* [COMMITTED] Integrate nonzero bits with irange.
@ 2022-07-04 9:34 Aldy Hernandez
0 siblings, 0 replies; only message in thread
From: Aldy Hernandez @ 2022-07-04 9:34 UTC (permalink / raw)
To: GCC patches
The nonzero bits and integer ranges compliment each other quite well,
and it only makes sense to make the mask a first class citizen in the
irange. We do a half assed job of keeping ranges and nonzero bits
somewhat in sync in SSA_NAME_RANGE_INFO, and the goal has always
been to integrate them properly. This patch does that, in preparation
for streaming out full-resolution iranges between passes (think
SSA_NAME_RANGE_INFO).
Having nonzero bits in the irange allows us to get better results from
things like irange::contains_p() and keeping them in the irange allows
us to propagate the bits throughout with the ranger. This patch
provides the bare infrastructure, without any optimizations to
range-ops, etc. Those will come as follow-ups.
A few notes:
Legacy SSA_NAME_RANGE_INFO updates the nonzero bits every time a range
is set. Here instead, we don't update the nonzero bits on a new
range, but calculate it on the fly when irange::get_nonzero_bits() is
called. The goal is to only store nonzero bits that provide
meaningful information that can't be gleaned from the range itself.
But you can always call get_nonzero_bits() and get the full
information.
Nonzero bits are not supported in legacy mode. The mask may be set
as a consequence of propagation or reading global ranges, but no
one from legacy land should be querying irange::get_nonzero_bits. There
is an assert enforcing this. However, legacy/global set_nonzero_bits()
continue to work as before. There is no change to legacy behavior.
There is virtually no performance change with this patch, as there are
no consumers. The next patch I post will be the SSA_NAME_RANGE_INFO
conversion to the new world, in which I will discuss performance
proper. Hint: I'll be chewing up the time budget we gained with the
vrange conversion.
Tested and benchmarked on x86-64 Linux.
gcc/ChangeLog:
* value-range-storage.cc (irange_storage_slot::set_irange): Set
nonzero bits in irange.
(irange_storage_slot::get_irange): Get nonzero bits from irange.
* value-range.cc (irange::operator=): Set nonzero bits.
(irange::irange_set): Same.
(irange::irange_set_anti_range): Same.
(irange::set): Same.
(irange::verify_range): Same.
(irange::legacy_equal_p): Check nonzero bits.
(irange::equal_p): Same.
(irange::contains_p): Handle nonzero bits.
(irange::irange_union): Same.
(irange::irange_intersect): Same.
(irange::dump): Same.
(irange::set_nonzero_bits): New.
(irange::get_nonzero_bits): New.
(irange::intersect_nonzero_bits): New.
(irange::union_nonzero_bits): New.
(irange::dump_bitmasks): New.
* value-range.h (class irange): Add m_nonzero_mask.
(gt_ggc_mx): Handle nonzero bits.
(gt_pch_nx): Same.
(irange::set_undefined): Set nonzero bits.
(irange::set_varying): Same.
(irange::normalize_kind): Call set_undefined.
---
gcc/value-range-storage.cc | 9 +-
gcc/value-range.cc | 177 ++++++++++++++++++++++++++++++++++---
gcc/value-range.h | 20 ++++-
3 files changed, 193 insertions(+), 13 deletions(-)
diff --git a/gcc/value-range-storage.cc b/gcc/value-range-storage.cc
index ea9b18f993b..ac62bfaa638 100644
--- a/gcc/value-range-storage.cc
+++ b/gcc/value-range-storage.cc
@@ -131,7 +131,12 @@ irange_storage_slot::set_irange (const irange &r)
{
gcc_checking_assert (fits_p (r));
- //m_ints[0] = r.get_nonzero_bits ();
+ // Avoid calling unsupported get_nonzero_bits on legacy.
+ if (r.legacy_mode_p ())
+ m_ints[0] = -1;
+ else
+ m_ints[0] = r.get_nonzero_bits ();
+
unsigned pairs = r.num_pairs ();
for (unsigned i = 0; i < pairs; ++i)
{
@@ -154,7 +159,7 @@ irange_storage_slot::get_irange (irange &r, tree type) const
int_range<2> tmp (type, m_ints[i], m_ints[i + 1]);
r.union_ (tmp);
}
- //r.set_nonzero_bits (get_nonzero_bits ());
+ r.set_nonzero_bits (get_nonzero_bits ());
}
// Return the size in bytes to allocate a slot that can hold R.
diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index 574c51002b5..25f1acff4a3 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -274,6 +274,7 @@ irange::operator= (const irange &src)
m_num_ranges = lim;
m_kind = src.m_kind;
+ m_nonzero_mask = src.m_nonzero_mask;
return *this;
}
@@ -393,6 +394,7 @@ irange::irange_set (tree min, tree max)
m_num_ranges = 1;
m_kind = VR_RANGE;
normalize_kind ();
+ m_nonzero_mask = NULL;
if (flag_checking)
verify_range ();
@@ -466,6 +468,7 @@ irange::irange_set_anti_range (tree min, tree max)
m_kind = VR_RANGE;
normalize_kind ();
+ m_nonzero_mask = NULL;
if (flag_checking)
verify_range ();
@@ -524,6 +527,7 @@ irange::set (tree min, tree max, value_range_kind kind)
m_base[0] = min;
m_base[1] = max;
m_num_ranges = 1;
+ m_nonzero_mask = NULL;
return;
}
@@ -574,6 +578,7 @@ irange::set (tree min, tree max, value_range_kind kind)
m_base[1] = max;
m_num_ranges = 1;
normalize_kind ();
+ m_nonzero_mask = NULL;
if (flag_checking)
verify_range ();
}
@@ -587,8 +592,11 @@ irange::verify_range ()
if (m_kind == VR_UNDEFINED)
{
gcc_checking_assert (m_num_ranges == 0);
+ gcc_checking_assert (!m_nonzero_mask);
return;
}
+ if (m_nonzero_mask)
+ gcc_checking_assert (wi::to_wide (m_nonzero_mask) != -1);
if (m_kind == VR_VARYING)
{
gcc_checking_assert (m_num_ranges == 1);
@@ -680,11 +688,15 @@ irange::legacy_equal_p (const irange &other) const
if (m_kind == VR_UNDEFINED)
return true;
if (m_kind == VR_VARYING)
- return range_compatible_p (type (), other.type ());
+ {
+ return (range_compatible_p (type (), other.type ())
+ && vrp_operand_equal_p (m_nonzero_mask, other.m_nonzero_mask));
+ }
return (vrp_operand_equal_p (tree_lower_bound (0),
other.tree_lower_bound (0))
&& vrp_operand_equal_p (tree_upper_bound (0),
- other.tree_upper_bound (0)));
+ other.tree_upper_bound (0))
+ && vrp_operand_equal_p (m_nonzero_mask, other.m_nonzero_mask));
}
bool
@@ -716,7 +728,7 @@ irange::operator== (const irange &other) const
|| !operand_equal_p (ub, ub_other, 0))
return false;
}
- return true;
+ return vrp_operand_equal_p (m_nonzero_mask, other.m_nonzero_mask);
}
/* Return TRUE if this is a symbolic range. */
@@ -858,6 +870,14 @@ irange::contains_p (tree cst) const
}
gcc_checking_assert (TREE_CODE (cst) == INTEGER_CST);
+
+ if (m_nonzero_mask)
+ {
+ wide_int cstw = wi::to_wide (cst);
+ if (cstw != 0 && wi::bit_and (wi::to_wide (m_nonzero_mask), cstw) == 0)
+ return false;
+ }
+
signop sign = TYPE_SIGN (TREE_TYPE (cst));
wide_int v = wi::to_wide (cst);
for (unsigned r = 0; r < m_num_ranges; ++r)
@@ -1809,22 +1829,40 @@ irange::irange_union (const irange &r)
{
gcc_checking_assert (!legacy_mode_p () && !r.legacy_mode_p ());
- if (r.undefined_p () || varying_p ())
+ if (r.undefined_p ())
return false;
- if (undefined_p () || r.varying_p ())
+ if (undefined_p ())
{
operator= (r);
return true;
}
+ // Save the nonzero mask in case the set operations below clobber it.
+ bool ret_nz = union_nonzero_bits (r);
+ tree saved_nz = m_nonzero_mask;
+
+ if (varying_p ())
+ return ret_nz;
+
+ if (r.varying_p ())
+ {
+ set_varying (r.type ());
+ set_nonzero_bits (saved_nz);
+ return true;
+ }
+
// Special case one range union one range.
if (m_num_ranges == 1 && r.m_num_ranges == 1)
- return irange_single_pair_union (r);
+ {
+ bool ret = irange_single_pair_union (r);
+ set_nonzero_bits (saved_nz);
+ return ret || ret_nz;
+ }
// If this ranges fully contains R, then we need do nothing.
