Howdy!
Phew, I think this is the last abstraction. This handles the unary
CONVERT_EXPR_P code.
It's the usual story-- normalize the symbolics to [-MIN,+MAX] and handle
everything generically.
Normalizing the symbolics brought about some nice surprises. We now
handle a few things we were punting on before, which I've documented in
the patch, but can remove if so desired. I wrote them mainly for myself:
/* NOTES: Previously we were returning VARYING for all symbolics, but
we can do better by treating them as [-MIN, +MAX]. For
example, converting [SYM, SYM] from INT to LONG UNSIGNED,
we can return: ~[0x8000000, 0xffffffff7fffffff].
We were also failing to convert ~[0,0] from char* to unsigned,
instead choosing to return VR_VARYING. Now we return ~[0,0]. */
Tested on x86-64 by the usual bootstrap and regtest gymnastics,
including --enable-languages=all, because my past sins are still
haunting me.
OK?
gcc/
* wide-int-range.cc (wide_int_range_convert_tree): New.
* wide-int-range.h (wide_int_range_convert_tree): New.
* tree-vrp.c (extract_range_from_unary_expr): Abstract wide int
code into wide_int_range_convert_tree.
(extract_range_into_wide_ints): Do not munge anti range constants
into the entire domain. Just return the range back.
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index f20730a85ba..89fbbffcd2e 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -995,7 +995,7 @@ ranges_from_anti_range (value_range *ar,
/* 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
+ 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
@@ -1003,7 +1003,10 @@ extract_range_into_wide_ints (value_range *vr,
signop sign, unsigned prec,
wide_int &wmin, wide_int &wmax)
{
- if (range_int_cst_p (vr))
+ if ((vr->type == VR_RANGE
+ || vr->type == VR_ANTI_RANGE)
+ && TREE_CODE (vr->min) == INTEGER_CST
+ && TREE_CODE (vr->max) == INTEGER_CST)
{
wmin = wi::to_wide (vr->min);
wmax = wi::to_wide (vr->max);
@@ -1894,44 +1897,35 @@ extract_range_from_unary_expr (value_range *vr,
return;
}
- /* If VR0 is varying and we increase the type precision, assume
- a full range for the following transformation. */
- if (vr0.type == VR_VARYING
- && INTEGRAL_TYPE_P (inner_type)
- && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
- {
- vr0.type = VR_RANGE;
- vr0.min = TYPE_MIN_VALUE (inner_type);
- vr0.max = TYPE_MAX_VALUE (inner_type);
- }
-
- /* If VR0 is a constant range or anti-range and the conversion is
- not truncating we can convert the min and max values and
- canonicalize the resulting range. Otherwise we can do the
- conversion if the size of the range is less than what the
- precision of the target type can represent and the range is
- not an anti-range. */
- if ((vr0.type == VR_RANGE
- || vr0.type == VR_ANTI_RANGE)
+ /* We normalize everything to a VR_RANGE, but for constant
+ anti-ranges we must handle them by leaving the final result
+ as an anti range. This allows us to convert things like
+ ~[0,5] seamlessly. */
+ value_range_type vr_type = VR_RANGE;
+ if (vr0.type == VR_ANTI_RANGE
&& TREE_CODE (vr0.min) == INTEGER_CST
- && TREE_CODE (vr0.max) == INTEGER_CST
- && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
- || (vr0.type == VR_RANGE
- && integer_zerop (int_const_binop (RSHIFT_EXPR,
- int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
- size_int (TYPE_PRECISION (outer_type)))))))
- {
- tree new_min, new_max;
- new_min = force_fit_type (outer_type, wi::to_widest (vr0.min),
- 0, false);
- new_max = force_fit_type (outer_type, wi::to_widest (vr0.max),
- 0, false);
- set_and_canonicalize_value_range (vr, vr0.type,
- new_min, new_max, NULL);
- return;
- }
+ && TREE_CODE (vr0.max) == INTEGER_CST)
+ vr_type = VR_ANTI_RANGE;
- set_value_range_to_varying (vr);
+ /* NOTES: Previously we were returning VARYING for all symbolics, but
+ we can do better by treating them as [-MIN, +MAX]. For
+ example, converting [SYM, SYM] from INT to LONG UNSIGNED,
+ we can return: ~[0x8000000, 0xffffffff7fffffff].
