the next outer level. */
|
||
x = TREE_OPERAND (x, 0);
|
||
y = TREE_OPERAND (y, 0);
|
||
}
|
||
while (x && y
|
||
&& TREE_CODE (x) == COMPONENT_REF
|
||
&& TREE_CODE (y) == COMPONENT_REF);
|
||
|
||
return false;
|
||
}
|
||
|
||
/* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */
|
||
|
||
static tree
|
||
decl_for_component_ref (x)
|
||
tree x;
|
||
{
|
||
do
|
||
{
|
||
x = TREE_OPERAND (x, 0);
|
||
}
|
||
while (x && TREE_CODE (x) == COMPONENT_REF);
|
||
|
||
return x && DECL_P (x) ? x : NULL_TREE;
|
||
}
|
||
|
||
/* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the
|
||
offset of the field reference. */
|
||
|
||
static rtx
|
||
adjust_offset_for_component_ref (x, offset)
|
||
tree x;
|
||
rtx offset;
|
||
{
|
||
HOST_WIDE_INT ioffset;
|
||
|
||
if (! offset)
|
||
return NULL_RTX;
|
||
|
||
ioffset = INTVAL (offset);
|
||
do
|
||
{
|
||
tree field = TREE_OPERAND (x, 1);
|
||
|
||
if (! host_integerp (DECL_FIELD_OFFSET (field), 1))
|
||
return NULL_RTX;
|
||
ioffset += (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
|
||
+ (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
|
||
/ BITS_PER_UNIT));
|
||
|
||
x = TREE_OPERAND (x, 0);
|
||
}
|
||
while (x && TREE_CODE (x) == COMPONENT_REF);
|
||
|
||
return GEN_INT (ioffset);
|
||
}
|
||
|
||
/* Return nonzero if we can deterimine the exprs corresponding to memrefs
|
||
X and Y and they do not overlap. */
|
||
|
||
static int
|
||
nonoverlapping_memrefs_p (x, y)
|
||
rtx x, y;
|
||
{
|
||
tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y);
|
||
rtx rtlx, rtly;
|
||
rtx basex, basey;
|
||
rtx moffsetx, moffsety;
|
||
HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem;
|
||
|
||
/* Unless both have exprs, we can't tell anything. */
|
||
if (exprx == 0 || expry == 0)
|
||
return 0;
|
||
|
||
/* If both are field references, we may be able to determine something. */
|
||
if (TREE_CODE (exprx) == COMPONENT_REF
|
||
&& TREE_CODE (expry) == COMPONENT_REF
|
||
&& nonoverlapping_component_refs_p (exprx, expry))
|
||
return 1;
|
||
|
||
/* If the field reference test failed, look at the DECLs involved. */
|
||
moffsetx = MEM_OFFSET (x);
|
||
if (TREE_CODE (exprx) == COMPONENT_REF)
|
||
{
|
||
tree t = decl_for_component_ref (exprx);
|
||
if (! t)
|
||
return 0;
|
||
moffsetx = adjust_offset_for_component_ref (exprx, moffsetx);
|
||
exprx = t;
|
||
}
|
||
moffsety = MEM_OFFSET (y);
|
||
if (TREE_CODE (expry) == COMPONENT_REF)
|
||
{
|
||
tree t = decl_for_component_ref (expry);
|
||
if (! t)
|
||
return 0;
|
||
moffsety = adjust_offset_for_component_ref (expry, moffsety);
|
||
expry = t;
|
||
}
|
||
|
||
if (! DECL_P (exprx) || ! DECL_P (expry))
|
||
return 0;
|
||
|
||
rtlx = DECL_RTL (exprx);
|
||
rtly = DECL_RTL (expry);
|
||
|
||
/* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they
|
||
can't overlap unless they are the same because we never reuse that part
|
||
of the stack frame used for locals for spilled pseudos. */
|
||
if ((GET_CODE (rtlx) != MEM || GET_CODE (rtly) != MEM)
|
||
&& ! rtx_equal_p (rtlx, rtly))
|
||
return 1;
|
||
|
||
/* Get the base and offsets of both decls. If either is a register, we
|
||
know both are and are the same, so use that as the base. The only
|
||
we can avoid overlap is if we can deduce that they are nonoverlapping
|
||
pieces of that decl, which is very rare. */
|
||
basex = GET_CODE (rtlx) == MEM ? XEXP (rtlx, 0) : rtlx;
|
||
if (GET_CODE (basex) == PLUS && GET_CODE (XEXP (basex, 1)) == CONST_INT)
|
||
offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0);
|
||
|
||
basey = GET_CODE (rtly) == MEM ? XEXP (rtly, 0) : rtly;
|
||
if (GET_CODE (basey) == PLUS && GET_CODE (XEXP (basey, 1)) == CONST_INT)
|
||
offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0);
|
||
|
||
/* If the bases are different, we know they do not overlap if both
|
||
are constants or if one is a constant and the other a pointer into the
|
||
stack frame. Otherwise a different base means we can't tell if they
|
||
overlap or not. */
|
||
if (! rtx_equal_p (basex, basey))
|
||
return ((CONSTANT_P (basex) && CONSTANT_P (basey))
|
||
|| (CONSTANT_P (basex) && REG_P (basey)
|
||
&& REGNO_PTR_FRAME_P (REGNO (basey)))
|
||
|| (CONSTANT_P (basey) && REG_P (basex)
|
||
&& REGNO_PTR_FRAME_P (REGNO (basex))));
|
||
|
||
sizex = (GET_CODE (rtlx) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtlx))
|
||
: MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx))
|
||
: -1);
|
||
sizey = (GET_CODE (rtly) != MEM ? (int) GET_MODE_SIZE (GET_MODE (rtly))
|
||
: MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) :
|
||
-1);
|
||
|
||
/* If we have an offset for either memref, it can update the values computed
|
||
above. */
|
||
if (moffsetx)
|
||
offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx);
|
||
if (moffsety)
|
||
offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety);
|
||
|
||
/* If a memref has both a size and an offset, we can use the smaller size.
|
||
We can't do this if the offset isn't known because we must view this
|
||
memref as being anywhere inside the DECL's MEM. */
|
||
if (MEM_SIZE (x) && moffsetx)
|
||
sizex = INTVAL (MEM_SIZE (x));
|
||
if (MEM_SIZE (y) && moffsety)
|
||
sizey = INTVAL (MEM_SIZE (y));
|
||
|
||
/* Put the values of the memref with the lower offset in X's values. */
|
||
if (offsetx > offsety)
|
||
{
|
||
tem = offsetx, offsetx = offsety, offsety = tem;
|
||
tem = sizex, sizex = sizey, sizey = tem;
|
||
}
|
||
|
||
/* If we don't know the size of the lower-offset value, we can't tell
|
||
if they conflict. Otherwise, we do the test. */
|
||
return sizex >= 0 && offsety > offsetx + sizex;
|
||
}
|
||
|
||
/* True dependence: X is read after store in MEM takes place. */
|
||
|
||
int
|
||
true_dependence (mem, mem_mode, x, varies)
|
||
rtx mem;
|
||
enum machine_mode mem_mode;
|
||
rtx x;
|
||
int (*varies) PARAMS ((rtx, int));
|
||
{
|
||
rtx x_addr, mem_addr;
|
||
rtx base;
|
||
|
||
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
|
||
return 1;
|
||
|
||
if (DIFFERENT_ALIAS_SETS_P (x, mem))
|
||
return 0;
|
||
|
||
/* Unchanging memory can't conflict with non-unchanging memory.
|
||
A non-unchanging read can conflict with a non-unchanging write.
|
||
An unchanging read can conflict with an unchanging write since
|
||
there may be a single store to this address to initialize it.
|
||
Note that an unchanging store can conflict with a non-unchanging read
|
||
since we have to make conservative assumptions when we have a
|
||
record with readonly fields and we are copying the whole thing.