if (irange_contains_p (r))
- return false;
+ return ret_nz;
// Do not worry about merging and such by reserving twice as many
// pairs as needed, and then simply sort the 2 ranges into this
@@ -1913,6 +1951,7 @@ irange::irange_union (const irange &r)
m_kind = VR_RANGE;
normalize_kind ();
+ set_nonzero_bits (saved_nz);
if (flag_checking)
verify_range ();
@@ -1974,25 +2013,38 @@ irange::irange_intersect (const irange &r)
gcc_checking_assert (undefined_p () || r.undefined_p ()
|| range_compatible_p (type (), r.type ()));
- if (undefined_p () || r.varying_p ())
+ if (undefined_p ())
return false;
if (r.undefined_p ())
{
set_undefined ();
return true;
}
+
+ // Save the nonzero mask in case the set operations below clobber it.
+ bool ret_nz = intersect_nonzero_bits (r);
+ tree saved_nz = m_nonzero_mask;
+
+ if (r.varying_p ())
+ return ret_nz;
+
if (varying_p ())
{
operator= (r);
+ set_nonzero_bits (saved_nz);
return true;
}
if (r.num_pairs () == 1)
- return intersect (r.lower_bound (), r.upper_bound ());
+ {
+ bool res = intersect (r.lower_bound (), r.upper_bound ());
+ set_nonzero_bits (saved_nz);
+ return res || saved_nz;
+ }
// If R fully contains this, then intersection will change nothing.
if (r.irange_contains_p (*this))
- return false;
+ return ret_nz;
signop sign = TYPE_SIGN (TREE_TYPE(m_base[0]));
unsigned bld_pair = 0;
@@ -2064,6 +2116,8 @@ irange::irange_intersect (const irange &r)
m_kind = VR_RANGE;
normalize_kind ();
+ if (!undefined_p ())
+ set_nonzero_bits (saved_nz);
if (flag_checking)
verify_range ();
@@ -2074,6 +2128,8 @@ irange::irange_intersect (const irange &r)
// Multirange intersect for a specified wide_int [lb, ub] range.
// Return TRUE if intersect changed anything.
+//
+// NOTE: It is the caller's responsibility to intersect the nonzero masks.
bool
irange::intersect (const wide_int& lb, const wide_int& ub)
@@ -2277,6 +2333,90 @@ irange::invert ()
verify_range ();
}
+void
+irange::set_nonzero_bits (const wide_int_ref &bits)
+{
+ gcc_checking_assert (!undefined_p ());
+
+ if (bits == -1)
+ {
+ m_nonzero_mask = NULL;
+ return;
+ }
+ m_nonzero_mask = wide_int_to_tree (type (), bits);
+}
+
+wide_int
+irange::get_nonzero_bits () const
+{
+ gcc_checking_assert (!undefined_p ());
+ // Nonzero bits are unsupported in legacy mode. The mask may be set
+ // as a consequence of propagation or reading global ranges, but no
+ // one from legacy land should be querying this.
+ gcc_checking_assert (!legacy_mode_p ());
+
+ // Calculate the nonzero bits inherent in the range.
+ wide_int min = lower_bound ();
+ wide_int max = upper_bound ();
+ wide_int xorv = min ^ max;
+ if (xorv != 0)
+ {
+ unsigned prec = TYPE_PRECISION (type ());
+ xorv = wi::mask (prec - wi::clz (xorv), false, prec);
+ }
+ wide_int mask = min | xorv;
+
+ // Return the nonzero bits augmented by the range.
+ if (m_nonzero_mask)
+ return mask & wi::to_wide (m_nonzero_mask);
+
+ return mask;
+}
+
+// Intersect the nonzero bits in R into THIS.
+
+bool
+irange::intersect_nonzero_bits (const irange &r)
+{
+ gcc_checking_assert (!undefined_p () && !r.undefined_p ());
+
+ if (!r.m_nonzero_mask)
+ return false;
+ if (!m_nonzero_mask)
+ {
+ m_nonzero_mask = r.m_nonzero_mask;
+ return true;
+ }
+ wide_int i = wi::bit_and (wi::to_wide (m_nonzero_mask),
+ wi::to_wide (r.m_nonzero_mask));
+ set_nonzero_bits (i);
+ return true;
+}
+
+// Union the nonzero bits in R into THIS.