+
+ We were also failing to convert ~[0,0] from char* to unsigned,
+ instead choosing to return VR_VARYING. Now we return ~[0,0]. */
+ wide_int vr0_min, vr0_max;
+ signop inner_sign = TYPE_SIGN (inner_type);
+ unsigned inner_prec = TYPE_PRECISION (inner_type);
+ tree tmin, tmax;
+ extract_range_into_wide_ints (&vr0, inner_sign, inner_prec,
+ vr0_min, vr0_max);
+ if (wide_int_range_convert_tree (tmin, tmax, outer_type,
+ inner_sign, inner_prec,
+ vr0_min, vr0_max))
+ set_and_canonicalize_value_range (vr, vr_type, tmin, tmax, NULL);
+ else
+ set_value_range_to_varying (vr);
return;
}
else if (code == ABS_EXPR)
diff --git a/gcc/wide-int-range.cc b/gcc/wide-int-range.cc
index 3cdcede04cd..d3e1424e77f 100644
--- a/gcc/wide-int-range.cc
+++ b/gcc/wide-int-range.cc
@@ -665,6 +665,42 @@ wide_int_range_abs (wide_int &min, wide_int &max,
return true;
}
+/* Convert range in VR0 to OUTER_TYPE and store the result in a pair of
+ trees [TMIN, TMAX].
+
+ Return TRUE if we were able to successfully calculate the new range.
+
+ Caller is responsible for canonicalizing the resulting range. */
+
+bool
+wide_int_range_convert_tree (tree &tmin, tree &tmax,
+ tree outer_type,
+ signop inner_sign,
+ unsigned inner_prec,
+ const wide_int &vr0_min,
+ const wide_int &vr0_max)
+{
+ /* If the conversion is not truncating we can convert the min and
+ max values and canonicalize the resulting range. Otherwise we
+ can do the conversion if the size of the range is less than what
+ the precision of the target type can represent. */
+ if (TYPE_PRECISION (outer_type) >= inner_prec
+ || wi::rshift (wi::sub (vr0_max, vr0_min),
+ wi::uhwi (TYPE_PRECISION (outer_type), inner_prec),
+ inner_sign) == 0)
+ {
+ signop outer_sign = TYPE_SIGN (outer_type);
+ outer_sign = inner_sign;
+ tmin = force_fit_type (outer_type,
+ widest_int::from (vr0_min, outer_sign), 0, false);
+ tmax = force_fit_type (outer_type,
+ widest_int::from (vr0_max, outer_sign), 0, false);
+ return (!operand_equal_p (tmin, TYPE_MIN_VALUE (outer_type), 0)
+ || !operand_equal_p (tmax, TYPE_MAX_VALUE (outer_type), 0));
+ }
+ return false;
+}
+
/* Calculate a division operation on two ranges and store the result in
[WMIN, WMAX] U [EXTRA_MIN, EXTRA_MAX].
diff --git a/gcc/wide-int-range.h b/gcc/wide-int-range.h
index 427ef34c6b4..6aa0b76b6e3 100644
--- a/gcc/wide-int-range.h
+++ b/gcc/wide-int-range.h
@@ -99,6 +99,12 @@ extern bool wide_int_range_abs (wide_int &min, wide_int &max,
const wide_int &vr0_min,
const wide_int &vr0_max,
bool overflow_undefined);
+extern bool wide_int_range_convert_tree (tree &tmin, tree &tmax,
+ tree outer_type,
+ signop inner_sign,
+ unsigned inner_prec,
+ const wide_int &vr0_min,
+ const wide_int &vr0_max);
extern bool wide_int_range_div (wide_int &wmin, wide_int &wmax,
enum tree_code code,
signop sign, unsigned prec,