|
||
Just fall through to the code below to resolve potential conflicts.
|
||
This won't handle all cases optimally, but the possible performance
|
||
loss should be negligible. */
|
||
if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem))
|
||
return 0;
|
||
|
||
if (nonoverlapping_memrefs_p (mem, x))
|
||
return 0;
|
||
|
||
if (mem_mode == VOIDmode)
|
||
mem_mode = GET_MODE (mem);
|
||
|
||
x_addr = get_addr (XEXP (x, 0));
|
||
mem_addr = get_addr (XEXP (mem, 0));
|
||
|
||
base = find_base_term (x_addr);
|
||
if (base && (GET_CODE (base) == LABEL_REF
|
||
|| (GET_CODE (base) == SYMBOL_REF
|
||
&& CONSTANT_POOL_ADDRESS_P (base))))
|
||
return 0;
|
||
|
||
if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
|
||
return 0;
|
||
|
||
x_addr = canon_rtx (x_addr);
|
||
mem_addr = canon_rtx (mem_addr);
|
||
|
||
if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
|
||
SIZE_FOR_MODE (x), x_addr, 0))
|
||
return 0;
|
||
|
||
if (aliases_everything_p (x))
|
||
return 1;
|
||
|
||
/* We cannot use aliases_everything_p to test MEM, since we must look
|
||
at MEM_MODE, rather than GET_MODE (MEM). */
|
||
if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
|
||
return 1;
|
||
|
||
/* In true_dependence we also allow BLKmode to alias anything. Why
|
||
don't we do this in anti_dependence and output_dependence? */
|
||
if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
|
||
return 1;
|
||
|
||
return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
|
||
varies);
|
||
}
|
||
|
||
/* Canonical true dependence: X is read after store in MEM takes place.
|
||
Variant of true_dependence which assumes MEM has already been
|
||
canonicalized (hence we no longer do that here).
|
||
The mem_addr argument has been added, since true_dependence computed
|
||
this value prior to canonicalizing. */
|
||
|
||
int
|
||
canon_true_dependence (mem, mem_mode, mem_addr, x, varies)
|
||
rtx mem, mem_addr, x;
|
||
enum machine_mode mem_mode;
|
||
int (*varies) PARAMS ((rtx, int));
|
||
{
|
||
rtx x_addr;
|
||
|
||
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
|
||
return 1;
|
||
|
||
if (DIFFERENT_ALIAS_SETS_P (x, mem))
|
||
return 0;
|
||
|
||
/* If X is an unchanging read, then it can't possibly conflict with any
|
||
non-unchanging store. It may conflict with an unchanging write though,
|
||
because there may be a single store to this address to initialize it.
|
||
Just fall through to the code below to resolve the case where we have
|
||
both an unchanging read and an unchanging write. This won't handle all
|
||
cases optimally, but the possible performance loss should be
|
||
negligible. */
|
||
if (RTX_UNCHANGING_P (x) && ! RTX_UNCHANGING_P (mem))
|
||
return 0;
|
||
|
||
if (nonoverlapping_memrefs_p (x, mem))
|
||
return 0;
|
||
|
||
x_addr = get_addr (XEXP (x, 0));
|
||
|
||
if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
|
||
return 0;
|
||
|
||
x_addr = canon_rtx (x_addr);
|
||
if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
|
||
SIZE_FOR_MODE (x), x_addr, 0))
|
||
return 0;
|
||
|
||
if (aliases_everything_p (x))
|
||
return 1;
|
||
|
||
/* We cannot use aliases_everything_p to test MEM, since we must look
|
||
at MEM_MODE, rather than GET_MODE (MEM). */
|
||
if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
|
||
return 1;
|
||
|
||
/* In true_dependence we also allow BLKmode to alias anything. Why
|
||
don't we do this in anti_dependence and output_dependence? */
|
||
if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
|
||
return 1;
|
||
|
||
return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
|
||
varies);
|
||
}
|
||
|
||
/* Returns non-zero if a write to X might alias a previous read from
|
||
(or, if WRITEP is non-zero, a write to) MEM. */
|
||
|
||
static int
|
||
write_dependence_p (mem, x, writep)
|
||
rtx mem;
|
||
rtx x;
|
||
int writep;
|
||
{
|
||
rtx x_addr, mem_addr;
|
||
rtx fixed_scalar;
|
||
rtx base;
|
||
|
||
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
|
||
return 1;
|
||
|
||
if (DIFFERENT_ALIAS_SETS_P (x, mem))
|
||
return 0;
|
||
|
||
/* Unchanging memory can't conflict with non-unchanging memory. */
|
||
if (RTX_UNCHANGING_P (x) != RTX_UNCHANGING_P (mem))
|
||
return 0;
|
||
|
||
/* If MEM is an unchanging read, then it can't possibly conflict with
|
||
the store to X, because there is at most one store to MEM, and it must
|
||
have occurred somewhere before MEM. */
|
||
if (! writep && RTX_UNCHANGING_P (mem))
|
||
return 0;
|
||
|
||
if (nonoverlapping_memrefs_p (x, mem))
|
||
return 0;
|
||
|
||
x_addr = get_addr (XEXP (x, 0));
|
||
mem_addr = get_addr (XEXP (mem, 0));
|
||
|
||
if (! writep)
|
||
{
|
||
base = find_base_term (mem_addr);
|
||
if (base && (GET_CODE (base) == LABEL_REF
|
||
|| (GET_CODE (base) == SYMBOL_REF
|
||
&& CONSTANT_POOL_ADDRESS_P (base))))
|
||
return 0;
|
||
}
|
||
|
||
if (! base_alias_check (x_addr, mem_addr, GET_MODE (x),
|
||
GET_MODE (mem)))
|
||
return 0;
|
||
|
||
x_addr = canon_rtx (x_addr);
|
||
mem_addr = canon_rtx (mem_addr);
|
||
|
||
if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
|
||
SIZE_FOR_MODE (x), x_addr, 0))
|
||
return 0;
|
||
|
||
fixed_scalar
|
||
= fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
|
||
rtx_addr_varies_p);
|
||
|
||
return (!(fixed_scalar == mem && !aliases_everything_p (x))
|
||
&& !(fixed_scalar == x && !aliases_everything_p (mem)));
|
||
}
|
||
|
||
/* Anti dependence: X is written after read in MEM takes place. */
|
||
|
||
int
|
||
anti_dependence (mem, x)
|
||
rtx mem;
|
||
rtx x;
|
||
{
|
||
return write_dependence_p (mem, x, /*writep=*/0);
|
||
}
|
||
|
||
/* Output dependence: X is written after store in MEM takes place. */
|
||
|
||
int
|
||
output_dependence (mem, x)
|
||
rtx mem;
|
||
rtx x;
|
||
{
|
||
return write_dependence_p (mem, x, /*writep=*/1);
|
||
}
|
||
|
||
/* Returns non-zero if X mentions something which is not
|
||
local to the function and is not constant. */
|
||
|
||
static int
|
||
nonlocal_mentioned_p (x)
|
||
rtx x;
|
||
{
|
||
rtx base;
|
||
RTX_CODE code;
|
||
int regno;
|
||
|
||
code = GET_CODE (x);
|
||
|
||
if (GET_RTX_CLASS (code) == 'i')
|
||
{
|
||
/* Constant functions can be constant if they don't use
|
||
scratch memory used to mark function w/o side effects. */
|
||
if (code == CALL_INSN && CONST_OR_PURE_CALL_P (x))
|
||
{
|
||
x = CALL_INSN_FUNCTION_USAGE (x);
|
||
if (x == 0)
|
||
return 0;
|
||
}
|
||
else
|
||
x = PATTERN (x);
|
