/* Alias analysis for GNU C
- Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
+ Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
Contributed by John Carr (jfc@mit.edu).
-This file is part of GNU CC.
+This file is part of GCC.
-GNU CC 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 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.
-GNU CC 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.
+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 GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+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 "tree.h"
#include "tm_p.h"
#include "function.h"
-#include "insn-flags.h"
#include "expr.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "cselib.h"
#include "splay-tree.h"
#include "ggc.h"
+#include "langhooks.h"
+#include "target.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
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 decendents, however, since we propagate all
+ past immediate descendents, however, since we propagate all
grandchildren up one level.
Alias set zero is implicitly a superset of all other alias sets.
HOST_WIDE_INT alias_set;
/* The children of the alias set. These are not just the immediate
- children, but, in fact, all decendents. So, if we have:
+ children, but, in fact, all descendents. So, if we have:
- struct T { struct S s; float f; }
+ struct T { struct S s; float f; }
continuing our example above, the children here will be all of
`int', `double', `float', and `struct S'. */
static int rtx_equal_for_memref_p PARAMS ((rtx, rtx));
static rtx find_symbolic_term PARAMS ((rtx));
-static rtx get_addr 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_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 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));
-static int loop_p PARAMS ((void));
+static int nonlocal_mentioned_p_1 PARAMS ((rtx *, void *));
+static int nonlocal_mentioned_p PARAMS ((rtx));
+static int nonlocal_referenced_p_1 PARAMS ((rtx *, void *));
+static int nonlocal_referenced_p PARAMS ((rtx));
+static int nonlocal_set_p_1 PARAMS ((rtx *, void *));
+static int nonlocal_set_p PARAMS ((rtx));
/* Set up all info needed to perform alias analysis on memory references. */
/* 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
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 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
current function performs nonlocal memory memory references for the
purposes of marking the function as a constant function. */
-static rtx *reg_base_value;
+static GTY((length ("reg_base_value_size"))) rtx *reg_base_value;
static rtx *new_reg_base_value;
static unsigned int reg_base_value_size; /* size of reg_base_value array */
+/* Static hunks of RTL used by the aliasing code; these are initialized
+ once per function to avoid unnecessary RTL allocations. */
+static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER];
+
#define REG_BASE_VALUE(X) \
- (REGNO (X) < reg_base_value_size ? reg_base_value[REGNO (X)] : 0)
+ (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
/* Returns nonzero if the alias sets for MEM1 and MEM2 are such that
the two MEMs cannot alias each other. */
-static int
+static int
mems_in_disjoint_alias_sets_p (mem1, mem2)
rtx mem1;
rtx mem2;
{
-#ifdef ENABLE_CHECKING
+#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
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;
- /* We now know they are different types. If one or both has readonly fields
- or if one is readonly and the other not, they may not conflict.
- Likewise if one is aggregate and the other is scalar. */
- if ((t1 != 0 && readonly_fields_p (t1))
- || (t2 != 0 && readonly_fields_p (t2))
- || ((t1 != 0 && TYPE_READONLY (t1))
- != (t2 != 0 && TYPE_READONLY (t2)))
- || ((t1 != 0 && AGGREGATE_TYPE_P (t1))
- != (t2 != 0 && AGGREGATE_TYPE_P (t2))))
+ /* 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. */
+ /* 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 retured. */
+ NULL_TREE is returned. */
static tree
find_base_decl (t)
case '3':
d0 = find_base_decl (TREE_OPERAND (t, 0));
d1 = find_base_decl (TREE_OPERAND (t, 1));
- d0 = find_base_decl (TREE_OPERAND (t, 0));
d2 = find_base_decl (TREE_OPERAND (t, 2));
/* Set any nonzero values from the last, then from the first. */
}
}
+/* 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. */
get_alias_set (t)
tree t;
{
- tree orig_t;
HOST_WIDE_INT set;
/* If we're not doing any alias analysis, just assume everything
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 and start by removing nops
- since we care only about the actual object. */
+ 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))
{
- while (TREE_CODE (t) == NOP_EXPR || TREE_CODE (t) == CONVERT_EXPR
- || TREE_CODE (t) == NON_LVALUE_EXPR)
- t = TREE_OPERAND (t, 0);
-
- /* Now give the language a chance to do something but record what we
- gave it this time. */
- orig_t = t;
- if ((set = lang_get_alias_set (t)) != -1)
+ 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;
- /* Now loop the same way as get_inner_reference and get the alias
- set to use. Pick up the outermost object that we could have
- a pointer to. */
- while (1)
+ /* 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))
{
- /* Unnamed bitfields are not an addressable object. */
- if (TREE_CODE (t) == BIT_FIELD_REF)
- ;
- else if (TREE_CODE (t) == COMPONENT_REF)
- {
- if (! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
- /* Stop at an adressable decl. */
- break;
- }
- else if (TREE_CODE (t) == ARRAY_REF)
- {
- if (! TYPE_NONALIASED_COMPONENT
- (TREE_TYPE (TREE_OPERAND (t, 0))))
- /* Stop at an addresssable array element. */
- break;
- }
- else if (TREE_CODE (t) != NON_LVALUE_EXPR
- && ! ((TREE_CODE (t) == NOP_EXPR
- || TREE_CODE (t) == CONVERT_EXPR)
- && (TYPE_MODE (TREE_TYPE (t))
- == TYPE_MODE (TREE_TYPE (TREE_OPERAND (t, 0))))))
- /* Stop if not one of above and not mode-preserving conversion. */
- break;
-
- t = TREE_OPERAND (t, 0);
+ if (TREE_CODE (inner) == PLACEHOLDER_EXPR)
+ inner = find_placeholder (inner, &placeholder_ptr);
+ else
+ inner = TREE_OPERAND (inner, 0);
+
+ STRIP_NOPS (inner);
}
-
- if (TREE_CODE (t) == INDIRECT_REF)
+
+ /* Check for accesses through restrict-qualified pointers. */
+ if (TREE_CODE (inner) == INDIRECT_REF)
{
- /* Check for accesses through restrict-qualified pointers. */
- tree decl = find_base_decl (TREE_OPERAND (t, 0));
+ tree decl = find_base_decl (TREE_OPERAND (inner, 0));
if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl))
- /* We use the alias set indicated in the declaration. */
- return DECL_POINTER_ALIAS_SET (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. */
- if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE)
+ else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE)
return 0;
}
- /* Give the language another chance to do something special. */
- if (orig_t != t
- && (set = lang_get_alias_set (t)) != -1)
- return set;
+ /* 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_P (t) && TYPE_ALIAS_SET_KNOWN_P (t))
+ if (TYPE_ALIAS_SET_KNOWN_P (t))
return TYPE_ALIAS_SET (t);
/* See if the language has special handling for this type. */
- if ((set = lang_get_alias_set (t)) != -1)
- {
- /* If the alias set is now known, we are done. */
- if (TYPE_ALIAS_SET_KNOWN_P (t))
- return TYPE_ALIAS_SET (t);
- }
+ 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;
+
+ /* Unless the language specifies otherwise, let vector types alias
+ their components. This avoids some nasty type punning issues in
+ normal usage. And indeed lets vectors be treated more like an
+ array slice. */
+ else if (TREE_CODE (t) == VECTOR_TYPE)
+ set = get_alias_set (TREE_TYPE (t));
+
else
/* Otherwise make a new alias set for this type. */
set = new_alias_set ();
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.
+ 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. */
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)
+ 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
+ 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,
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)
{
if (subset_entry->has_zero_child)
superset_entry->has_zero_child = 1;
}
/* Enter the SUBSET itself as a child of the SUPERSET. */
- splay_tree_insert (superset_entry->children,
+ splay_tree_insert (superset_entry->children,
(splay_tree_key) subset, 0);
}
}
case RECORD_TYPE:
case UNION_TYPE:
case QUAL_UNION_TYPE:
+ /* Recursively record aliases for the base classes, if there are any */
+ if (TYPE_BINFO (type) != NULL && TYPE_BINFO_BASETYPES (type) != NULL)
+ {
+ int i;
+ for (i = 0; i < TREE_VEC_LENGTH (TYPE_BINFO_BASETYPES (type)); i++)
+ {
+ tree binfo = TREE_VEC_ELT (TYPE_BINFO_BASETYPES (type), i);
+ record_alias_subset (superset,
+ get_alias_set (BINFO_TYPE (binfo)));
+ }
+ }
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)));
static rtx
find_base_value (src)
- register rtx src;
+ rtx src;
{
+ unsigned int regno;
+
switch (GET_CODE (src))
{
case SYMBOL_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 (src) < FIRST_PSEUDO_REGISTER && copying_arguments)
- return new_reg_base_value[REGNO (src)];
+ 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 hard regs since it can result in a circular dependency
- chain for registers which have values at function entry.
