Hi,
As discussed in previous reviews, adding overflow APIs to range-op
would be useful. Those APIs could help to check if overflow happens
when operating between two 'range's, like: plus, minus, and mult.
Previous discussions are here:
https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624067.html
https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624701.html
Bootstrap & regtest pass on ppc64{,le} and x86_64.
Is this patch ok for trunk?
BR,
Jeff (Jiufu Guo)
gcc/ChangeLog:
* range-op-mixed.h (operator_plus::overflow_free_p): New declare.
(operator_minus::overflow_free_p): New declare.
(operator_mult::overflow_free_p): New declare.
* range-op.cc (range_op_handler::overflow_free_p): New function.
(range_operator::overflow_free_p): New default function.
(operator_plus::overflow_free_p): New function.
(operator_minus::overflow_free_p): New function.
(operator_mult::overflow_free_p): New function.
* range-op.h (range_op_handler::overflow_free_p): New declare.
(range_operator::overflow_free_p): New declare.
* value-range.cc (irange::nonnegative_p): New function.
(irange::nonpositive_p): New function.
* value-range.h (irange::nonnegative_p): New declare.
(irange::nonpositive_p): New declare.
---
gcc/range-op-mixed.h | 11 ++++
gcc/range-op.cc | 124 +++++++++++++++++++++++++++++++++++++++++++
gcc/range-op.h | 5 ++
gcc/value-range.cc | 12 +++++
gcc/value-range.h | 2 +
5 files changed, 154 insertions(+)
diff --git a/gcc/range-op-mixed.h b/gcc/range-op-mixed.h
index 6944742ecbc..42157ed9061 100644
--- a/gcc/range-op-mixed.h
+++ b/gcc/range-op-mixed.h
@@ -383,6 +383,10 @@ public:
relation_kind rel) const final override;
void update_bitmask (irange &r, const irange &lh,
const irange &rh) const final override;
+
+ virtual bool overflow_free_p (const irange &lh, const irange &rh,
+ relation_trio = TRIO_VARYING) const;
+
private:
void wi_fold (irange &r, tree type, const wide_int &lh_lb,
const wide_int &lh_ub, const wide_int &rh_lb,
@@ -446,6 +450,10 @@ public:
relation_kind rel) const final override;
void update_bitmask (irange &r, const irange &lh,
const irange &rh) const final override;
+
+ virtual bool overflow_free_p (const irange &lh, const irange &rh,
+ relation_trio = TRIO_VARYING) const;
+
private:
void wi_fold (irange &r, tree type, const wide_int &lh_lb,
const wide_int &lh_ub, const wide_int &rh_lb,
@@ -525,6 +533,9 @@ public:
const REAL_VALUE_TYPE &lh_lb, const REAL_VALUE_TYPE &lh_ub,
const REAL_VALUE_TYPE &rh_lb, const REAL_VALUE_TYPE &rh_ub,
relation_kind kind) const final override;
+ virtual bool overflow_free_p (const irange &lh, const irange &rh,
+ relation_trio = TRIO_VARYING) const;
+
};
class operator_addr_expr : public range_operator
diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index cb584314f4c..632b044331b 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -366,6 +366,22 @@ range_op_handler::op1_op2_relation (const vrange &lhs)
const
}
}
+bool
+range_op_handler::overflow_free_p (const vrange &lh,
+ const vrange &rh,
+ relation_trio rel) const
+{
+ gcc_checking_assert (m_operator);
+ switch (dispatch_kind (lh, lh, rh))
+ {
+ case RO_III:
+ return m_operator->overflow_free_p(as_a <irange> (lh),
+ as_a <irange> (rh),
+ rel);
+ default:
+ return false;
+ }
+}
// Convert irange bitmasks into a VALUE MASK pair suitable for calling CCP.
@@ -688,6 +704,13 @@ range_operator::op1_op2_relation_effect (irange &lhs_range ATTRIBUTE_UNUSED,
return false;
}
+bool
+range_operator::overflow_free_p (const irange &, const irange &,
+ relation_trio) const
+{
+ return false;
+}
+
// Apply any known bitmask updates based on this operator.
void
@@ -4311,6 +4334,107 @@ range_op_table::initialize_integral_ops ()
}
+bool
+operator_plus::overflow_free_p (const irange &lh, const irange &rh,
+ relation_trio) const
+{
+ if (lh.undefined_p () || rh.undefined_p ())
+ return false;
+
+ tree type = lh.type ();
+ if (TYPE_OVERFLOW_UNDEFINED (type))
+ return true;
+
+ wi::overflow_type ovf;
+ signop sgn = TYPE_SIGN (type);
+ wide_int wmax0 = lh.upper_bound ();
+ wide_int wmax1 = rh.upper_bound ();
+ wi::add (wmax0, wmax1, sgn, &ovf);
+ if (ovf != wi::OVF_NONE)
+ return false;
+
+ if (TYPE_UNSIGNED (type))
+ return true;
+
+ wide_int wmin0 = lh.lower_bound ();
+ wide_int wmin1 = rh.lower_bound ();
+ wi::add (wmin0, wmin1, sgn, &ovf);
+ if (ovf != wi::OVF_NONE)
+ return false;
+
+ return true;
+}
+
+bool
+operator_minus::overflow_free_p (const irange &lh, const irange &rh,
+ relation_trio) const
+{
+ if (lh.undefined_p () || rh.undefined_p ())
+ return false;
+
+ tree type = lh.type ();
+ if (TYPE_OVERFLOW_UNDEFINED (type))
+ return true;
+
+ wi::overflow_type ovf;
+ signop sgn = TYPE_SIGN (type);
+ wide_int wmin0 = lh.lower_bound ();
+ wide_int wmax1 = rh.upper_bound ();
+ wi::sub (wmin0, wmax1, sgn, &ovf);
+ if (ovf != wi::OVF_NONE)
+ return false;
+
+ if (TYPE_UNSIGNED (type))
+ return true;
+
+ wide_int wmax0 = lh.upper_bound ();
+ wide_int wmin1 = rh.lower_bound ();
+ wi::sub (wmax0, wmin1, sgn, &ovf);
+ if (ovf != wi::OVF_NONE)
+ return false;
+
+ return true;
+}
+
+bool
+operator_mult::overflow_free_p (const irange &lh, const irange &rh,
+ relation_trio) const
+{
+ if (lh.undefined_p () || rh.undefined_p ())
+ return false;
+
+ tree type = lh.type ();
+ if (TYPE_OVERFLOW_UNDEFINED (type))
+ return true;
+
+ wi::overflow_type ovf;
+ signop sgn = TYPE_SIGN (type);
+ wide_int wmax0 = lh.upper_bound ();
+ wide_int wmax1 = rh.upper_bound ();
+ wi::mul (wmax0, wmax1, sgn, &ovf);
+ if (ovf != wi::OVF_NONE)
+ return false;
+
+ if (TYPE_UNSIGNED (type))
+ return true;
+
+ wide_int wmin0 = lh.lower_bound ();
+ wide_int wmin1 = rh.lower_bound ();
+ wi::mul (wmin0, wmin1, sgn, &ovf);
+ if (ovf != wi::OVF_NONE)
+ return false;
+
+ wi::mul (wmin0, wmax1, sgn, &ovf);
+ if (ovf != wi::OVF_NONE)
+ return false;
+
+ wi::mul (wmax0, wmin1, sgn, &ovf);
+ if (ovf != wi::OVF_NONE)
+ return false;
+
+ return true;
+}
+
#if CHECKING_P
#include "selftest.h"
diff --git a/gcc/range-op.h b/gcc/range-op.h
index af94c2756a7..db3b03f28a5 100644
--- a/gcc/range-op.h
+++ b/gcc/range-op.h
@@ -147,6 +147,9 @@ public:
virtual relation_kind op1_op2_relation (const irange &lhs) const;
virtual relation_kind op1_op2_relation (const frange &lhs) const;
+
+ virtual bool overflow_free_p (const irange &lh, const irange &rh,
+ relation_trio = TRIO_VARYING) const;
protected:
// Perform an integral operation between 2 sub-ranges and return it.
virtual void wi_fold (irange &r, tree type,
@@ -214,6 +217,8 @@ public:
const vrange &op2,
relation_kind = VREL_VARYING) const;
relation_kind op1_op2_relation (const vrange &lhs) const;
+ bool overflow_free_p (const vrange &lh, const vrange &rh,
+ relation_trio = TRIO_VARYING) const;
protected:
unsigned dispatch_kind (const vrange &lhs, const vrange &op1,
const vrange& op2) const;
diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index 011bdbdeae6..5ae4e044194 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -313,6 +313,18 @@ add_vrange (const vrange &v, inchash::hash &hstate,
} //namespace inchash
+bool
+irange::nonnegative_p () const
+{
+ return wi::ge_p (lower_bound (), 0, TYPE_SIGN (type ()));
+}
+
+bool
+irange::nonpositive_p () const
+{
+ return wi::le_p (upper_bound (), 0, TYPE_SIGN (type ()));
+}
+
bool
irange::supports_type_p (const_tree type) const
{
diff --git a/gcc/value-range.h b/gcc/value-range.h
index 0170188201b..a12dea514e4 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -280,6 +280,8 @@ public:
virtual bool singleton_p (tree *result = NULL) const override;
bool singleton_p (wide_int &) const;
bool contains_p (const wide_int &) const;
+ bool nonnegative_p () const;
+ bool nonpositive_p () const;
// In-place operators.
virtual bool union_ (const vrange &) override;