||
code = GET_CODE (x);
|
||
}
|
||
|
||
switch (code)
|
||
{
|
||
case SUBREG:
|
||
if (GET_CODE (SUBREG_REG (x)) == REG)
|
||
{
|
||
/* Global registers are not local. */
|
||
if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER
|
||
&& global_regs[subreg_regno (x)])
|
||
return 1;
|
||
return 0;
|
||
}
|
||
break;
|
||
|
||
case REG:
|
||
regno = REGNO (x);
|
||
/* Global registers are not local. */
|
||
if (regno < FIRST_PSEUDO_REGISTER && global_regs[regno])
|
||
return 1;
|
||
return 0;
|
||
|
||
case SCRATCH:
|
||
case PC:
|
||
case CC0:
|
||
case CONST_INT:
|
||
case CONST_DOUBLE:
|
||
case CONST_VECTOR:
|
||
case CONST:
|
||
case LABEL_REF:
|
||
return 0;
|
||
|
||
case SYMBOL_REF:
|
||
/* Constants in the function's constants pool are constant. */
|
||
if (CONSTANT_POOL_ADDRESS_P (x))
|
||
return 0;
|
||
return 1;
|
||
|
||
case CALL:
|
||
/* Non-constant calls and recursion are not local. */
|
||
return 1;
|
||
|
||
case MEM:
|
||
/* Be overly conservative and consider any volatile memory
|
||
reference as not local. */
|
||
if (MEM_VOLATILE_P (x))
|
||
return 1;
|
||
base = find_base_term (XEXP (x, 0));
|
||
if (base)
|
||
{
|
||
/* A Pmode ADDRESS could be a reference via the structure value
|
||
address or static chain. Such memory references are nonlocal.
|
||
|
||
Thus, we have to examine the contents of the ADDRESS to find
|
||
out if this is a local reference or not. */
|
||
if (GET_CODE (base) == ADDRESS
|
||
&& GET_MODE (base) == Pmode
|
||
&& (XEXP (base, 0) == stack_pointer_rtx
|
||
|| XEXP (base, 0) == arg_pointer_rtx
|
||
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
|
||
|| XEXP (base, 0) == hard_frame_pointer_rtx
|
||
#endif
|
||
|| XEXP (base, 0) == frame_pointer_rtx))
|
||
return 0;
|
||
/* Constants in the function's constant pool are constant. */
|
||
if (GET_CODE (base) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (base))
|
||
return 0;
|
||
}
|
||
return 1;
|
||
|
||
case UNSPEC_VOLATILE:
|
||
case ASM_INPUT:
|
||
return 1;
|
||
|
||
case ASM_OPERANDS:
|
||
if (MEM_VOLATILE_P (x))
|
||
return 1;
|
||
|
||
/* FALLTHROUGH */
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* Recursively scan the operands of this expression. */
|
||
|
||
{
|
||
const char *fmt = GET_RTX_FORMAT (code);
|
||
int i;
|
||
|
||
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
|
||
{
|
||
if (fmt[i] == 'e' && XEXP (x, i))
|
||
{
|
||
if (nonlocal_mentioned_p (XEXP (x, i)))
|
||
return 1;
|
||
}
|
||
else if (fmt[i] == 'E')
|
||
{
|
||
int j;
|
||
for (j = 0; j < XVECLEN (x, i); j++)
|
||
if (nonlocal_mentioned_p (XVECEXP (x, i, j)))
|
||
return 1;
|
||
}
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Mark the function if it is constant. */
|
||
|
||
void
|
||
mark_constant_function ()
|
||
{
|
||
rtx insn;
|
||
int nonlocal_mentioned;
|
||
|
||
if (TREE_PUBLIC (current_function_decl)
|
||
|| TREE_READONLY (current_function_decl)
|
||
|| DECL_IS_PURE (current_function_decl)
|
||
|| TREE_THIS_VOLATILE (current_function_decl)
|
||
|| TYPE_MODE (TREE_TYPE (current_function_decl)) == VOIDmode)
|
||
return;
|
||
|
||
/* A loop might not return which counts as a side effect. */
|
||
if (mark_dfs_back_edges ())
|
||
return;
|
||
|
||