+ 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 (src) >= FIRST_PSEUDO_REGISTER
- && (unsigned) REGNO (src) < reg_base_value_size
- && reg_base_value[REGNO (src)])
- return reg_base_value[REGNO (src)];
+ if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno])
+ && regno < reg_base_value_size
+ && reg_base_value[regno])
+ return reg_base_value[regno];
return src;
if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
break;
- /* ... fall through ... */
+ /* ... 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 (GET_CODE (src_0) == REG)
+ if (REG_P (src_0))
{
temp = find_base_value (src_0);
if (temp != 0)
src_0 = temp;
}
- if (GET_CODE (src_1) == REG)
+ 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. */
else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1))
return find_base_value (src_1);
- /* This might not be necessary anymore:
- If either operand is a REG that is a known pointer, then it
- is the base. */
- else if (GET_CODE (src_0) == REG && REG_POINTER (src_0))
- return find_base_value (src_0);
- else if (GET_CODE (src_1) == REG && REG_POINTER (src_1))
- return find_base_value (src_1);
-
return 0;
}
case AND:
/* If the second operand is constant set the base
- address to the first operand. */
+ 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 ZERO_EXTEND:
- case SIGN_EXTEND: /* used for NT/Alpha pointers */
+ 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;
}
rtx dest, set;
void *data ATTRIBUTE_UNUSED;
{
- register unsigned regno;
+ unsigned regno;
rtx src;
if (GET_CODE (dest) != REG)
switch (GET_CODE (src))
{
case LO_SUM:
- case PLUS:
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;
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
if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1))
{
- /* We can tolerate LO_SUMs being offset here; these
- rtl are used for nothing other than comparisons. */
if (GET_CODE (x0) == CONST_INT)
- return plus_constant_for_output (x1, INTVAL (x0));
+ return plus_constant (x1, INTVAL (x0));
else if (GET_CODE (x1) == CONST_INT)
- return plus_constant_for_output (x0, INTVAL (x1));
+ return plus_constant (x0, INTVAL (x1));
return gen_rtx_PLUS (GET_MODE (x), x0, x1);
}
}
MEM alone, but need to return the canonicalized MEM with
all the flags with their original values. */
else if (GET_CODE (x) == MEM)
- {
- rtx addr = canon_rtx (XEXP (x, 0));
+ x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0)));
- if (addr != XEXP (x, 0))
- {
- rtx new = gen_rtx_MEM (GET_MODE (x), addr);
-
- MEM_COPY_ATTRIBUTES (new, x);
- x = new;
- }
- }
return x;
}
rtx_equal_for_memref_p (x, y)
rtx x, y;
{
- register int i;
- register int j;
- register enum rtx_code code;
- register const char *fmt;
+ int i;
+ int j;
+ enum rtx_code code;
+ const char *fmt;
if (x == 0 && y == 0)
return 1;
/* 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);
return 0;
case ADDRESSOF:
- return (REGNO (XEXP (x, 0)) == REGNO (XEXP (y, 0))
- && XINT (x, 1) == XINT (y, 1));
+ return (XINT (x, 1) == XINT (y, 1)
+ && rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)));
default:
break;
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;
find_symbolic_term (x)
rtx x;
{
- register int i;
- register enum rtx_code code;
- register const char *fmt;
+ int i;
+ enum rtx_code code;
+ const char *fmt;
code = GET_CODE (x);
if (code == SYMBOL_REF || code == LABEL_REF)
static rtx
find_base_term (x)
- register rtx x;
+ rtx x;
{
cselib_val *val;
struct elt_loc_list *l;
case REG:
return REG_BASE_VALUE (x);
- case ZERO_EXTEND:
- case SIGN_EXTEND: /* Used for Alpha/NT pointers */
+ 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)
rtx tmp1 = XEXP (x, 0);
rtx tmp2 = XEXP (x, 1);
- /* This is a litle bit tricky since we have to determine which of
+ /* 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.
