OpenE2K/gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

tree.c (int_fits_type_p): Extract generic checks from the case of constant type bounds.

Browse Source 
* tree.c (int_fits_type_p): Extract generic checks from the case
	of constant type bounds. Refine the checks against constant type
	bounds to allow for possible decisions against each of these bounds
	without requiring both bounds to be constant.
	(tree_int_cst_msb): Put back.
	* tree.h (tree_int_cst_msb): Likewise.

From-SVN: r65598
This commit is contained in:
Olivier Hainque 2003-04-14 23:59:54 +02:00 committed by Richard Kenner
parent 4147232b5c
commit 4694840a01
3 changed files with 74 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
gcc/ChangeLog
View File

@ -17,6 +17,13 @@
2003-04-14 Olivier Hainque <hainque@act-europe.fr>
* tree.c (int_fits_type_p): Extract generic checks from the case
of constant type bounds. Refine the checks against constant type
bounds to allow for possible decisions against each of these bounds
without requiring both bounds to be constant.
(tree_int_cst_msb): Put back.
* tree.h (tree_int_cst_msb): Likewise.
* global.c (global_conflicts): Prevent allocation of call clobbered
hard regs to pseudos live across abnormal edges, as later passes are
not ready to handle them.

85
gcc/tree.c
View File

@ -3245,6 +3245,24 @@ tree_low_cst (t, pos)
abort ();
}
/* Return the most significant bit of the integer constant T. */
int
tree_int_cst_msb (t)
tree t;
{
int prec;
HOST_WIDE_INT h;
unsigned HOST_WIDE_INT l;
/* Note that using TYPE_PRECISION here is wrong. We care about the
actual bits, not the (arbitrary) range of the type. */
prec = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (t))) - 1;
rshift_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t), prec,
2 * HOST_BITS_PER_WIDE_INT, &l, &h, 0);
return (l & 1) == 1;
}
/* Return an indication of the sign of the integer constant T.
The return value is -1 if T < 0, 0 if T == 0, and 1 if T > 0.
Note that -1 will never be returned it T's type is unsigned. */
@ -4069,29 +4087,58 @@ int
int_fits_type_p (c, type)
tree c, type;
{
/* If the bounds of the type are integers, we can check ourselves.
If not, but this type is a subtype, try checking against that.
Otherwise, use force_fit_type, which checks against the precision. */
if (TYPE_MAX_VALUE (type) != NULL_TREE
&& TYPE_MIN_VALUE (type) != NULL_TREE
&& TREE_CODE (TYPE_MAX_VALUE (type)) == INTEGER_CST
&& TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST)
tree type_low_bound = TYPE_MIN_VALUE (type);
tree type_high_bound = TYPE_MAX_VALUE (type);
int ok_for_low_bound, ok_for_high_bound;
/* Perform some generic filtering first, which may allow making a decision
even if the bounds are not constant. First, negative integers never fit
in unsigned types, */
if ((TREE_UNSIGNED (type) && tree_int_cst_sgn (c) < 0)
/* Also, unsigned integers with top bit set never fit signed types. */
|| (! TREE_UNSIGNED (type)
&& TREE_UNSIGNED (TREE_TYPE (c)) && tree_int_cst_msb (c)))
return 0;
/* If at least one bound of the type is a constant integer, we can check
ourselves and maybe make a decision. If no such decision is possible, but
this type is a subtype, try checking against that. Otherwise, use
force_fit_type, which checks against the precision.
Compute the status for each possibly constant bound, and return if we see
one does not match. Use ok_for_xxx_bound for this purpose, assigning -1
for "unknown if constant fits", 0 for "constant known *not* to fit" and 1
for "constant known to fit". */
ok_for_low_bound = -1;
ok_for_high_bound = -1;
/* Check if C >= type_low_bound. */
if (type_low_bound && TREE_CODE (type_low_bound) == INTEGER_CST)
{
if (TREE_UNSIGNED (type))
return (! INT_CST_LT_UNSIGNED (TYPE_MAX_VALUE (type), c)
&& ! INT_CST_LT_UNSIGNED (c, TYPE_MIN_VALUE (type))
/* Negative ints never fit unsigned types. */
&& ! (TREE_INT_CST_HIGH (c) < 0
&& ! TREE_UNSIGNED (TREE_TYPE (c))));
else
return (! INT_CST_LT (TYPE_MAX_VALUE (type), c)
&& ! INT_CST_LT (c, TYPE_MIN_VALUE (type))
/* Unsigned ints with top bit set never fit signed types. */
&& ! (TREE_INT_CST_HIGH (c) < 0
&& TREE_UNSIGNED (TREE_TYPE (c))));
ok_for_low_bound = ! tree_int_cst_lt (c, type_low_bound);
if (! ok_for_low_bound)
return 0;
}
/* Check if c <= type_high_bound. */
if (type_high_bound && TREE_CODE (type_high_bound) == INTEGER_CST)
{
ok_for_high_bound = ! tree_int_cst_lt (type_high_bound, c);
if (! ok_for_high_bound)
return 0;
}
/* If the constant fits both bounds, the result is known. */
if (ok_for_low_bound == 1 && ok_for_high_bound == 1)
return 1;
/* If we haven't been able to decide at this point, there nothing more we
can check ourselves here. Look at the base type if we have one. */
else if (TREE_CODE (type) == INTEGER_TYPE && TREE_TYPE (type) != 0)
return int_fits_type_p (c, TREE_TYPE (type));
/* Or to force_fit_type, if nothing else. */
else
{
c = copy_node (c);

1
gcc/tree.h
View File

@ -2300,6 +2300,7 @@ extern int tree_int_cst_lt PARAMS ((tree, tree));
extern int tree_int_cst_compare PARAMS ((tree, tree));
extern int host_integerp PARAMS ((tree, int));
extern HOST_WIDE_INT tree_low_cst PARAMS ((tree, int));
extern int tree_int_cst_msb PARAMS ((tree));
extern int tree_int_cst_sgn PARAMS ((tree));
extern int tree_expr_nonnegative_p PARAMS ((tree));
extern int rtl_expr_nonnegative_p PARAMS ((rtx));