nonlocal_mentioned = 0;
|
||
|
||
init_alias_analysis ();
|
||
|
||
/* Determine if this is a constant function. */
|
||
|
||
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
|
||
if (INSN_P (insn) && nonlocal_mentioned_p (insn))
|
||
{
|
||
nonlocal_mentioned = 1;
|
||
break;
|
||
}
|
||
|
||
end_alias_analysis ();
|
||
|
||
/* Mark the function. */
|
||
|
||
if (! nonlocal_mentioned)
|
||
TREE_READONLY (current_function_decl) = 1;
|
||
}
|
||
|
||
|
||
static HARD_REG_SET argument_registers;
|
||
|
||
void
|
||
init_alias_once ()
|
||
{
|
||
int i;
|
||
|
||
#ifndef OUTGOING_REGNO
|
||
#define OUTGOING_REGNO(N) N
|
||
#endif
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
/* Check whether this register can hold an incoming pointer
|
||
argument. FUNCTION_ARG_REGNO_P tests outgoing register
|
||
numbers, so translate if necessary due to register windows. */
|
||
if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i))
|
||
&& HARD_REGNO_MODE_OK (i, Pmode))
|
||
SET_HARD_REG_BIT (argument_registers, i);
|
||
|
||
alias_sets = splay_tree_new (splay_tree_compare_ints, 0, 0);
|
||
}
|
||
|
||
/* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE
|
||
array. */
|
||
|
||
void
|
||
init_alias_analysis ()
|
||
{
|
||
int maxreg = max_reg_num ();
|
||
int changed, pass;
|
||
int i;
|
||
unsigned int ui;
|
||
rtx insn;
|
||
|
||
reg_known_value_size = maxreg;
|
||
|
||
reg_known_value
|
||
= (rtx *) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (rtx))
|
||
- FIRST_PSEUDO_REGISTER;
|
||
reg_known_equiv_p
|
||
= (char*) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (char))
|
||
- FIRST_PSEUDO_REGISTER;
|
||
|
||
/* Overallocate reg_base_value to allow some growth during loop
|
||
optimization. Loop unrolling can create a large number of
|
||
registers. */
|
||
reg_base_value_size = maxreg * 2;
|
||
reg_base_value = (rtx *) xcalloc (reg_base_value_size, sizeof (rtx));
|
||
ggc_add_rtx_root (reg_base_value, reg_base_value_size);
|
||
|
||
new_reg_base_value = (rtx *) xmalloc (reg_base_value_size * sizeof (rtx));
|
||
reg_seen = (char *) xmalloc (reg_base_value_size);
|
||
if (! reload_completed && flag_unroll_loops)
|
||
{
|
||
/* ??? Why are we realloc'ing if we're just going to zero it? */
|
||
alias_invariant = (rtx *)xrealloc (alias_invariant,
|
||
reg_base_value_size * sizeof (rtx));
|
||
memset ((char *)alias_invariant, 0, reg_base_value_size * sizeof (rtx));
|
||
}
|
||
|
||
/* The basic idea is that each pass through this loop will use the
|
||
"constant" information from the previous pass to propagate alias
|
||
information through another level of assignments.
|
||
|
||
This could get expensive if the assignment chains are long. Maybe
|
||
we should throttle the number of iterations, possibly based on
|
||
the optimization level or flag_expensive_optimizations.
|
||
|
||
We could propagate more information in the first pass by making use
|
||
of REG_N_SETS to determine immediately that the alias information
|
||
for a pseudo is "constant".
|
||
|
||
A program with an uninitialized variable can cause an infinite loop
|
||
here. Instead of doing a full dataflow analysis to detect such problems
|
||
we just cap the number of iterations for the loop.