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);
}
case AND:
- if (GET_CODE (XEXP (x, 0)) == REG && GET_CODE (XEXP (x, 1)) == CONST_INT)
- return REG_BASE_VALUE (XEXP (x, 0));
+ 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:
if (rtx_equal_p (x_base, y_base))
return 1;
- /* The base addresses of the read and write are different expressions.
+ /* 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,
return 1;
if (GET_CODE (x) == AND
&& (GET_CODE (XEXP (x, 1)) != CONST_INT
- || GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1))))
+ || (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
- || GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
+ || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
return 1;
/* Differing symbols never alias. */
return 0;
if (flag_argument_noalias > 1)
return 0;
- /* Weak noalias assertion (arguments are distinct, but may match globals). */
+ /* Weak noalias assertion (arguments are distinct, but may match globals). */
return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode);
}
it unchanged unless it is a value; in the latter case we call cselib to get
a more useful rtx. */
-static rtx
+rtx
get_addr (x)
rtx x;
{
int n_refs;
{
int offset = 0;
-
+
switch (GET_CODE (addr))
{
case PRE_INC:
default:
return addr;
}
-
+
if (offset)
addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), GEN_INT (offset));
else
static int
memrefs_conflict_p (xsize, x, ysize, y, c)
- register rtx x, y;
+ rtx x, y;
int xsize, ysize;
HOST_WIDE_INT c;
{
}
/* Treat an access through an AND (e.g. a subword access on an Alpha)
- as an access with indeterminate size. Assume that references
+ 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 && 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
+ 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)))
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.
+ 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
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)
+ 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)
+ 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. */
/* 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;
+ }
+ else if (TREE_CODE (exprx) == INDIRECT_REF)
+ {
+ exprx = TREE_OPERAND (exprx, 0);
+ if (flag_argument_noalias < 2
+ || TREE_CODE (exprx) != PARM_DECL)
+ return 0;
+ }
+
+ 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;
+ }
+ else if (TREE_CODE (expry) == INDIRECT_REF)
+ {
+ expry = TREE_OPERAND (expry, 0);
+ if (flag_argument_noalias < 2
+ || TREE_CODE (expry) != PARM_DECL)
+ return 0;
+ }
+
+ 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
rtx x;
int (*varies) PARAMS ((rtx, int));
{
- register rtx x_addr, mem_addr;
+ rtx x_addr, mem_addr;
rtx base;
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
return 1;
+ /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+ This is used in epilogue deallocation functions. */
+ if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+ return 1;
+ if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+ return 1;
+
if (DIFFERENT_ALIAS_SETS_P (x, mem))
return 0;
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);
if (aliases_everything_p (x))
return 1;
- /* We cannot use aliases_everyting_p to test MEM, since we must look
+ /* 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;
+
+ /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+ This is used in epilogue deallocation functions. */
+ if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+ return 1;
+ if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+ 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;
if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
return 1;
+ /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+ This is used in epilogue deallocation functions. */
+ if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+ return 1;
+ if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+ return 1;
+
if (DIFFERENT_ALIAS_SETS_P (x, mem))
return 0;
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));
SIZE_FOR_MODE (x), x_addr, 0))
return 0;
- fixed_scalar
+ fixed_scalar
= fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
rtx_addr_varies_p);
int
output_dependence (mem, x)
- register rtx mem;
- register rtx 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. */
+\f
+/* A subroutine of nonlocal_mentioned_p, returns 1 if *LOC mentions
+ something which is not local to the function and is not constant. */
static int
-nonlocal_mentioned_p (x)
- rtx x;
+nonlocal_mentioned_p_1 (loc, data)
+ rtx *loc;
+ void *data ATTRIBUTE_UNUSED;
{
+ rtx x = *loc;
rtx base;
- register 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_CALL_P (x))
- {
- x = CALL_INSN_FUNCTION_USAGE (x);
- if (x == 0)
- return 0;
- }
- else
- x = PATTERN (x);
- code = GET_CODE (x);
- }
+ if (! x)
+ return 0;
- switch (code)
+ switch (GET_CODE (x))
{
case SUBREG:
if (GET_CODE (SUBREG_REG (x)) == REG)
{
/* Global registers are not local. */
if (REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER
- && global_regs[REGNO (SUBREG_REG (x)) + SUBREG_WORD (x)])
+ && global_regs[subreg_regno (x)])
return 1;
return 0;
}
case CC0:
case CONST_INT:
case CONST_DOUBLE:
+ case CONST_VECTOR:
case CONST:
case LABEL_REF:
return 0;
break;
}
- /* Recursively scan the operands of this expression. */
-
- {
- register const char *fmt = GET_RTX_FORMAT (code);
- register 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')
- {
- register int j;
- for (j = 0; j < XVECLEN (x, i); j++)
- if (nonlocal_mentioned_p (XVECEXP (x, i, j)))
- return 1;
- }
- }
- }
-
return 0;
}
-/* Return non-zero if a loop (natural or otherwise) is present.
