Re: [PATCH V5 1/2] Add overflow API for plus minus mult on range

[guojiufu <guojiufu@linux.ibm.com>]

On 2023-08-03 21:18, Andrew MacLeod wrote:
> This is OK.
> 

Thanks a lot!  Committed via r14-3582.


BR,
Jeff (Jiufu Guo)

> 
> On 8/2/23 22:18, Jiufu Guo wrote:
>> Hi,
>> 
>> I would like to have a ping on this patch.
>> 
>> BR,
>> Jeff (Jiufu Guo)
>> 
>> 
>> Jiufu Guo <guojiufu@linux.ibm.com> writes:
>> 
>>> 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;