|
||
|
||
The state of the arrays for the set chain in question does not matter
|
||
since the program has undefined behavior. */
|
||
|
||
pass = 0;
|
||
do
|
||
{
|
||
/* Assume nothing will change this iteration of the loop. */
|
||
changed = 0;
|
||
|
||
/* We want to assign the same IDs each iteration of this loop, so
|
||
start counting from zero each iteration of the loop. */
|
||
unique_id = 0;
|
||
|
||
/* We're at the start of the function each iteration through the
|
||
loop, so we're copying arguments. */
|
||
copying_arguments = 1;
|
||
|
||
/* Wipe the potential alias information clean for this pass. */
|
||
memset ((char *) new_reg_base_value, 0, reg_base_value_size * sizeof (rtx));
|
||
|
||
/* Wipe the reg_seen array clean. */
|
||
memset ((char *) reg_seen, 0, reg_base_value_size);
|
||
|
||
/* Mark all hard registers which may contain an address.
|
||
The stack, frame and argument pointers may contain an address.
|
||
An argument register which can hold a Pmode value may contain
|
||
an address even if it is not in BASE_REGS.
|
||
|
||
The address expression is VOIDmode for an argument and
|
||
Pmode for other registers. */
|
||
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
if (TEST_HARD_REG_BIT (argument_registers, i))
|
||
new_reg_base_value[i] = gen_rtx_ADDRESS (VOIDmode,
|
||
gen_rtx_REG (Pmode, i));
|
||
|
||
new_reg_base_value[STACK_POINTER_REGNUM]
|
||
= gen_rtx_ADDRESS (Pmode, stack_pointer_rtx);
|
||
new_reg_base_value[ARG_POINTER_REGNUM]
|
||
= gen_rtx_ADDRESS (Pmode, arg_pointer_rtx);
|
||
new_reg_base_value[FRAME_POINTER_REGNUM]
|
||
= gen_rtx_ADDRESS (Pmode, frame_pointer_rtx);
|
||
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
|
||
new_reg_base_value[HARD_FRAME_POINTER_REGNUM]
|
||
= gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx);
|
||
#endif
|
||
|
||
/* Walk the insns adding values to the new_reg_base_value array. */
|
||
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
|
||
{
|
||
if (INSN_P (insn))
|
||
{
|
||
rtx note, set;
|
||
|
||
#if defined (HAVE_prologue) || defined (HAVE_epilogue)
|
||
/* The prologue/epilogue insns are not threaded onto the
|
||
insn chain until after reload has completed. Thus,
|
||
there is no sense wasting time checking if INSN is in
|
||
the prologue/epilogue until after reload has completed. */
|
||
if (reload_completed
|
||
&& prologue_epilogue_contains (insn))
|
||
continue;
|
||
#endif
|
||
|
||
/* If this insn has a noalias note, process it, Otherwise,
|
||
scan for sets. A simple set will have no side effects
|
||
which could change the base value of any other register. */
|
||
|
||
if (GET_CODE (PATTERN (insn)) == SET
|
||
&& REG_NOTES (insn) != 0
|
||
&& 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);
|
||
|
||
set = single_set (insn);
|
||
|
||
if (set != 0
|
||
&& GET_CODE (SET_DEST (set)) == REG
|
||
&& REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER)
|
||
{
|
||
unsigned int regno = REGNO (SET_DEST (set));
|
||
rtx src = SET_SRC (set);
|
||
|
||
if (REG_NOTES (insn) != 0
|
||
&& (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0
|
||
&& REG_N_SETS (regno) == 1)
|
||
|| (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0)
|
||
