For some reason I split out sanitizing sizetypes from the
no-undefined-overflow-branch. In fact the following patch tries
to only fix one thing - make unsigned sizetypes no longer sign-extended.
This has (unfortunately) interesting side-effects, and some of them
have been mitigated by already committed patches during the last half
year. The main remaining issue I run into (and that sort-of blocks
me from persuing this really really ...) is that there is a lot of
code in GCC that assumes it can do modulo arithmetic on HOST_WIDE_INTs
for sizetypes (pointers / offsets in general). Which happens to
be wrong when a HOST_WIDE_INT is wider than sizetype (on -m32 multilib
on x86_64 for example). It happens to work in almost all cases
if we sign-extend from 32bit to 64bit HWI but not when we zero-extend.
I'm not exactly sure how to proceeed here, other than adding fixups
to various places (as seen in the patch below) and hope to catch
all existing errors. [yes, I already tried making all sizetypes
signed, really signed, but that has loads of fallout as well]
That said, the fact that sizetypes are sign-extended has caused
wrong-code bugs in the past, and TYPE_UNSIGNED is really used
inconsistently. So I think this is definitely worth fixing.
Eventually a first move would be to (finally) get rid of the
requirement of sizetype offset arguments for POINTER_PLUS_EXPR.
I didn't yet start on that project though.
I remember the following bootstrapped fine on x86_64-unknown-linux-gnu
at least for C, with a few remaining regressions. I'm trying
a full all-lang bootstrap & regtest now.
Comments? Questions?
Thanks,
Richard.
2011-06-16 Richard Guenther <rguent...@suse.de>
* fold-const.c (div_if_zero_remainder): sizetypes no longer
sign-extend.
* stor-layout.c (initialize_sizetypes): Likewise.
* tree-ssa-ccp.c (bit_value_unop_1): Likewise.
(bit_value_binop_1): Likewise.
* tree.c (double_int_to_tree): Likewise.
(double_int_fits_to_tree_p): Likewise.
(force_fit_type_double): Likewise.
(host_integerp): Likewise.
(int_fits_type_p): Likewise.
* expr.c (get_inner_reference): Sign-extend offset.
* tree-ssa-structalias.c (get_constraint_for_ptr_offset): Likewise.
* tree-cfg.c (verify_types_in_gimple_reference): Do not compare
sizes by pointer.
Index: trunk/gcc/fold-const.c
===================================================================
*** trunk.orig/gcc/fold-const.c 2011-06-10 12:57:13.000000000 +0200
--- trunk/gcc/fold-const.c 2011-06-14 15:29:04.000000000 +0200
*************** div_if_zero_remainder (enum tree_code co
*** 194,202 ****
does the correct thing for POINTER_PLUS_EXPR where we want
a signed division. */
uns = TYPE_UNSIGNED (TREE_TYPE (arg2));
- if (TREE_CODE (TREE_TYPE (arg2)) == INTEGER_TYPE
- && TYPE_IS_SIZETYPE (TREE_TYPE (arg2)))
- uns = false;
quo = double_int_divmod (tree_to_double_int (arg1),
tree_to_double_int (arg2),
--- 194,199 ----
Index: trunk/gcc/stor-layout.c
===================================================================
*** trunk.orig/gcc/stor-layout.c 2011-06-09 14:49:35.000000000 +0200
--- trunk/gcc/stor-layout.c 2011-06-14 15:31:36.000000000 +0200
*************** initialize_sizetypes (void)
*** 2232,2242 ****
TYPE_SIZE_UNIT (sizetype) = size_int (GET_MODE_SIZE (TYPE_MODE (sizetype)));
set_min_and_max_values_for_integral_type (sizetype, precision,
/*is_unsigned=*/true);
- /* sizetype is unsigned but we need to fix TYPE_MAX_VALUE so that it is
- sign-extended in a way consistent with force_fit_type. */
- TYPE_MAX_VALUE (sizetype)
- = double_int_to_tree (sizetype,
- tree_to_double_int (TYPE_MAX_VALUE (sizetype)));
SET_TYPE_MODE (bitsizetype, smallest_mode_for_size (bprecision, MODE_INT));
TYPE_ALIGN (bitsizetype) = GET_MODE_ALIGNMENT (TYPE_MODE (bitsizetype));
--- 2232,2237 ----
*************** initialize_sizetypes (void)
*** 2245,2251 ****
= size_int (GET_MODE_SIZE (TYPE_MODE (bitsizetype)));
set_min_and_max_values_for_integral_type (bitsizetype, bprecision,
/*is_unsigned=*/true);
- /* ??? TYPE_MAX_VALUE is not properly sign-extended. */
/* Create the signed variants of *sizetype. */
ssizetype = make_signed_type (TYPE_PRECISION (sizetype));
--- 2240,2245 ----
Index: trunk/gcc/tree-ssa-ccp.c
===================================================================
