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alias.c (handled_component_p, [...]): New functions. 

* alias.c (handled_component_p, can_address_p): New functions.
	(get_alias_set): Use them.

From-SVN: r40449
This commit is contained in:
Richard Kenner 2001-03-14 03:21:43 +00:00 committed by Richard Kenner
parent 9502c55830
commit 6e24b709a1
2 changed files with 62 additions and 29 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Tue Mar 13 22:22:04 2001 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* alias.c (handled_component_p, can_address_p): New functions.
(get_alias_set): Use them.
2001-03-13 Jim Wilson <wilson@redhat.com>
* config/ia64/ia64.c (find_gr_spill): Subtract frame_pointer_needed

86
gcc/alias.c
View File

@ -1,5 +1,5 @@
/* 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.
@ -95,6 +95,8 @@ 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 int handled_component_p PARAMS ((tree));
static int can_address_p PARAMS ((tree));
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*));
@ -400,6 +402,58 @@ find_base_decl (t)
}
}
/* Return 1 if T is an expression that get_inner_reference handles. */
static int
handled_component_p (t)
tree t;
{
switch (TREE_CODE (t))
{
case BIT_FIELD_REF:
case COMPONENT_REF:
case ARRAY_REF:
case NON_LVALUE_EXPR:
return 1;
case NOP_EXPR:
case CONVERT_EXPR:
return (TYPE_MODE (TREE_TYPE (t))
== TYPE_MODE (TREE_TYPE (TREE_OPERAND (t, 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. */
static 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;
else if (TREE_CODE (t) == COMPONENT_REF
&& ! DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))
&& can_address_p (TREE_OPERAND (t, 0)))
return 1;
else if (TREE_CODE (t) == ARRAY_REF
&& ! TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 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. */
@ -439,35 +493,9 @@ get_alias_set (t)
/* 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)
{
/* 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;
while (handled_component_p (t) && ! can_address_p (t))
t = TREE_OPERAND (t, 0);
t = TREE_OPERAND (t, 0);
}
if (TREE_CODE (t) == INDIRECT_REF)
{
/* Check for accesses through restrict-qualified pointers. */