- Inspired by Depth_First_Search_PP described in:
+/* Returns non-zero if X might mention something which is not
+ local to the function and is not constant. */
- Advanced Compiler Design and Implementation
- Steven Muchnick
- Morgan Kaufmann, 1997
+static int
+nonlocal_mentioned_p (x)
+ rtx x;
+{
- and heavily borrowed from flow_depth_first_order_compute. */
+ if (INSN_P (x))
+ {
+ if (GET_CODE (x) == CALL_INSN)
+ {
+ if (! CONST_OR_PURE_CALL_P (x))
+ return 1;
+ x = CALL_INSN_FUNCTION_USAGE (x);
+ if (x == 0)
+ return 0;
+ }
+ else
+ x = PATTERN (x);
+ }
+
+ return for_each_rtx (&x, nonlocal_mentioned_p_1, NULL);
+}
+
+/* A subroutine of nonlocal_referenced_p, returns 1 if *LOC references
+ something which is not local to the function and is not constant. */
static int
-loop_p ()
+nonlocal_referenced_p_1 (loc, data)
+ rtx *loc;
+ void *data ATTRIBUTE_UNUSED;
{
- edge *stack;
- int *pre;
- int *post;
- int sp;
- int prenum = 1;
- int postnum = 1;
- sbitmap visited;
+ rtx x = *loc;
- /* Allocate the preorder and postorder number arrays. */
- pre = (int *) xcalloc (n_basic_blocks, sizeof (int));
- post = (int *) xcalloc (n_basic_blocks, sizeof (int));
+ if (! x)
+ return 0;
- /* Allocate stack for back-tracking up CFG. */
- stack = (edge *) xmalloc ((n_basic_blocks + 1) * sizeof (edge));
- sp = 0;
+ switch (GET_CODE (x))
+ {
+ case MEM:
+ case REG:
+ case SYMBOL_REF:
+ case SUBREG:
+ return nonlocal_mentioned_p (x);
- /* Allocate bitmap to track nodes that have been visited. */
- visited = sbitmap_alloc (n_basic_blocks);
+ case CALL:
+ /* Non-constant calls and recursion are not local. */
+ return 1;
- /* None of the nodes in the CFG have been visited yet. */
- sbitmap_zero (visited);
+ case SET:
+ if (nonlocal_mentioned_p (SET_SRC (x)))
+ return 1;
- /* Push the first edge on to the stack. */
- stack[sp++] = ENTRY_BLOCK_PTR->succ;
+ if (GET_CODE (SET_DEST (x)) == MEM)
+ return nonlocal_mentioned_p (XEXP (SET_DEST (x), 0));
+
+ /* If the destination is anything other than a CC0, PC,
+ MEM, REG, or a SUBREG of a REG that occupies all of
+ the REG, then X references nonlocal memory if it is
+ mentioned in the destination. */
+ if (GET_CODE (SET_DEST (x)) != CC0
+ && GET_CODE (SET_DEST (x)) != PC
+ && GET_CODE (SET_DEST (x)) != REG
+ && ! (GET_CODE (SET_DEST (x)) == SUBREG
+ && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG
+ && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x))))
+ + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)
+ == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x)))
+ + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD))))
+ return nonlocal_mentioned_p (SET_DEST (x));
+ return 0;
- while (sp)
- {
- edge e;
- basic_block src;
- basic_block dest;
+ case CLOBBER:
+ if (GET_CODE (XEXP (x, 0)) == MEM)
+ return nonlocal_mentioned_p (XEXP (XEXP (x, 0), 0));
+ return 0;
- /* Look at the edge on the top of the stack. */
- e = stack[sp - 1];
- src = e->src;
- dest = e->dest;
+ case USE:
+ return nonlocal_mentioned_p (XEXP (x, 0));
- /* Check if the edge destination has been visited yet. */
- if (dest != EXIT_BLOCK_PTR && ! TEST_BIT (visited, dest->index))
- {
- /* Mark that we have visited the destination. */
- SET_BIT (visited, dest->index);
+ case ASM_INPUT:
+ case UNSPEC_VOLATILE:
+ return 1;
- pre[dest->index] = prenum++;
+ case ASM_OPERANDS:
+ if (MEM_VOLATILE_P (x))
+ return 1;
- if (dest->succ)
- {
- /* Since the DEST node has been visited for the first
- time, check its successors. */
- stack[sp++] = dest->succ;
- }
- else