*** trunk.orig/gcc/tree-ssa-ccp.c 2011-05-03 15:05:25.000000000 +0200
--- trunk/gcc/tree-ssa-ccp.c 2011-06-14 15:29:04.000000000 +0200
*************** bit_value_unop_1 (enum tree_code code, t
*** 1152,1165 ****
bool uns;
/* First extend mask and value according to the original type. */
! uns = (TREE_CODE (rtype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (rtype)
! ? 0 : TYPE_UNSIGNED (rtype));
*mask = double_int_ext (rmask, TYPE_PRECISION (rtype), uns);
*val = double_int_ext (rval, TYPE_PRECISION (rtype), uns);
/* Then extend mask and value according to the target type. */
! uns = (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type)
! ? 0 : TYPE_UNSIGNED (type));
*mask = double_int_ext (*mask, TYPE_PRECISION (type), uns);
*val = double_int_ext (*val, TYPE_PRECISION (type), uns);
break;
--- 1152,1163 ----
bool uns;
/* First extend mask and value according to the original type. */
! uns = TYPE_UNSIGNED (rtype);
*mask = double_int_ext (rmask, TYPE_PRECISION (rtype), uns);
*val = double_int_ext (rval, TYPE_PRECISION (rtype), uns);
/* Then extend mask and value according to the target type. */
! uns = TYPE_UNSIGNED (type);
*mask = double_int_ext (*mask, TYPE_PRECISION (type), uns);
*val = double_int_ext (*val, TYPE_PRECISION (type), uns);
break;
*************** bit_value_binop_1 (enum tree_code code,
*** 1181,1188 ****
tree r1type, double_int r1val, double_int r1mask,
tree r2type, double_int r2val, double_int r2mask)
{
! bool uns = (TREE_CODE (type) == INTEGER_TYPE
! && TYPE_IS_SIZETYPE (type) ? 0 : TYPE_UNSIGNED (type));
/* Assume we'll get a constant result. Use an initial varying value,
we fall back to varying in the end if necessary. */
*mask = double_int_minus_one;
--- 1179,1185 ----
tree r1type, double_int r1val, double_int r1mask,
tree r2type, double_int r2val, double_int r2mask)
{
! bool uns = TYPE_UNSIGNED (type);
/* Assume we'll get a constant result. Use an initial varying value,
we fall back to varying in the end if necessary. */
*mask = double_int_minus_one;
*************** bit_value_binop_1 (enum tree_code code,
*** 1249,1261 ****
}
else if (shift < 0)
{
- /* ??? We can have sizetype related inconsistencies in
- the IL. */
- if ((TREE_CODE (r1type) == INTEGER_TYPE
- && (TYPE_IS_SIZETYPE (r1type)
- ? 0 : TYPE_UNSIGNED (r1type))) != uns)
- break;
-
shift = -shift;
*mask = double_int_rshift (r1mask, shift,
TYPE_PRECISION (type), !uns);
--- 1246,1251 ----
*************** bit_value_binop_1 (enum tree_code code,
*** 1367,1378 ****
break;
/* For comparisons the signedness is in the comparison operands. */
! uns = (TREE_CODE (r1type) == INTEGER_TYPE
! && TYPE_IS_SIZETYPE (r1type) ? 0 : TYPE_UNSIGNED (r1type));
! /* ??? We can have sizetype related inconsistencies in the IL. */
! if ((TREE_CODE (r2type) == INTEGER_TYPE
! && TYPE_IS_SIZETYPE (r2type) ? 0 : TYPE_UNSIGNED (r2type)) != uns)
! break;
/* If we know the most significant bits we know the values
value ranges by means of treating varying bits as zero
--- 1357,1363 ----
break;
/* For comparisons the signedness is in the comparison operands. */
! uns = TYPE_UNSIGNED (r1type);
/* If we know the most significant bits we know the values
value ranges by means of treating varying bits as zero
Index: trunk/gcc/tree.c
===================================================================
*** trunk.orig/gcc/tree.c 2011-06-07 16:36:52.000000000 +0200
--- trunk/gcc/tree.c 2011-06-14 15:29:04.000000000 +0200
*************** tree
*** 1051,1059 ****
double_int_to_tree (tree type, double_int cst)
{
/* Size types *are* sign extended. */
! bool sign_extended_type = (!TYPE_UNSIGNED (type)
! || (TREE_CODE (type) == INTEGER_TYPE
! && TYPE_IS_SIZETYPE (type)));
cst = double_int_ext (cst, TYPE_PRECISION (type), !sign_extended_type);
--- 1051,1057 ----
double_int_to_tree (tree type, double_int cst)
{
/* Size types *are* sign extended. */
! bool sign_extended_type = !TYPE_UNSIGNED (type);
cst = double_int_ext (cst, TYPE_PRECISION (type), !sign_extended_type);
*************** bool
*** 1067,1075 ****
double_int_fits_to_tree_p (const_tree type, double_int cst)
{
/* Size types *are* sign extended. */
! bool sign_extended_type = (!TYPE_UNSIGNED (type)
! || (TREE_CODE (type) == INTEGER_TYPE
! && TYPE_IS_SIZETYPE (type)));
double_int ext
= double_int_ext (cst, TYPE_PRECISION (type), !sign_extended_type);
