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explow.c (maybe_set_unchanging): New function, broken out from...

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* explow.c (maybe_set_unchanging): New function, broken out from...
        (set_mem_attributes): Here.
        * expr.h: Declare it.
        * stmt.c (expand_decl): Call it.

From-SVN: r34421
This commit is contained in:
Jason Merrill 2000-06-06 03:37:50 +00:00 • committed by Jason Merrill
parent c9d8a81361
commit 258a120bab
4 changed files with 41 additions and 6 deletions
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7
gcc/ChangeLog
View file

@ -1,3 +1,10 @@
2000-06-05 Jason Merrill <jason@casey.soma.redhat.com>
* explow.c (maybe_set_unchanging): New function, broken out from...
(set_mem_attributes): Here.
* expr.h: Declare it.
* stmt.c (expand_decl): Call it.
2000-06-05 Richard Henderson <rth@cygnus.com>
* reload1.c (choose_reload_regs): Mind CLASS_CANNOT_CHANGE_SIZE

30
gcc/explow.c
View file

@ -628,6 +628,27 @@ validize_mem (ref)
return change_address (ref, GET_MODE (ref), XEXP (ref, 0));
}
/* Given REF, either a MEM or a REG, and T, either the type of X or
the expression corresponding to REF, set RTX_UNCHANGING_P if
appropriate. */
void
maybe_set_unchanging (ref, t)
rtx ref;
tree t;
{
/* We can set RTX_UNCHANGING_P from TREE_READONLY for decls whose
initialization is only executed once, or whose initializer always
has the same value. Currently we simplify this to PARM_DECLs in the
first case, and decls with TREE_CONSTANT initializers in the second. */
if ((TREE_READONLY (t) && DECL_P (t)
&& (TREE_CODE (t) == PARM_DECL
|| DECL_INITIAL (t) == NULL_TREE
|| TREE_CONSTANT (DECL_INITIAL (t))))
|| TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
RTX_UNCHANGING_P (ref) = 1;
}
/* Given REF, a MEM, and T, either the type of X or the expression
corresponding to REF, set the memory attributes. OBJECTP is nonzero
if we are making a new object of this type. */
@ -642,8 +663,12 @@ set_mem_attributes (ref, t, objectp)
/* Get the alias set from the expression or type (perhaps using a
front-end routine) and then copy bits from the type. */
/* 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_ALIAS_SET (ref) = get_alias_set (t);
RTX_UNCHANGING_P (ref) = TYPE_READONLY (type);
MEM_VOLATILE_P (ref) = TYPE_VOLATILE (type);
MEM_IN_STRUCT_P (ref) = AGGREGATE_TYPE_P (type);
@ -657,8 +682,7 @@ set_mem_attributes (ref, t, objectp)
if (TYPE_P (t))
return;
if (TREE_READONLY (t) || TREE_CODE_CLASS (TREE_CODE (t)) == 'c')
RTX_UNCHANGING_P (ref) = 1;
maybe_set_unchanging (ref, t);
if (TREE_THIS_VOLATILE (t))
MEM_VOLATILE_P (ref) = 1;

5
gcc/expr.h
View file

@ -1150,6 +1150,11 @@ extern rtx change_address PARAMS ((rtx, enum machine_mode, rtx));
extern rtx validize_mem PARAMS ((rtx));
#ifdef TREE_CODE
/* Given REF, either a MEM or a REG, and T, either the type of X or
the expression corresponding to REF, set RTX_UNCHANGING_P if
appropriate. */
extern void maybe_set_unchanging PARAMS ((rtx, tree));
/* Given REF, a MEM, and T, either the type of X or the expression
corresponding to REF, set the memory attributes. OBJECTP is nonzero
if we are making a new object of this type. */

5
gcc/stmt.c
View file

@ -3817,9 +3817,8 @@ expand_decl (decl)
if (POINTER_TYPE_P (type))
mark_reg_pointer (DECL_RTL (decl),
TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
if (TREE_READONLY (decl))
RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
maybe_set_unchanging (DECL_RTL (decl), decl);
}
else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST