...well, most of them anyhow...
I got tired of submitting these piecemeal, and it's probably easier to
review them in one go.
There should be no difference in functionality, barring an extra call to
set_and_canonicalize_value_range (instead of set_value_range) due to the
way I've organized multiplication and lshifts for maximal sharing. This
also gets rid of some repetitive stuff.
I've also added a value_range::dump like wide_int::dump. It makes
debugging a lot easier.
My next patch will move all the wide_int_range_* stuff into
wide-int-range.[hc].
I'm really liking how this is turning out, BTW: a *lot* cleaner, less
code duplication, and shareable to boot :).
OK pending one more round of tests?
Aldy
gcc/
* tree-vrp (zero_nonzero_bits_from_bounds): Rename to...
(wide_int_set_zero_nonzero_bits): ...this.
(zero_nonzero_bits_from_vr): Rename to...
(vrp_set_zero_nonzero_bits): ...this.
(extract_range_from_multiplicative_op_1): Abstract wide int
code...
(wide_int_range_multiplicative_op): ...here.
(extract_range_from_binary_expr_1): Extract wide int binary
operations into their own functions.
(wide_int_range_lshift): New.
(wide_int_range_can_optimize_bit_op): New.
(wide_int_range_shift_undefined_p): New.
(wide_int_range_bit_xor): New.
(wide_int_range_bit_ior): New.
(wide_int_range_bit_and): New.
(wide_int_range_trunc_mod): New.
(extract_range_into_wide_ints): New.
(vrp_shift_undefined_p): New.
(extract_range_from_multiplicative_op): New.
(vrp_can_optimize_bit_op): New.
* tree-vrp.h (value_range::dump): New.
(wide_int_range_multiplicative_op): New.
(wide_int_range_lshift):New.
(wide_int_range_shift_undefined_p): New.
(wide_int_range_bit_xor): New.
(wide_int_range_bit_ior): New.
(wide_int_range_bit_and): New.
(wide_int_range_trunc_mod): New.
(zero_nonzero_bits_from_bounds): Rename to...
(wide_int_set_zero_nonzero_bits): ...this.
(zero_nonzero_bits_from_vr): Rename to...
(vrp_set_zero_nonzero_bits): ...this.
(range_easy_mask_min_max): Rename to...
(wide_int_range_can_optimize_bit_op): this.
* vr-values.c (simplify_bit_ops_using_ranges): Rename
zero_nonzero_bits_from_vr into vrp_set_zero_nonzero_bits.
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 7ab8898b453..619be7d07be 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -1008,45 +1008,54 @@ wide_int_binop_overflow (wide_int &res,
return !overflow;
}
-/* For range [LB, UB] compute two wide_int bitmasks. In *MAY_BE_NONZERO
- bitmask, if some bit is unset, it means for all numbers in the range
- the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
- bitmask, if some bit is set, it means for all numbers in the range
- the bit is 1, otherwise it might be 0 or 1. */
+/* For range [LB, UB] compute two wide_int bit masks.
+
+ In the MAY_BE_NONZERO bit mask, if some bit is unset, it means that
+ for all numbers in the range the bit is 0, otherwise it might be 0
+ or 1.
+
+ In the MUST_BE_NONZERO bit mask, if some bit is set, it means that
+ for all numbers in the range the bit is 1, otherwise it might be 0
+ or 1. */
void
-zero_nonzero_bits_from_bounds (signop sign,
- const wide_int &lb, const wide_int &ub,
- wide_int *may_be_nonzero,
- wide_int *must_be_nonzero)
+wide_int_set_zero_nonzero_bits (signop sign,
+ const wide_int &lb, const wide_int &ub,
+ wide_int &may_be_nonzero,
+ wide_int &must_be_nonzero)
{
- *may_be_nonzero = wi::minus_one (lb.get_precision ());
- *must_be_nonzero = wi::zero (lb.get_precision ());
+ may_be_nonzero = wi::minus_one (lb.get_precision ());
+ must_be_nonzero = wi::zero (lb.get_precision ());
if (wi::eq_p (lb, ub))
{
- *may_be_nonzero = lb;
- *must_be_nonzero = *may_be_nonzero;
+ may_be_nonzero = lb;
+ must_be_nonzero = may_be_nonzero;
}
else if (wi::ge_p (lb, 0, sign) || wi::lt_p (ub, 0, sign))
{
wide_int xor_mask = lb ^ ub;
- *may_be_nonzero = lb | ub;
- *must_be_nonzero = lb & ub;
+ may_be_nonzero = lb | ub;
+ must_be_nonzero = lb & ub;
if (xor_mask != 0)
{
wide_int mask = wi::mask (wi::floor_log2 (xor_mask), false,
- may_be_nonzero->get_precision ());
- *may_be_nonzero = *may_be_nonzero | mask;
- *must_be_nonzero = wi::bit_and_not (*must_be_nonzero, mask);
+ may_be_nonzero.get_precision ());
+ may_be_nonzero = may_be_nonzero | mask;
+ must_be_nonzero = wi::bit_and_not (must_be_nonzero, mask);
}
}
}
-/* Like zero_nonzero_bits_from_bounds, but use the range in value_range VR. */
+/* Value range wrapper for wide_int_set_zero_nonzero_bits.
+
+ Compute MAY_BE_NONZERO and MUST_BE_NONZERO bit masks for range in VR.
+
+ Return TRUE if VR was a constant range and we were able to compute
+ the bit masks. */
bool
-zero_nonzero_bits_from_vr (const tree expr_type,
+vrp_set_zero_nonzero_bits (const tree expr_type,
value_range *vr,
wide_int *may_be_nonzero,
wide_int *must_be_nonzero)
@@ -1057,10 +1066,9 @@ zero_nonzero_bits_from_vr (const tree expr_type,
*must_be_nonzero = wi::zero (TYPE_PRECISION (expr_type));
return false;
}
-
- zero_nonzero_bits_from_bounds (TYPE_SIGN (expr_type),
+ wide_int_set_zero_nonzero_bits (TYPE_SIGN (expr_type),
wi::to_wide (vr->min), wi::to_wide (vr->max),
- may_be_nonzero, must_be_nonzero);
+ *may_be_nonzero, *must_be_nonzero);
return true;
}
@@ -1177,7 +1185,9 @@ wide_int_range_cross_product (wide_int &res_lb, wide_int &res_ub,
[RES_LB, RES_UB] = [MIN0, MAX0] * [MIN1, MAX1]
This is basically fancy code so we don't drop to varying with an
- unsigned [-3,-1]*[-3,-1]. */
+ unsigned [-3,-1]*[-3,-1].
+
+ Return TRUE if we were able to perform the operation. */
bool
wide_int_range_mult_wrapping (wide_int &res_lb,
@@ -1249,13 +1259,27 @@ wide_int_range_mult_wrapping (wide_int &res_lb,
return true;
}
-/* Helper to extract a value-range *VR for a multiplicative operation
- *VR0 CODE *VR1. */
+/* Perform multiplicative operation CODE on two ranges:
-static void
-extract_range_from_multiplicative_op_1 (value_range *vr,
- enum tree_code code,
- value_range *vr0, value_range *vr1)
+ [RES_LB, RES_UB] = [VR0_LB, VR0_UB] .CODE. [VR1_LB, VR1_LB]
+
+ Return TRUE if we were able to perform the operation.
+
+ NOTE: If code is MULT_EXPR and TYPE_OVERFLOW_WRAPS, the resulting
+ range must be canonicalized by the caller because its components
+ may be swapped. */
+
+bool
+wide_int_range_multiplicative_op (wide_int &res_lb, wide_int &res_ub,
+ enum tree_code code,
+ signop sign,
+ unsigned prec,
+ const wide_int &vr0_lb,
+ const wide_int &vr0_ub,
+ const wide_int &vr1_lb,
+ const wide_int &vr1_ub,
+ bool overflow_undefined,
+ bool overflow_wraps)
{
/* Multiplications, divisions and shifts are a bit tricky to handle,
depending on the mix of signs we have in the two ranges, we
@@ -1269,62 +1293,131 @@ extract_range_from_multiplicative_op_1 (value_range *vr,
(MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
MAX1) and then figure the smallest and largest values to form
the new range. */
- gcc_assert (code == MULT_EXPR
- || code == TRUNC_DIV_EXPR
- || code == FLOOR_DIV_EXPR
- || code == CEIL_DIV_EXPR
- || code == EXACT_DIV_EXPR
- || code == ROUND_DIV_EXPR
- || code == RSHIFT_EXPR
- || code == LSHIFT_EXPR);
- gcc_assert (vr0->type == VR_RANGE
- && vr0->type == vr1->type);
+ if (code == MULT_EXPR && overflow_wraps)
+ return wide_int_range_mult_wrapping (res_lb, res_ub,
+ sign, prec,
+ vr0_lb, vr0_ub, vr1_lb, vr1_ub);
+ return wide_int_range_cross_product (res_lb, res_ub,
+ code, sign,
+ vr0_lb, vr0_ub, vr1_lb, vr1_ub,
+ overflow_undefined);
+}
- tree type = TREE_TYPE (vr0->min);
- wide_int res_lb, res_ub;
- wide_int vr0_lb = wi::to_wide (vr0->min);
- wide_int vr0_ub = wi::to_wide (vr0->max);
- wide_int vr1_lb = wi::to_wide (vr1->min);
- wide_int vr1_ub = wi::to_wide (vr1->max);
- bool overflow_undefined = TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr0->min));
+/* Perform a left shift operation on two ranges:
- if (!wide_int_range_cross_product (res_lb, res_ub,
- code, TYPE_SIGN (type),
- vr0_lb, vr0_ub, vr1_lb, vr1_ub,
- overflow_undefined))
+ [RES_LB, RES_UB] = [VR0_LB, VR0_UB] << [VR1_LB, VR1_LB]
+
+ Return TRUE if we were able to perform the operation.
+
+ NOTE: The resulting range must be canonicalized by the caller
+ because its contents components may be swapped. */
+
+bool
+wide_int_range_lshift (wide_int &res_lb, wide_int &res_ub,
+ signop sign, unsigned prec,
+ const wide_int &vr0_lb, const wide_int &vr0_ub,
+ const wide_int &vr1_lb, const wide_int &vr1_ub,
+ bool overflow_undefined, bool overflow_wraps)
+{
+ /* Transform left shifts by constants into multiplies. */
+ if (wi::eq_p (vr1_lb, vr1_ub))
{
- set_value_range_to_varying (vr);
- return;
+ int shift = wi::extract_uhwi (vr1_ub, 0, vr1_ub.get_precision ());
+ wide_int tmp = wi::set_bit_in_zero (shift, prec);
+ return wide_int_range_multiplicative_op (res_lb, res_ub,
+ MULT_EXPR, sign, prec,
+ vr0_lb, vr0_ub, tmp, tmp,
+ overflow_undefined,
+ /*overflow_wraps=*/true);
+ }
+
+ int overflow_pos = prec;
+ if (sign == SIGNED)
+ overflow_pos -= 1;
+ int bound_shift = overflow_pos - vr1_ub.to_shwi ();
+ /* If bound_shift == HOST_BITS_PER_WIDE_INT, the llshift can
+ overflow. However, for that to happen, vr1.max needs to be
+ zero, which means vr1 is a singleton range of zero, which
+ means it should be handled by the previous LSHIFT_EXPR
+ if-clause. */
+ wide_int bound = wi::set_bit_in_zero (bound_shift, prec);
+ wide_int complement = ~(bound - 1);
+ wide_int low_bound, high_bound;
+ bool in_bounds = false;
+ if (sign == UNSIGNED)
+ {
+ low_bound = bound;
+ high_bound = complement;
+ if (wi::ltu_p (vr0_ub, low_bound))
+ {
+ /* [5, 6] << [1, 2] == [10, 24]. */
+ /* We're shifting out only zeroes, the value increases
+ monotonically. */
+ in_bounds = true;
+ }
+ else if (wi::ltu_p (high_bound, vr0_lb))
+ {
+ /* [0xffffff00, 0xffffffff] << [1, 2]
+ == [0xfffffc00, 0xfffffffe]. */
+ /* We're shifting out only ones, the value decreases
+ monotonically. */
+ in_bounds = true;
+ }
}
- set_value_range (vr, VR_RANGE,
- wide_int_to_tree (type, res_lb),
- wide_int_to_tree (type, res_ub), NULL);
+ else
+ {
+ /* [-1, 1] << [1, 2] == [-4, 4]. */
+ low_bound = complement;
+ high_bound = bound;
+ if (wi::lts_p (vr0_ub, high_bound)
+ && wi::lts_p (low_bound, vr0_lb))
+ {
+ /* For non-negative numbers, we're shifting out only
+ zeroes, the value increases monotonically.
+ For negative numbers, we're shifting out only ones, the
+ value decreases monotomically. */
+ in_bounds = true;
+ }
+ }
+ if (in_bounds)
+ return wide_int_range_multiplicative_op (res_lb, res_ub,
+ LSHIFT_EXPR, sign, prec,
+ vr0_lb, vr0_ub,
+ vr1_lb, vr1_ub,
+ overflow_undefined,
+ overflow_wraps);
+ return false;
}
-/* For op & or | attempt to optimize:
+/* Return TRUE if a bit operation on two ranges can be easily
+ optimized in terms of a mask.
+
+ Basically, for BIT_AND_EXPR or BIT_IOR_EXPR see if we can optimize:
[LB, UB] op Z
into:
[LB op Z, UB op Z]
- if Z is a constant which (for op | its bitwise not) has n
- consecutive least significant bits cleared followed by m 1
- consecutive bits set immediately above it and either
- m + n == precision, or (x >> (m + n)) == (y >> (m + n)).
-
- The least significant n bits of all the values in the range are
- cleared or set, the m bits above it are preserved and any bits
- above these are required to be the same for all values in the
- range.
-
- Return TRUE if the min and max can simply be folded. */
+ It is up to the caller to perform the actual folding above. */
bool
-range_easy_mask_min_max (tree_code code,
- const wide_int &lb, const wide_int &ub,
- const wide_int &mask)
+wide_int_range_can_optimize_bit_op (tree_code code,
+ const wide_int &lb, const wide_int &ub,
+ const wide_int &mask)
{
+ if (code != BIT_AND_EXPR && code != BIT_IOR_EXPR)
+ return false;
+ /* If Z is a constant which (for op | its bitwise not) has n
+ consecutive least significant bits cleared followed by m 1
+ consecutive bits set immediately above it and either
+ m + n == precision, or (x >> (m + n)) == (y >> (m + n)).
+
+ The least significant n bits of all the values in the range are
+ cleared or set, the m bits above it are preserved and any bits
+ above these are required to be the same for all values in the
+ range. */
+
wide_int w = mask;
int m = 0, n = 0;
if (code == BIT_IOR_EXPR)
@@ -1347,6 +1440,308 @@ range_easy_mask_min_max (tree_code code,
return false;
}
+/* Return TRUE if shifting by range [MIN, MAX] is undefined behavior.
+
+ FIXME: Make this inline when it moves outside of tree-vrp. */
+
+bool
+wide_int_range_shift_undefined_p (signop sign, unsigned prec,
+ const wide_int &min, const wide_int &max)
+{
+ /* ?? Note: The original comment said this only applied to
+ RSHIFT_EXPR, but it was being applied to both left and right
+ shifts. Is this OK? */
+
+ /* Shifting by any values outside [0..prec-1], gets undefined
+ behavior from the shift operation. We cannot even trust
+ SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
+ shifts, and the operation at the tree level may be widened. */
+ return wi::lt_p (min, 0, sign) || wi::ge_p (max, prec, sign);
+}
+
+/* Calculate the XOR of two ranges and store the result in [WMIN,WMAX].
+ The two input ranges are described by their MUST_BE_NONZERO and
+ MAY_BE_NONZERO bit masks.
+
+ Return TRUE if we were able to successfully calculate the new range. */
+
+bool
+wide_int_range_bit_xor (wide_int &wmin, wide_int &wmax,
+ signop sign,
+ unsigned prec,
+ const wide_int &must_be_nonzero0,
+ const wide_int &may_be_nonzero0,
+ const wide_int &must_be_nonzero1,
+ const wide_int &may_be_nonzero1)
+{
+ wide_int result_zero_bits = ((must_be_nonzero0 & must_be_nonzero1)
+ | ~(may_be_nonzero0 | may_be_nonzero1));
+ wide_int result_one_bits
+ = (wi::bit_and_not (must_be_nonzero0, may_be_nonzero1)
+ | wi::bit_and_not (must_be_nonzero1, may_be_nonzero0));
+ wmax = ~result_zero_bits;
+ wmin = result_one_bits;
+ /* If the range has all positive or all negative values, the result
+ is better than VARYING. */
+ if (wi::lt_p (wmin, 0, sign) || wi::ge_p (wmax, 0, sign))
+ return true;
+ wmin = wi::min_value (prec, sign);
+ wmax = wi::max_value (prec, sign);
+ return false;
+}
+
+/* Calculate the IOR of two ranges and store the result in [WMIN,WMAX].
+ Return TRUE if we were able to successfully calculate the new range. */
+
+bool
+wide_int_range_bit_ior (wide_int &wmin, wide_int &wmax,
+ signop sign,
+ const wide_int &vr0_min,
+ const wide_int &vr0_max,
+ const wide_int &vr1_min,
+ const wide_int &vr1_max,
+ const wide_int &must_be_nonzero0,
+ const wide_int &may_be_nonzero0,
+ const wide_int &must_be_nonzero1,
+ const wide_int &may_be_nonzero1)
+{
+ wmin = must_be_nonzero0 | must_be_nonzero1;
+ wmax = may_be_nonzero0 | may_be_nonzero1;
+ /* If the input ranges contain only positive values we can
+ truncate the minimum of the result range to the maximum
+ of the input range minima. */
+ if (wi::ge_p (vr0_min, 0, sign)
+ && wi::ge_p (vr1_min, 0, sign))
+ {
+ wmin = wi::max (wmin, vr0_min, sign);
+ wmin = wi::max (wmin, vr1_min, sign);
+ }
+ /* If either input range contains only negative values
+ we can truncate the minimum of the result range to the
+ respective minimum range. */
+ if (wi::lt_p (vr0_max, 0, sign))
+ wmin = wi::max (wmin, vr0_min, sign);
+ if (wi::lt_p (vr1_max, 0, sign))
+ wmin = wi::max (wmin, vr1_min, sign);
+ /* If the limits got swapped around, indicate error so we can adjust
+ the range to VARYING. */
+ if (wi::gt_p (wmin, wmax,sign))
+ return false;
+ return true;
+}
+
+/* Calculate the bitwise AND of two ranges and store the result in [WMIN,WMAX].
+ Return TRUE if we were able to successfully calculate the new range. */
+
+bool
+wide_int_range_bit_and (wide_int &wmin, wide_int &wmax,
+ signop sign,
+ unsigned prec,
+ const wide_int &vr0_min,
+ const wide_int &vr0_max,
+ const wide_int &vr1_min,
+ const wide_int &vr1_max,
+ const wide_int &must_be_nonzero0,
+ const wide_int &may_be_nonzero0,
+ const wide_int &must_be_nonzero1,
+ const wide_int &may_be_nonzero1)
+{
+ wmin = must_be_nonzero0 & must_be_nonzero1;
+ wmax = may_be_nonzero0 & may_be_nonzero1;
+ /* If both input ranges contain only negative values we can
+ truncate the result range maximum to the minimum of the
+ input range maxima. */
+ if (wi::lt_p (vr0_max, 0, sign) && wi::lt_p (vr1_max, 0, sign))
+ {
+ wmax = wi::min (wmax, vr0_max, sign);
+ wmax = wi::min (wmax, vr1_max, sign);
+ }
+ /* If either input range contains only non-negative values
+ we can truncate the result range maximum to the respective
+ maximum of the input range. */
+ if (wi::ge_p (vr0_min, 0, sign))
+ wmax = wi::min (wmax, vr0_max, sign);
+ if (wi::ge_p (vr1_min, 0, sign))
+ wmax = wi::min (wmax, vr1_max, sign);
+ /* PR68217: In case of signed & sign-bit-CST should
+ result in [-INF, 0] instead of [-INF, INF]. */
+ if (wi::gt_p (wmin, wmax, sign))
+ {
+ wide_int sign_bit = wi::set_bit_in_zero (prec - 1, prec);
+ if (sign == SIGNED
+ && ((wi::eq_p (vr0_min, vr0_max)
+ && !wi::cmps (vr0_min, sign_bit))
+ || (wi::eq_p (vr1_min, vr1_max)
+ && !wi::cmps (vr1_min, sign_bit))))
+ {
+ wmin = wi::min_value (prec, sign);
+ wmax = wi::zero (prec);
+ }
+ }
+ /* If the limits got swapped around, indicate error so we can adjust
+ the range to VARYING. */
+ if (wi::gt_p (wmin, wmax,sign))
+ return false;
+ return true;
+}
+
+/* Calculate TRUNC_MOD_EXPR on two ranges and store the result in
+ [WMIN,WMAX]. */
+
+void
+wide_int_range_trunc_mod (wide_int &wmin, wide_int &wmax,
+ signop sign,
+ unsigned prec,
+ const wide_int &vr0_min,
+ const wide_int &vr0_max,
+ const wide_int &vr1_min,
+ const wide_int &vr1_max)
+{
+ wide_int tmp;
+
+ /* ABS (A % B) < ABS (B) and either
+ 0 <= A % B <= A or A <= A % B <= 0. */
+ wmax = vr1_max - 1;
+ if (sign == SIGNED)
+ {
+ tmp = -1 - vr1_min;
+ wmax = wi::smax (wmax, tmp);
+ }
+
+ if (sign == UNSIGNED)
+ wmin = wi::zero (prec);
+ else
+ {
+ wmin = -wmax;
+ tmp = vr0_min;
+ if (wi::gts_p (tmp, 0))
+ tmp = wi::zero (prec);
+ wmin = wi::smax (wmin, tmp);
+ }
+ tmp = vr0_max;
+ if (sign == SIGNED && wi::neg_p (tmp))
+ tmp = wi::zero (prec);
+ wmax = wi::min (wmax, tmp, sign);
+}
+
+/* Extract the components of a value range into a pair of wide ints in
+ [WMIN, WMAX].
+
+ If the value range is anything but a VR_RANGE of constants, the
+ resulting wide ints are set to [-MIN, +MAX] for the type. */
+
+static void inline
+extract_range_into_wide_ints (value_range *vr,
+ signop sign, unsigned prec,
+ wide_int *wmin, wide_int *wmax)
+{
+ if (range_int_cst_p (vr))
+ {
+ *wmin = wi::to_wide (vr->min);
+ *wmax = wi::to_wide (vr->max);
+ }
+ else
+ {
+ *wmin = wi::min_value (prec, sign);
+ *wmax = wi::max_value (prec, sign);
+ }
+}
+
+/* Value range wrapper for wide_int_range_shift_undefined_p. */
+
+static inline bool
+vrp_shift_undefined_p (const value_range &shifter)
+{
+ tree type = TREE_TYPE (shifter.min);
+ return wide_int_range_shift_undefined_p (TYPE_SIGN (type),
+ TYPE_PRECISION (type),
+ wi::to_wide (shifter.min),
+ wi::to_wide (shifter.max));
+}
+
+/* Value range wrapper for wide_int_range_multiplicative_op:
+
+ *VR = *VR0 .CODE. *VR1. */
+
+static void
+extract_range_from_multiplicative_op (value_range *vr,
+ enum tree_code code,
+ value_range *vr0, value_range *vr1)
+{
+ gcc_assert (code == MULT_EXPR
+ || code == TRUNC_DIV_EXPR
+ || code == FLOOR_DIV_EXPR
+ || code == CEIL_DIV_EXPR
+ || code == EXACT_DIV_EXPR
+ || code == ROUND_DIV_EXPR
+ || code == RSHIFT_EXPR
+ || code == LSHIFT_EXPR);
+ gcc_assert (vr0->type == VR_RANGE && vr0->type == vr1->type);
+
+ tree type = TREE_TYPE (vr0->min);
+ wide_int res_lb, res_ub;
+ wide_int vr0_lb = wi::to_wide (vr0->min);
+ wide_int vr0_ub = wi::to_wide (vr0->max);
+ wide_int vr1_lb = wi::to_wide (vr1->min);
+ wide_int vr1_ub = wi::to_wide (vr1->max);
+ bool overflow_undefined = TYPE_OVERFLOW_UNDEFINED (type);
+ bool overflow_wraps = TYPE_OVERFLOW_WRAPS (type);
+ unsigned prec = TYPE_PRECISION (type);
+
+ if (wide_int_range_multiplicative_op (res_lb, res_ub,
+ code, TYPE_SIGN (type), prec,
+ vr0_lb, vr0_ub, vr1_lb, vr1_ub,
+ overflow_undefined, overflow_wraps))
+ set_and_canonicalize_value_range (vr, VR_RANGE,
+ wide_int_to_tree (type, res_lb),
+ wide_int_to_tree (type, res_ub), NULL);
+ else
+ set_value_range_to_varying (vr);
+}
+
+/* Value range wrapper for wide_int_range_can_optimize_bit_op.
+
+ If a bit operation on two ranges can be easily optimized in terms
+ of a mask, store the optimized new range in VR and return TRUE. */
+
+static bool
+vrp_can_optimize_bit_op (value_range *vr, enum tree_code code,
+ value_range *vr0, value_range *vr1)
+{
+ tree lower_bound, upper_bound, mask;
+ if (code != BIT_AND_EXPR && code != BIT_IOR_EXPR)
+ return false;
+ if (range_int_cst_singleton_p (vr1))
+ {
+ if (!range_int_cst_p (vr0))
+ return false;
+ mask = vr1->min;
+ lower_bound = vr0->min;
+ upper_bound = vr0->max;
+ }
+ else if (range_int_cst_singleton_p (vr0))
+ {
+ if (!range_int_cst_p (vr1))
+ return false;
+ mask = vr0->min;
+ lower_bound = vr1->min;
+ upper_bound = vr1->max;
+ }
+ else
+ return false;
+ if (wide_int_range_can_optimize_bit_op (code,
+ wi::to_wide (lower_bound),
+ wi::to_wide (upper_bound),
+ wi::to_wide (mask)))
+ {
+ tree min = int_const_binop (code, lower_bound, mask);
+ tree max = int_const_binop (code, upper_bound, mask);
+ set_value_range (vr, VR_RANGE, min, max, NULL);
+ return true;
+ }
+ return false;
+}
+
/* If BOUND will include a symbolic bound, adjust it accordingly,
otherwise leave it as is.
@@ -1522,6 +1917,8 @@ extract_range_from_binary_expr_1 (value_range *vr,
enum tree_code code, tree expr_type,
value_range *vr0_, value_range *vr1_)
{
+ signop sign = TYPE_SIGN (expr_type);
+ unsigned int prec = TYPE_PRECISION (expr_type);
value_range vr0 = *vr0_, vr1 = *vr1_;
value_range vrtem0 = VR_INITIALIZER, vrtem1 = VR_INITIALIZER;
enum value_range_type type;
@@ -1845,40 +2242,14 @@ extract_range_from_binary_expr_1 (value_range *vr,
set_value_range_to_varying (vr);
return;
}
- if (TYPE_OVERFLOW_WRAPS (expr_type))
- {
- signop sign = TYPE_SIGN (expr_type);
- unsigned int prec = TYPE_PRECISION (expr_type);
- wide_int res_lb, res_ub;
- if (!wide_int_range_mult_wrapping (res_lb, res_ub,
- sign, prec,
- wi::to_wide (vr0.min),
- wi::to_wide (vr0.max),
- wi::to_wide (vr1.min),
- wi::to_wide (vr1.max)))
- {
- set_value_range_to_varying (vr);
- return;
- }
- min = wide_int_to_tree (expr_type, res_lb);
- max = wide_int_to_tree (expr_type, res_ub);
- set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
- return;
- }
- extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
+ extract_range_from_multiplicative_op (vr, code, &vr0, &vr1);
return;
}
else if (code == RSHIFT_EXPR
|| code == LSHIFT_EXPR)
{
- /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
- then drop to VR_VARYING. Outside of this range we get undefined
- behavior from the shift operation. We cannot even trust
- SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
- shifts, and the operation at the tree level may be widened. */
if (range_int_cst_p (&vr1)
- && compare_tree_int (vr1.min, 0) >= 0
- && compare_tree_int (vr1.max, TYPE_PRECISION (expr_type)) == -1)
+ && !vrp_shift_undefined_p (vr1))
{
if (code == RSHIFT_EXPR)
{
@@ -1891,91 +2262,25 @@ extract_range_from_binary_expr_1 (value_range *vr,
vr0.min = vrp_val_min (expr_type);
vr0.max = vrp_val_max (expr_type);
}
- extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
- return;
- }
- /* We can map lshifts by constants to MULT_EXPR handling. */
- else if (code == LSHIFT_EXPR
- && range_int_cst_singleton_p (&vr1))
- {
- bool saved_flag_wrapv;
- value_range vr1p = VR_INITIALIZER;
- vr1p.type = VR_RANGE;
- vr1p.min = (wide_int_to_tree
- (expr_type,
- wi::set_bit_in_zero (tree_to_shwi (vr1.min),
- TYPE_PRECISION (expr_type))));
- vr1p.max = vr1p.min;
- /* We have to use a wrapping multiply though as signed overflow
- on lshifts is implementation defined in C89. */
- saved_flag_wrapv = flag_wrapv;
- flag_wrapv = 1;
- extract_range_from_binary_expr_1 (vr, MULT_EXPR, expr_type,
- &vr0, &vr1p);
- flag_wrapv = saved_flag_wrapv;
+ extract_range_from_multiplicative_op (vr, code, &vr0, &vr1);
return;
}
else if (code == LSHIFT_EXPR
&& range_int_cst_p (&vr0))
{
- int prec = TYPE_PRECISION (expr_type);
- int overflow_pos = prec;
- int bound_shift;
- wide_int low_bound, high_bound;
- bool uns = TYPE_UNSIGNED (expr_type);
- bool in_bounds = false;
-
- if (!uns)
- overflow_pos -= 1;
-
- bound_shift = overflow_pos - tree_to_shwi (vr1.max);
- /* If bound_shift == HOST_BITS_PER_WIDE_INT, the llshift can
- overflow. However, for that to happen, vr1.max needs to be
- zero, which means vr1 is a singleton range of zero, which
- means it should be handled by the previous LSHIFT_EXPR
- if-clause. */
- wide_int bound = wi::set_bit_in_zero (bound_shift, prec);
- wide_int complement = ~(bound - 1);
-
- if (uns)
- {
- low_bound = bound;
- high_bound = complement;
- if (wi::ltu_p (wi::to_wide (vr0.max), low_bound))
- {
- /* [5, 6] << [1, 2] == [10, 24]. */
- /* We're shifting out only zeroes, the value increases
- monotonically. */
- in_bounds = true;
- }
- else if (wi::ltu_p (high_bound, wi::to_wide (vr0.min)))
- {
- /* [0xffffff00, 0xffffffff] << [1, 2]
- == [0xfffffc00, 0xfffffffe]. */
- /* We're shifting out only ones, the value decreases
- monotonically. */
- in_bounds = true;
- }
- }
- else
- {
- /* [-1, 1] << [1, 2] == [-4, 4]. */
- low_bound = complement;
- high_bound = bound;
- if (wi::lts_p (wi::to_wide (vr0.max), high_bound)
- && wi::lts_p (low_bound, wi::to_wide (vr0.min)))
- {
- /* For non-negative numbers, we're shifting out only
- zeroes, the value increases monotonically.