--- 1065,1071 ----
double_int_fits_to_tree_p (const_tree type, double_int cst)
{
/* Size types *are* sign extended. */
! bool sign_extended_type = !TYPE_UNSIGNED (type);
double_int ext
= double_int_ext (cst, TYPE_PRECISION (type), !sign_extended_type);
*************** force_fit_type_double (tree type, double
*** 1099,1107 ****
bool sign_extended_type;
/* Size types *are* sign extended. */
! sign_extended_type = (!TYPE_UNSIGNED (type)
! || (TREE_CODE (type) == INTEGER_TYPE
! && TYPE_IS_SIZETYPE (type)));
/* If we need to set overflow flags, return a new unshared node. */
if (overflowed || !double_int_fits_to_tree_p(type, cst))
--- 1095,1101 ----
bool sign_extended_type;
/* Size types *are* sign extended. */
! sign_extended_type = !TYPE_UNSIGNED (type);
/* If we need to set overflow flags, return a new unshared node. */
if (overflowed || !double_int_fits_to_tree_p(type, cst))
*************** host_integerp (const_tree t, int pos)
*** 6425,6433 ****
&& (HOST_WIDE_INT) TREE_INT_CST_LOW (t) >= 0)
|| (! pos && TREE_INT_CST_HIGH (t) == -1
&& (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0
! && (!TYPE_UNSIGNED (TREE_TYPE (t))
! || (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
! && TYPE_IS_SIZETYPE (TREE_TYPE (t)))))
|| (pos && TREE_INT_CST_HIGH (t) == 0)));
}
--- 6419,6425 ----
&& (HOST_WIDE_INT) TREE_INT_CST_LOW (t) >= 0)
|| (! pos && TREE_INT_CST_HIGH (t) == -1
&& (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0
! && !TYPE_UNSIGNED (TREE_TYPE (t)))
|| (pos && TREE_INT_CST_HIGH (t) == 0)));
}
*************** int_fits_type_p (const_tree c, const_tre
*** 8117,8134 ****
dc = tree_to_double_int (c);
unsc = TYPE_UNSIGNED (TREE_TYPE (c));
- if (TREE_CODE (TREE_TYPE (c)) == INTEGER_TYPE
- && TYPE_IS_SIZETYPE (TREE_TYPE (c))
- && unsc)
- /* So c is an unsigned integer whose type is sizetype and type is not.
- sizetype'd integers are sign extended even though they are
- unsigned. If the integer value fits in the lower end word of c,
- and if the higher end word has all its bits set to 1, that
- means the higher end bits are set to 1 only for sign extension.
- So let's convert c into an equivalent zero extended unsigned
- integer. */
- dc = double_int_zext (dc, TYPE_PRECISION (TREE_TYPE (c)));
-
retry:
type_low_bound = TYPE_MIN_VALUE (type);
type_high_bound = TYPE_MAX_VALUE (type);
--- 8109,8114 ----
*************** retry:
*** 8147,8156 ****
if (type_low_bound && TREE_CODE (type_low_bound) == INTEGER_CST)
{
dd = tree_to_double_int (type_low_bound);
- if (TREE_CODE (type) == INTEGER_TYPE
- && TYPE_IS_SIZETYPE (type)
- && TYPE_UNSIGNED (type))
- dd = double_int_zext (dd, TYPE_PRECISION (type));
if (unsc != TYPE_UNSIGNED (TREE_TYPE (type_low_bound)))
{
int c_neg = (!unsc && double_int_negative_p (dc));
--- 8127,8132 ----
*************** retry:
*** 8172,8181 ****
if (type_high_bound && TREE_CODE (type_high_bound) == INTEGER_CST)
{
dd = tree_to_double_int (type_high_bound);
- if (TREE_CODE (type) == INTEGER_TYPE
- && TYPE_IS_SIZETYPE (type)
- && TYPE_UNSIGNED (type))
- dd = double_int_zext (dd, TYPE_PRECISION (type));
if (unsc != TYPE_UNSIGNED (TREE_TYPE (type_high_bound)))
{
int c_neg = (!unsc && double_int_negative_p (dc));
--- 8148,8153 ----
Index: trunk/gcc/expr.c
===================================================================
*** trunk.orig/gcc/expr.c 2011-06-07 16:38:18.000000000 +0200
--- trunk/gcc/expr.c 2011-06-14 15:29:04.000000000 +0200
*************** get_inner_reference (tree exp, HOST_WIDE
*** 6137,6148 ****
/* If OFFSET is constant, see if we can return the whole thing as a
constant bit position. Make sure to handle overflow during
this conversion. */
! if (host_integerp (offset, 0))
{
! double_int tem = double_int_lshift (tree_to_double_int (offset),
! BITS_PER_UNIT == 8
! ? 3 : exact_log2 (BITS_PER_UNIT),
! HOST_BITS_PER_DOUBLE_INT, true);
tem = double_int_add (tem, bit_offset);
if (double_int_fits_in_shwi_p (tem))
{
--- 6137,6157 ----
/* If OFFSET is constant, see if we can return the whole thing as a
constant bit position. Make sure to handle overflow during
this conversion. */
! if (TREE_CODE (offset) == INTEGER_CST)
{
! double_int tem = tree_to_double_int (offset);
! /* Sign-extend the offset as HWI can have more precision
! than sizetype.