- post[dest->index] = postnum++;
+ /* FALLTHROUGH */
+
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+/* Returns non-zero if X might reference something which is not
+ local to the function and is not constant. */
+
+static int
+nonlocal_referenced_p (x)
+ rtx x;
+{
+
+ if (INSN_P (x))
+ {
+ if (GET_CODE (x) == CALL_INSN)
+ {
+ if (! CONST_OR_PURE_CALL_P (x))
+ return 1;
+ x = CALL_INSN_FUNCTION_USAGE (x);
+ if (x == 0)
+ return 0;
}
else
- {
- if (dest != EXIT_BLOCK_PTR
- && pre[src->index] >= pre[dest->index]
- && post[dest->index] == 0)
- break;
+ x = PATTERN (x);
+ }
- if (! e->succ_next && src != ENTRY_BLOCK_PTR)
- post[src->index] = postnum++;
+ return for_each_rtx (&x, nonlocal_referenced_p_1, NULL);
+}
- if (e->succ_next)
- stack[sp - 1] = e->succ_next;
- else
- sp--;
- }
+/* A subroutine of nonlocal_set_p, returns 1 if *LOC sets
+ something which is not local to the function and is not constant. */
+
+static int
+nonlocal_set_p_1 (loc, data)
+ rtx *loc;
+ void *data ATTRIBUTE_UNUSED;
+{
+ rtx x = *loc;
+
+ if (! x)
+ return 0;
+
+ switch (GET_CODE (x))
+ {
+ case CALL:
+ /* Non-constant calls and recursion are not local. */
+ return 1;
+
+ case PRE_INC:
+ case PRE_DEC:
+ case POST_INC:
+ case POST_DEC:
+ case PRE_MODIFY:
+ case POST_MODIFY:
+ return nonlocal_mentioned_p (XEXP (x, 0));
+
+ case SET:
+ if (nonlocal_mentioned_p (SET_DEST (x)))
+ return 1;
+ return nonlocal_set_p (SET_SRC (x));
+
+ case CLOBBER:
+ return nonlocal_mentioned_p (XEXP (x, 0));
+
+ case USE:
+ return 0;
+
+ case ASM_INPUT:
+ case UNSPEC_VOLATILE:
+ return 1;
+
+ case ASM_OPERANDS:
+ if (MEM_VOLATILE_P (x))
+ return 1;
+
+ /* FALLTHROUGH */
+
+ default:
+ break;
}
- free (pre);
- free (post);
- free (stack);
- sbitmap_free (visited);
+ return 0;
+}
- return sp;
+/* Returns non-zero if X might set something which is not
+ local to the function and is not constant. */
+
+static int
+nonlocal_set_p (x)
+ rtx x;
+{
+
+ if (INSN_P (x))
+ {
+ if (GET_CODE (x) == CALL_INSN)
+ {
+ if (! CONST_OR_PURE_CALL_P (x))
+ return 1;
+ x = CALL_INSN_FUNCTION_USAGE (x);
+ if (x == 0)
+ return 0;
+ }
+ else
+ x = PATTERN (x);
+ }
+
+ return for_each_rtx (&x, nonlocal_set_p_1, NULL);
}
/* Mark the function if it is constant. */
mark_constant_function ()
{
rtx insn;
- int nonlocal_mentioned;
+ int nonlocal_memory_referenced;
- if (TREE_PUBLIC (current_function_decl)
- || TREE_READONLY (current_function_decl)
+ if (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)
+ || TYPE_MODE (TREE_TYPE (current_function_decl)) == VOIDmode
+ || current_function_has_nonlocal_goto
+ || !(*targetm.binds_local_p) (current_function_decl))
return;
/* A loop might not return which counts as a side effect. */
- if (loop_p ())
+ if (mark_dfs_back_edges ())
return;
- nonlocal_mentioned = 0;
+ nonlocal_memory_referenced = 0;
init_alias_analysis ();
- /* Determine if this is a constant function. */
+ /* Determine if this is a constant or pure function. */
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
- if (INSN_P (insn) && nonlocal_mentioned_p (insn))
- {
- nonlocal_mentioned = 1;
+ {
+ if (! INSN_P (insn))
+ continue;
+
+ if (nonlocal_set_p (insn) || global_reg_mentioned_p (insn)
+ || volatile_refs_p (PATTERN (insn)))
break;
- }
+
+ if (! nonlocal_memory_referenced)
+ nonlocal_memory_referenced = nonlocal_referenced_p (insn);
+ }
end_alias_analysis ();
/* Mark the function. */
- if (! nonlocal_mentioned)
+ if (insn)
+ ;
+ else if (nonlocal_memory_referenced)
+ DECL_IS_PURE (current_function_decl) = 1;
+ else
TREE_READONLY (current_function_decl) = 1;
}
-
-
-static HARD_REG_SET argument_registers;
+\f
void
init_alias_once ()
{
- register int i;
+ int i;
#ifndef OUTGOING_REGNO
#define OUTGOING_REGNO(N) N
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. */
+ 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);
+ static_reg_base_value[i]
+ = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i));
+
+ static_reg_base_value[STACK_POINTER_REGNUM]
+ = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx);
+ static_reg_base_value[ARG_POINTER_REGNUM]
+ = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx);
+ static_reg_base_value[FRAME_POINTER_REGNUM]
+ = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx);
+#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
+ static_reg_base_value[HARD_FRAME_POINTER_REGNUM]
+ = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx);
+#endif
alias_sets = splay_tree_new (splay_tree_compare_ints, 0, 0);
}
{
int maxreg = max_reg_num ();
int changed, pass;
- register int i;
- register unsigned int ui;
- register rtx insn;
+ int i;
+ unsigned int ui;
+ rtx insn;
reg_known_value_size = maxreg;
- reg_known_value
+ reg_known_value
= (rtx *) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (rtx))
- FIRST_PSEUDO_REGISTER;
- reg_known_equiv_p
+ reg_known_equiv_p
= (char*) xcalloc ((maxreg - FIRST_PSEUDO_REGISTER), sizeof (char))
- FIRST_PSEUDO_REGISTER;
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);
+ reg_base_value = (rtx *) ggc_alloc_cleared (reg_base_value_size
+ * sizeof (rtx));
new_reg_base_value = (rtx *) xmalloc (reg_base_value_size * sizeof (rtx));
reg_seen = (char *) xmalloc (reg_base_value_size);
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
start counting from zero each iteration of the loop. */
unique_id = 0;
- /* We're at the start of the funtion each iteration through the
+ /* We're at the start of the function each iteration through the
loop, so we're copying arguments. */
copying_arguments = 1;
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
+ memcpy (new_reg_base_value, static_reg_base_value,
+ FIRST_PSEUDO_REGISTER * sizeof (rtx));
/* Walk the insns adding values to the new_reg_base_value array. */
for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
rtx note, set;
#if defined (HAVE_prologue) || defined (HAVE_epilogue)
- /* The prologue/epilouge insns are not threaded onto the
+ /* 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 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. */
+ which could change the base value of any other register. */
if (GET_CODE (PATTERN (insn)) == SET
&& REG_NOTES (insn) != 0
if (set != 0
&& GET_CODE (SET_DEST (set)) == REG
- && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER
- && REG_NOTES (insn) != 0
- && (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0
- && REG_N_SETS (REGNO (SET_DEST (set))) == 1)
- || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0)
- && GET_CODE (XEXP (note, 0)) != EXPR_LIST
- && ! reg_overlap_mentioned_p (SET_DEST (set), XEXP (note, 0)))
+ && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER)
{
- int regno = REGNO (SET_DEST (set));
- reg_known_value[regno] = XEXP (note, 0);
- reg_known_equiv_p[regno] = REG_NOTE_KIND (note) == REG_EQUIV;
+ 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
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 = 0;
reg_base_value_size = 0;
if (alias_invariant)
{
alias_invariant = 0;
}
}
+
+#include "gt-alias.h"
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