- For negative numbers, we're shifting out only ones, the
- value decreases monotomically. */
- in_bounds = true;
- }
- }
-
- if (in_bounds)
+ wide_int res_lb, res_ub;
+ if (wide_int_range_lshift (res_lb, res_ub, sign, prec,
+ wi::to_wide (vr0.min),
+ wi::to_wide (vr0.max),
+ wi::to_wide (vr1.min),
+ wi::to_wide (vr1.max),
+ TYPE_OVERFLOW_UNDEFINED (expr_type),
+ TYPE_OVERFLOW_WRAPS (expr_type)))
{
- extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
+ min = wide_int_to_tree (expr_type, res_lb);
+ max = wide_int_to_tree (expr_type, res_ub);
+ set_and_canonicalize_value_range (vr, VR_RANGE,
+ min, max, NULL);
return;
}
}
@@ -2089,7 +2394,7 @@ extract_range_from_binary_expr_1 (value_range *vr,
}
else if (range_int_cst_p (&vr0) && range_int_cst_p (&vr1))
{
- extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
+ extract_range_from_multiplicative_op (vr, code, &vr0, &vr1);
return;
}
}
@@ -2100,187 +2405,83 @@ extract_range_from_binary_expr_1 (value_range *vr,
set_value_range_to_undefined (vr);
return;
}
- /* ABS (A % B) < ABS (B) and either
- 0 <= A % B <= A or A <= A % B <= 0. */
- type = VR_RANGE;
- signop sgn = TYPE_SIGN (expr_type);
- unsigned int prec = TYPE_PRECISION (expr_type);
wide_int wmin, wmax, tmp;
- if (vr1.type == VR_RANGE && !symbolic_range_p (&vr1))
- {
- wmax = wi::to_wide (vr1.max) - 1;
- if (sgn == SIGNED)
- {
- tmp = -1 - wi::to_wide (vr1.min);
- wmax = wi::smax (wmax, tmp);
- }
- }
- else
- {
- wmax = wi::max_value (prec, sgn);
- /* X % INT_MIN may be INT_MAX. */
- if (sgn == UNSIGNED)
- wmax = wmax - 1;
- }
-
- if (sgn == UNSIGNED)
- wmin = wi::zero (prec);
- else
- {
- wmin = -wmax;
- if (vr0.type == VR_RANGE && TREE_CODE (vr0.min) == INTEGER_CST)
- {
- tmp = wi::to_wide (vr0.min);
- if (wi::gts_p (tmp, 0))
- tmp = wi::zero (prec);
- wmin = wi::smax (wmin, tmp);
- }
- }
-
- if (vr0.type == VR_RANGE && TREE_CODE (vr0.max) == INTEGER_CST)
- {
- tmp = wi::to_wide (vr0.max);
- if (sgn == SIGNED && wi::neg_p (tmp))
- tmp = wi::zero (prec);
- wmax = wi::min (wmax, tmp, sgn);
- }
-
+ wide_int vr0_min, vr0_max, vr1_min, vr1_max;
+ extract_range_into_wide_ints (&vr0, sign, prec, &vr0_min, &vr0_max);
+ extract_range_into_wide_ints (&vr1, sign, prec, &vr1_min, &vr1_max);
+ wide_int_range_trunc_mod (wmin, wmax, sign, prec,
+ vr0_min, vr0_max, vr1_min, vr1_max);
min = wide_int_to_tree (expr_type, wmin);
max = wide_int_to_tree (expr_type, wmax);
+ set_value_range (vr, VR_RANGE, min, max, NULL);
+ return;
}
else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR)
{
- bool int_cst_range0, int_cst_range1;
+ if (vrp_can_optimize_bit_op (vr, code, &vr0, &vr1))
+ return;
+
wide_int may_be_nonzero0, may_be_nonzero1;
wide_int must_be_nonzero0, must_be_nonzero1;
-
- int_cst_range0 = zero_nonzero_bits_from_vr (expr_type, &vr0,
- &may_be_nonzero0,
- &must_be_nonzero0);
- int_cst_range1 = zero_nonzero_bits_from_vr (expr_type, &vr1,
- &may_be_nonzero1,
- &must_be_nonzero1);
-
- if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
- {
- value_range *vr0p = NULL, *vr1p = NULL;
- if (range_int_cst_singleton_p (&vr1))
- {
- vr0p = &vr0;
- vr1p = &vr1;
- }
- else if (range_int_cst_singleton_p (&vr0))
+ wide_int wmin, wmax;
+ wide_int vr0_min, vr0_max, vr1_min, vr1_max;
+ vrp_set_zero_nonzero_bits (expr_type, &vr0,
+ &may_be_nonzero0, &must_be_nonzero0);
+ vrp_set_zero_nonzero_bits (expr_type, &vr1,
+ &may_be_nonzero1, &must_be_nonzero1);
+ extract_range_into_wide_ints (&vr0, sign, prec, &vr0_min, &vr0_max);
+ extract_range_into_wide_ints (&vr1, sign, prec, &vr1_min, &vr1_max);
+ if (code == BIT_AND_EXPR)
+ {
+ if (wide_int_range_bit_and (wmin, wmax, sign, prec,
+ vr0_min, vr0_max,
+ vr1_min, vr1_max,
+ must_be_nonzero0,
+ may_be_nonzero0,
+ must_be_nonzero1,
+ may_be_nonzero1))
{
- vr0p = &vr1;
- vr1p = &vr0;
- }
- /* For op & or | attempt to optimize:
- [x, y] op z into [x op z, y op z]. */
- if (vr0p && range_int_cst_p (vr0p)
- && range_easy_mask_min_max (code, wi::to_wide (vr0p->min),
- wi::to_wide (vr0p->max),
- wi::to_wide (vr1p->min)))
- {
- min = int_const_binop (code, vr0p->min, vr1p->min);
- max = int_const_binop (code, vr0p->max, vr1p->min);
- }
- }
-
- type = VR_RANGE;
- if (min && max)
- /* Optimized above already. */;
- else if (code == BIT_AND_EXPR)
- {
- min = wide_int_to_tree (expr_type,
- must_be_nonzero0 & must_be_nonzero1);
- wide_int wmax = may_be_nonzero0 & may_be_nonzero1;
- /* If both input ranges contain only negative values we can
