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langhooks.h (LANG_HOOKS_HONOR_READONLY): New macro.

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* langhooks.h (LANG_HOOKS_HONOR_READONLY): New macro.
	* toplev.h (struct lang_hooks): New field HONOR_READONLY.
	* emit-rtl.c (set_mem_attributes): Set RTX_UNCHANGING_P from
	TREE_READONLY and TYPE_READONLY if lang_hooks.honor_readonly.
	Set alignment from type if INDIRECT_REF.
	(adjust_address_1, offset_address): Simplify alignment compuitation.
	* expr.c (expand_expr, case INDIRECT_REF): Don't set RTX_UNCHANGING_P
	here; done by set_mem_attributes.

From-SVN: r46361
This commit is contained in:
Richard Kenner 2001-10-19 19:54:06 +00:00 • committed by Richard Kenner
parent 91ea4f8ddf
commit 03bf2c237c
5 changed files with 31 additions and 25 deletions
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11
gcc/ChangeLog
View file

@ -1,3 +1,14 @@
Fri Oct 19 15:24:39 2001 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* langhooks.h (LANG_HOOKS_HONOR_READONLY): New macro.
* toplev.h (struct lang_hooks): New field HONOR_READONLY.
* emit-rtl.c (set_mem_attributes): Set RTX_UNCHANGING_P from
TREE_READONLY and TYPE_READONLY if lang_hooks.honor_readonly.
Set alignment from type if INDIRECT_REF.
(adjust_address_1, offset_address): Simplify alignment compuitation.
* expr.c (expand_expr, case INDIRECT_REF): Don't set RTX_UNCHANGING_P
here; done by set_mem_attributes.
2001-10-19 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* Makefile.in (rtlanal.o): Depend on $(TM_P_H).

31
gcc/emit-rtl.c
View file

@ -1672,13 +1672,11 @@ set_mem_attributes (ref, t, objectp)
front-end routine). */
set_mem_alias_set (ref, get_alias_set (t));
/* It is incorrect to set RTX_UNCHANGING_P from TREE_READONLY (type)
here, because, in C and C++, the fact that a location is accessed
through a const expression does not mean that the value there can
never change. */
MEM_VOLATILE_P (ref) = TYPE_VOLATILE (type);
MEM_IN_STRUCT_P (ref) = AGGREGATE_TYPE_P (type);
RTX_UNCHANGING_P (ref)
|= (lang_hooks.honor_readonly
&& (TYPE_READONLY (type) || TREE_READONLY (t)));
/* If we are making an object of this type, we know that it is a scalar if
the type is not an aggregate. */
@ -1717,6 +1715,10 @@ set_mem_attributes (ref, t, objectp)
? GEN_INT (tree_low_cst (TYPE_SIZE_UNIT (TREE_TYPE (t)), 1))
: 0, DECL_ALIGN (t) / BITS_PER_UNIT);
/* If this is an INDIRECT_REF, we know its alignment. */
if (TREE_CODE (t) == INDIRECT_REF)
set_mem_align (ref, TYPE_ALIGN (type) / BITS_PER_UNIT);
/* Now see if we can say more about whether it's an aggregate or
scalar. If we already know it's an aggregate, don't bother. */
if (MEM_IN_STRUCT_P (ref))
@ -1860,14 +1862,11 @@ adjust_address_1 (memref, mode, offset, validate)
if (memoffset)
memoffset = GEN_INT (offset + INTVAL (memoffset));
/* If the offset is negative, don't try to update the alignment. If it's
zero, the alignment hasn't changed. Otherwise, the known alignment may
be less strict. */
if (offset < 0)
memalign = 1;
while (offset > 0 && (offset % memalign) != 0)
memalign >>= 1;
/* Compute the new alignment by taking the MIN of the alignment and the
lowest-order set bit in OFFSET, but don't change the alignment if OFFSET
if zero. */
if (offset != 0)
memalign = MIN (memalign, offset & -offset);
MEM_ATTRS (new)
= get_mem_attrs (MEM_ALIAS_SET (memref), MEM_DECL (memref), memoffset,
@ -1893,15 +1892,11 @@ offset_address (memref, offset, pow2)
rtx new = change_address_1 (memref, VOIDmode,
gen_rtx_PLUS (Pmode, XEXP (memref, 0),
force_reg (Pmode, offset)), 1);
unsigned int memalign = MEM_ALIGN (memref);
/* Update the alignment to reflect the offset. Reset the offset, which
we don't know. */
while (pow2 % memalign != 0)
memalign >>= 1;
MEM_ATTRS (new) = get_mem_attrs (MEM_ALIAS_SET (memref), MEM_DECL (memref),
0, 0, memalign);
0, 0, MIN (MEM_ALIGN (memref), pow2));
return new;
}

7
gcc/expr.c
View file

@ -6812,13 +6812,6 @@ expand_expr (exp, target, tmode, modifier)
temp = gen_rtx_MEM (mode, op0);
set_mem_attributes (temp, exp, 0);
/* It is incorrect to set RTX_UNCHANGING_P from TREE_READONLY
here, because, in C and C++, the fact that a location is accessed
through a pointer to const does not mean that the value there can
never change. Languages where it can never change should
also set TREE_STATIC. */
RTX_UNCHANGING_P (temp) = TREE_READONLY (exp) & TREE_STATIC (exp);
/* If we are writing to this object and its type is a record with
readonly fields, we must mark it as readonly so it will
conflict with readonly references to those fields. */

4
gcc/langhooks.h
View file

@ -39,6 +39,9 @@ Boston, MA 02111-1307, USA. */
#ifndef LANG_HOOKS_POST_OPTIONS
#define LANG_HOOKS_POST_OPTIONS NULL
#endif
#ifndef LANG_HOOKS_HONOR_READONLY
#define LANG_HOOKS_HONOR_READONLY 0
#endif
/* Declarations of default tree inlining hooks. */
tree tree_inlining_default_hook_walk_subtrees PARAMS ((tree*, int *,
@ -108,6 +111,7 @@ int tree_inlining_default_hook_anon_aggr_type_p PARAMS ((tree));
LANG_HOOKS_INIT_OPTIONS, \
LANG_HOOKS_DECODE_OPTION, \
LANG_HOOKS_POST_OPTIONS, \
LANG_HOOKS_HONOR_READONLY, \
LANG_HOOKS_TREE_INLINING_INITIALIZER \
}

3
gcc/toplev.h
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@ -166,6 +166,9 @@ struct lang_hooks
/* Called when all command line options have been processed. */
void (*post_options) PARAMS ((void));
/* Nonzero if TYPE_READONLY and TREE_READONLY should always be honored. */
int honor_readonly;
struct lang_hooks_for_tree_inlining tree_inlining;
/* Whenever you add entries here, make sure you adjust langhooks.h