+
+bool
+irange::union_nonzero_bits (const irange &r)
+{
+ gcc_checking_assert (!undefined_p () && !r.undefined_p ());
+
+ if (!m_nonzero_mask)
+ return false;
+ if (!r.m_nonzero_mask)
+ {
+ if (m_nonzero_mask)
+ {
+ m_nonzero_mask = NULL;
+ return true;
+ }
+ return false;
+ }
+ wide_int i = wi::bit_or (wi::to_wide (m_nonzero_mask),
+ wi::to_wide (r.m_nonzero_mask));
+ set_nonzero_bits (i);
+ return true;
+}
+
static void
dump_bound_with_infinite_markers (FILE *file, tree bound)
{
@@ -2312,6 +2452,7 @@ irange::dump (FILE *file) const
if (varying_p ())
{
fprintf (file, "VARYING");
+ dump_bitmasks (file);
return;
}
if (legacy_mode_p ())
@@ -2321,6 +2462,7 @@ irange::dump (FILE *file) const
fprintf (file, ", ");
dump_bound_with_infinite_markers (file, max ());
fprintf (file, "]");
+ dump_bitmasks (file);
return;
}
for (unsigned i = 0; i < m_num_ranges; ++i)
@@ -2333,6 +2475,21 @@ irange::dump (FILE *file) const
dump_bound_with_infinite_markers (file, ub);
fprintf (file, "]");
}
+ dump_bitmasks (file);
+}
+
+void
+irange::dump_bitmasks (FILE *file) const
+{
+ if (m_nonzero_mask && !legacy_mode_p ())
+ {
+ wide_int nz = get_nonzero_bits ();
+ if (nz != -1)
+ {
+ fprintf (file, " NONZERO ");
+ print_hex (nz, file);
+ }
+ }
}
void
diff --git a/gcc/value-range.h b/gcc/value-range.h
index fd6703138ac..2e48d92d189 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -109,6 +109,7 @@ protected:
class GTY((user)) irange : public vrange
{
friend class vrange_allocator;
+ friend class irange_storage_slot; // For legacy_mode_p checks.
public:
// In-place setters.
virtual void set (tree, tree, value_range_kind = VR_RANGE) override;
@@ -149,6 +150,10 @@ public:
virtual bool fits_p (const vrange &r) const override;
virtual void dump (FILE * = stderr) const override;
+ // Nonzero masks.
+ wide_int get_nonzero_bits () const;
+ void set_nonzero_bits (const wide_int_ref &bits);
+
// Deprecated legacy public methods.
tree min () const; // DEPRECATED
tree max () const; // DEPRECATED
@@ -196,10 +201,15 @@ private:
void irange_set_1bit_anti_range (tree, tree);
bool varying_compatible_p () const;
+ void set_nonzero_bits (tree bits) { m_nonzero_mask = bits; }
+ bool intersect_nonzero_bits (const irange &r);
+ bool union_nonzero_bits (const irange &r);
+ void dump_bitmasks (FILE *) const;
bool intersect (const wide_int& lb, const wide_int& ub);
unsigned char m_num_ranges;
unsigned char m_max_ranges;
+ tree m_nonzero_mask;
tree *m_base;
};
@@ -608,6 +618,8 @@ gt_ggc_mx (irange *x)
gt_ggc_mx (x->m_base[i * 2]);
gt_ggc_mx (x->m_base[i * 2 + 1]);
}
+ if (x->m_nonzero_mask)
+ gt_ggc_mx (x->m_nonzero_mask);
}
inline void
@@ -618,6 +630,8 @@ gt_pch_nx (irange *x)
gt_pch_nx (x->m_base[i * 2]);
gt_pch_nx (x->m_base[i * 2 + 1]);
}
+ if (x->m_nonzero_mask)
+ gt_pch_nx (x->m_nonzero_mask);
}
inline void
@@ -628,6 +642,8 @@ gt_pch_nx (irange *x, gt_pointer_operator op, void *cookie)
op (&x->m_base[i * 2], NULL, cookie);
op (&x->m_base[i * 2 + 1], NULL, cookie);
}
+ if (x->m_nonzero_mask)
+ op (&x->m_nonzero_mask, NULL, cookie);
}
template<unsigned N>
@@ -722,6 +738,7 @@ irange::set_undefined ()
{
m_kind = VR_UNDEFINED;
m_num_ranges = 0;
+ m_nonzero_mask = NULL;
}
inline void
@@ -729,6 +746,7 @@ irange::set_varying (tree type)
{
m_kind = VR_VARYING;
m_num_ranges = 1;
+ m_nonzero_mask = NULL;
if (INTEGRAL_TYPE_P (type))
{
@@ -843,7 +861,7 @@ inline void
irange::normalize_kind ()
{
if (m_num_ranges == 0)
- m_kind = VR_UNDEFINED;
+ set_undefined ();
else if (varying_compatible_p ())
{
if (m_kind == VR_RANGE)
--
2.36.1
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