&& GET_CODE (XEXP (note, 0)) != EXPR_LIST
|
||
&& ! rtx_varies_p (XEXP (note, 0), 1)
|
||
&& ! reg_overlap_mentioned_p (SET_DEST (set), XEXP (note, 0)))
|
||
{
|
||
reg_known_value[regno] = XEXP (note, 0);
|
||
reg_known_equiv_p[regno] = REG_NOTE_KIND (note) == REG_EQUIV;
|
||
}
|
||
else if (REG_N_SETS (regno) == 1
|
||
&& GET_CODE (src) == PLUS
|
||
&& GET_CODE (XEXP (src, 0)) == REG
|
||
&& REGNO (XEXP (src, 0)) >= FIRST_PSEUDO_REGISTER
|
||
&& (reg_known_value[REGNO (XEXP (src, 0))])
|
||
&& GET_CODE (XEXP (src, 1)) == CONST_INT)
|
||
{
|
||
rtx op0 = XEXP (src, 0);
|
||
op0 = reg_known_value[REGNO (op0)];
|
||
reg_known_value[regno]
|
||
= plus_constant (op0, INTVAL (XEXP (src, 1)));
|
||
reg_known_equiv_p[regno] = 0;
|
||
}
|
||
else if (REG_N_SETS (regno) == 1
|
||
&& ! rtx_varies_p (src, 1))
|
||
{
|
||
reg_known_value[regno] = src;
|
||
reg_known_equiv_p[regno] = 0;
|
||
}
|
||
}
|
||
}
|
||
else if (GET_CODE (insn) == NOTE
|
||
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
|
||
copying_arguments = 0;
|
||
}
|
||
|
||
/* Now propagate values from new_reg_base_value to reg_base_value. */
|
||
for (ui = 0; ui < reg_base_value_size; ui++)
|
||
{
|
||
if (new_reg_base_value[ui]
|
||
&& new_reg_base_value[ui] != reg_base_value[ui]
|
||
&& ! rtx_equal_p (new_reg_base_value[ui], reg_base_value[ui]))
|
||
{
|
||
reg_base_value[ui] = new_reg_base_value[ui];
|
||
changed = 1;
|
||
}
|
||
}
|
||
}
|
||
while (changed && ++pass < MAX_ALIAS_LOOP_PASSES);
|
||
|
||
/* Fill in the remaining entries. */
|
||
for (i = FIRST_PSEUDO_REGISTER; i < maxreg; i++)
|
||
if (reg_known_value[i] == 0)
|
||
reg_known_value[i] = regno_reg_rtx[i];
|
||
|
||
/* Simplify the reg_base_value array so that no register refers to
|
||
another register, except to special registers indirectly through
|
||
ADDRESS expressions.
|
||
|
||
In theory this loop can take as long as O(registers^2), but unless
|
||
there are very long dependency chains it will run in close to linear
|
||
time.
|
||
|
||
This loop may not be needed any longer now that the main loop does
|
||
a better job at propagating alias information. */
|
||
pass = 0;
|
||
do
|
||
{
|
||
changed = 0;
|
||
pass++;
|
||
for (ui = 0; ui < reg_base_value_size; ui++)
|
||
{
|
||
rtx base = reg_base_value[ui];
|
||
if (base && GET_CODE (base) == REG)
|
||
{
|
||
unsigned int base_regno = REGNO (base);
|
||
if (base_regno == ui) /* register set from itself */
|
||
reg_base_value[ui] = 0;
|
||
else
|
||
reg_base_value[ui] = reg_base_value[base_regno];
|
||
changed = 1;
|
||
}
|
||
}
|
||
}
|
||
while (changed && pass < MAX_ALIAS_LOOP_PASSES);
|
||
|
||
/* Clean up. */
|
||
free (new_reg_base_value);
|
||
new_reg_base_value = 0;
|
||
free (reg_seen);
|
||
reg_seen = 0;
|
||
}
|
||
|
||
void
|
||
end_alias_analysis ()
|
||
{
|
||
free (reg_known_value + FIRST_PSEUDO_REGISTER);
|
||
reg_known_value = 0;
|
||
reg_known_value_size = 0;
|
||
free (reg_known_equiv_p + FIRST_PSEUDO_REGISTER);
|
||
reg_known_equiv_p = 0;
|
||
if (reg_base_value)
|
||
{
|
||
ggc_del_root (reg_base_value);
|
||
free (reg_base_value);
|
||
reg_base_value = 0;
|
||
}
|
||
reg_base_value_size = 0;
|
||
if (alias_invariant)
|
||
{
|
||
free (alias_invariant);
|
||
alias_invariant = 0;
|
||
}
|
||
}
|