! ??? Alternatively we could truncate and sign-extend the final
! result to sizetype bit precision. But that is a functional
! change compared to the idea of tracking bit position with
! infinite precision (which isn't fulfilled already because of
! tracking the tree part in machine precision). */
! tem = double_int_sext (tem, TYPE_PRECISION (sizetype));
! tem = double_int_lshift (tem,
! BITS_PER_UNIT == 8
! ? 3 : exact_log2 (BITS_PER_UNIT),
! HOST_BITS_PER_DOUBLE_INT, true);
tem = double_int_add (tem, bit_offset);
if (double_int_fits_in_shwi_p (tem))
{
Index: trunk/gcc/tree-ssa-structalias.c
===================================================================
*** trunk.orig/gcc/tree-ssa-structalias.c 2011-06-14 14:26:14.000000000
+0200
--- trunk/gcc/tree-ssa-structalias.c 2011-06-14 15:29:04.000000000 +0200
*************** get_constraint_for_ptr_offset (tree ptr,
*** 2856,2862 ****
{
struct constraint_expr c;
unsigned int j, n;
! HOST_WIDE_INT rhsunitoffset, rhsoffset;
/* If we do not do field-sensitive PTA adding offsets to pointers
does not change the points-to solution. */
--- 2856,2862 ----
{
struct constraint_expr c;
unsigned int j, n;
! HOST_WIDE_INT rhsoffset;
/* If we do not do field-sensitive PTA adding offsets to pointers
does not change the points-to solution. */
*************** get_constraint_for_ptr_offset (tree ptr,
*** 2875,2882 ****
rhsoffset = UNKNOWN_OFFSET;
else
{
! /* Make sure the bit-offset also fits. */
! rhsunitoffset = TREE_INT_CST_LOW (offset);
rhsoffset = rhsunitoffset * BITS_PER_UNIT;
if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
rhsoffset = UNKNOWN_OFFSET;
--- 2875,2884 ----
rhsoffset = UNKNOWN_OFFSET;
else
{
! /* Sign-extend the unit offset and make sure the bit-offset also fits.
*/
! HOST_WIDE_INT rhsunitoffset
! = double_int_sext (tree_to_double_int (offset),
! TYPE_PRECISION (TREE_TYPE (offset))).low;
rhsoffset = rhsunitoffset * BITS_PER_UNIT;
if (rhsunitoffset != rhsoffset / BITS_PER_UNIT)
rhsoffset = UNKNOWN_OFFSET;
Index: trunk/gcc/tree-cfg.c
===================================================================
*** trunk.orig/gcc/tree-cfg.c 2011-06-08 16:45:50.000000000 +0200
--- trunk/gcc/tree-cfg.c 2011-06-14 15:29:04.000000000 +0200
*************** verify_types_in_gimple_reference (tree e
*** 3033,3039 ****
return true;
}
else if (TREE_CODE (op) == SSA_NAME
! && TYPE_SIZE (TREE_TYPE (expr)) != TYPE_SIZE (TREE_TYPE
(op)))
{
error ("conversion of register to a different size");
debug_generic_stmt (expr);
--- 3033,3040 ----
return true;
}
else if (TREE_CODE (op) == SSA_NAME
! && !tree_int_cst_equal (TYPE_SIZE (TREE_TYPE (expr)),
! TYPE_SIZE (TREE_TYPE (op))))
{
error ("conversion of register to a different size");
debug_generic_stmt (expr);