- truncate the result range maximum to the minimum of the
- input range maxima. */
- if (int_cst_range0 && int_cst_range1
- && tree_int_cst_sgn (vr0.max) < 0
- && tree_int_cst_sgn (vr1.max) < 0)
- {
- wmax = wi::min (wmax, wi::to_wide (vr0.max),
- TYPE_SIGN (expr_type));
- wmax = wi::min (wmax, wi::to_wide (vr1.max),
- TYPE_SIGN (expr_type));
- }
- /* If either input range contains only non-negative values
- we can truncate the result range maximum to the respective
- maximum of the input range. */
- if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
- wmax = wi::min (wmax, wi::to_wide (vr0.max),
- TYPE_SIGN (expr_type));
- if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
- wmax = wi::min (wmax, wi::to_wide (vr1.max),
- TYPE_SIGN (expr_type));
- max = wide_int_to_tree (expr_type, wmax);
- cmp = compare_values (min, max);
- /* PR68217: In case of signed & sign-bit-CST should
- result in [-INF, 0] instead of [-INF, INF]. */
- if (cmp == -2 || cmp == 1)
- {
- wide_int sign_bit
- = wi::set_bit_in_zero (TYPE_PRECISION (expr_type) - 1,
- TYPE_PRECISION (expr_type));
- if (!TYPE_UNSIGNED (expr_type)
- && ((int_cst_range0
- && value_range_constant_singleton (&vr0)
- && !wi::cmps (wi::to_wide (vr0.min), sign_bit))
- || (int_cst_range1
- && value_range_constant_singleton (&vr1)
- && !wi::cmps (wi::to_wide (vr1.min), sign_bit))))
- {
- min = TYPE_MIN_VALUE (expr_type);
- max = build_int_cst (expr_type, 0);
- }
+ min = wide_int_to_tree (expr_type, wmin);
+ max = wide_int_to_tree (expr_type, wmax);
+ set_value_range (vr, VR_RANGE, min, max, NULL);
}
+ else
+ set_value_range_to_varying (vr);
+ return;
}
else if (code == BIT_IOR_EXPR)
{
- max = wide_int_to_tree (expr_type,
- may_be_nonzero0 | may_be_nonzero1);
- wide_int wmin = must_be_nonzero0 | must_be_nonzero1;
- /* If the input ranges contain only positive values we can
- truncate the minimum of the result range to the maximum
- of the input range minima. */
- if (int_cst_range0 && int_cst_range1
- && tree_int_cst_sgn (vr0.min) >= 0
- && tree_int_cst_sgn (vr1.min) >= 0)
+ if (wide_int_range_bit_ior (wmin, wmax, sign,
+ vr0_min, vr0_max,
+ vr1_min, vr1_max,
+ must_be_nonzero0,
+ may_be_nonzero0,
+ must_be_nonzero1,
+ may_be_nonzero1))
{
- wmin = wi::max (wmin, wi::to_wide (vr0.min),
- TYPE_SIGN (expr_type));
- wmin = wi::max (wmin, wi::to_wide (vr1.min),
- TYPE_SIGN (expr_type));
+ min = wide_int_to_tree (expr_type, wmin);
+ max = wide_int_to_tree (expr_type, wmax);
+ set_value_range (vr, VR_RANGE, min, max, NULL);
}
- /* If either input range contains only negative values
- we can truncate the minimum of the result range to the
- respective minimum range. */
- if (int_cst_range0 && tree_int_cst_sgn (vr0.max) < 0)
- wmin = wi::max (wmin, wi::to_wide (vr0.min),
- TYPE_SIGN (expr_type));
- if (int_cst_range1 && tree_int_cst_sgn (vr1.max) < 0)
- wmin = wi::max (wmin, wi::to_wide (vr1.min),
- TYPE_SIGN (expr_type));
- min = wide_int_to_tree (expr_type, wmin);
+ else
+ set_value_range_to_varying (vr);
+ return;
}
else if (code == BIT_XOR_EXPR)
{
- wide_int result_zero_bits = ((must_be_nonzero0 & must_be_nonzero1)
- | ~(may_be_nonzero0 | may_be_nonzero1));
- wide_int result_one_bits
- = (wi::bit_and_not (must_be_nonzero0, may_be_nonzero1)
- | wi::bit_and_not (must_be_nonzero1, may_be_nonzero0));
- max = wide_int_to_tree (expr_type, ~result_zero_bits);
- min = wide_int_to_tree (expr_type, result_one_bits);
- /* If the range has all positive or all negative values the
- result is better than VARYING. */
- if (tree_int_cst_sgn (min) < 0
- || tree_int_cst_sgn (max) >= 0)
- ;
+ if (wide_int_range_bit_xor (wmin, wmax, sign, prec,
+ must_be_nonzero0,
+ may_be_nonzero0,
+ must_be_nonzero1,
+ may_be_nonzero1))
+ {
+ min = wide_int_to_tree (expr_type, wmin);
+ max = wide_int_to_tree (expr_type, wmax);
+ set_value_range (vr, VR_RANGE, min, max, NULL);
+ }
else
- max = min = NULL_TREE;
+ set_value_range_to_varying (vr);
+ return;
}
}
else
@@ -2608,6 +2809,12 @@ debug_value_range (value_range *vr)
fprintf (stderr, "\n");
}
+void
+value_range::dump ()
+{
+ debug_value_range (this);
+}
+
/* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
create a new SSA name N and return the assertion assignment
diff --git a/gcc/tree-vrp.h b/gcc/tree-vrp.h
index daf12ce31d1..8cac7daada7 100644
--- a/gcc/tree-vrp.h
+++ b/gcc/tree-vrp.h
@@ -49,6 +49,9 @@ struct GTY((for_user)) value_range
/* Set of SSA names whose value ranges are equivalent to this one.
This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
bitmap equiv;
+
+ /* Dump value range to stderr. */
+ void dump ();
};
extern void vrp_intersect_ranges (value_range *vr0, value_range *vr1);
@@ -115,6 +118,70 @@ extern bool wide_int_range_mult_wrapping (wide_int &res_lb,
const wide_int &max0_,
const wide_int &min1_,
const wide_int &max1_);
+extern bool wide_int_range_multiplicative_op (wide_int &res_lb,
+ wide_int &res_ub,
+ enum tree_code code,
+ signop sign,
+ unsigned prec,
+ const wide_int &vr0_lb,
+ const wide_int &vr0_ub,
+ const wide_int &vr1_lb,
+ const wide_int &vr1_ub,
+ bool overflow_undefined,
+ bool overflow_wraps);
+extern bool wide_int_range_lshift (wide_int &res_lb, wide_int &res_ub,
+ signop sign, unsigned prec,
+ const wide_int &, const wide_int &,
+ const wide_int &, const wide_int &,
+ bool overflow_undefined,
+ bool overflow_wraps);
+extern bool wide_int_range_shift_undefined_p (signop sign, unsigned prec,
+ const wide_int &min,
+ const wide_int &max);
+extern void wide_int_set_zero_nonzero_bits (signop,
+ const wide_int &lb,
+ const wide_int &ub,
+ wide_int &may_be_nonzero,
+ wide_int &must_be_nonzero);
+extern bool wide_int_range_can_optimize_bit_op (tree_code,
+ const wide_int &lb,
+ const wide_int &ub,
+ const wide_int &mask);
+extern bool wide_int_range_bit_xor (wide_int &wmin, wide_int &wmax,
+ signop sign,
+ unsigned prec,
+ const wide_int &must_be_nonzero0,
+ const wide_int &may_be_nonzero0,
+ const wide_int &must_be_nonzero1,
+ const wide_int &may_be_nonzero1);
+extern bool wide_int_range_bit_ior (wide_int &wmin, wide_int &wmax,
+ signop sign,
+ const wide_int &vr0_min,
+ const wide_int &vr0_max,
+ const wide_int &vr1_min,
+ const wide_int &vr1_max,
+ const wide_int &must_be_nonzero0,
+ const wide_int &may_be_nonzero0,
+ const wide_int &must_be_nonzero1,
+ const wide_int &may_be_nonzero1);
+extern bool wide_int_range_bit_and (wide_int &wmin, wide_int &wmax,
+ signop sign,
+ unsigned prec,
+ const wide_int &vr0_min,
+ const wide_int &vr0_max,
+ const wide_int &vr1_min,
+ const wide_int &vr1_max,
+ const wide_int &must_be_nonzero0,
+ const wide_int &may_be_nonzero0,
+ const wide_int &must_be_nonzero1,
+ const wide_int &may_be_nonzero1);
+extern void wide_int_range_trunc_mod (wide_int &wmin, wide_int &wmax,
+ signop sign,
+ unsigned prec,
+ const wide_int &vr0_min,
+ const wide_int &vr0_max,
+ const wide_int &vr1_min,
+ const wide_int &vr1_max);
extern void extract_range_from_binary_expr_1 (value_range *, enum tree_code,
tree, value_range *,
value_range *);
@@ -125,14 +192,8 @@ extern bool range_int_cst_p (value_range *);
extern int operand_less_p (tree, tree);
extern bool find_case_label_range (gswitch *, tree, tree, size_t *, size_t *);
extern bool find_case_label_index (gswitch *, size_t, tree, size_t *);
-extern void zero_nonzero_bits_from_bounds (signop, const wide_int&,
- const wide_int&, wide_int *,
- wide_int *);
-extern bool zero_nonzero_bits_from_vr (const tree, value_range *,
+extern bool vrp_set_zero_nonzero_bits (const tree, value_range *,
wide_int *, wide_int *);
-extern bool range_easy_mask_min_max (tree_code,
- const wide_int &lb, const wide_int &ub,
- const wide_int &mask);
extern bool overflow_comparison_p (tree_code, tree, tree, bool, tree *);
extern bool range_int_cst_singleton_p (value_range *);
extern int value_inside_range (tree, tree, tree);
diff --git a/gcc/vr-values.c b/gcc/vr-values.c
index bba170f341b..33335f3da31 100644
--- a/gcc/vr-values.c
+++ b/gcc/vr-values.c
@@ -3300,10 +3300,10 @@ vr_values::simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi,
else
return false;
- if (!zero_nonzero_bits_from_vr (TREE_TYPE (op0), &vr0, &may_be_nonzero0,
+ if (!vrp_set_zero_nonzero_bits (TREE_TYPE (op0), &vr0, &may_be_nonzero0,
&must_be_nonzero0))
return false;
- if (!zero_nonzero_bits_from_vr (TREE_TYPE (op1), &vr1, &may_be_nonzero1,
+ if (!vrp_set_zero_nonzero_bits (TREE_TYPE (op1), &vr1, &may_be_nonzero1,
&must_be_nonzero1))
return false;
