From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1011) id F0FCB3853833; Tue, 22 Jun 2021 13:17:30 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F0FCB3853833 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Andrew Macleod To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-1723] Add relation effects between operands to MINUS_EXPR. X-Act-Checkin: gcc X-Git-Author: Andrew MacLeod X-Git-Refname: refs/heads/master X-Git-Oldrev: c526de3f432a037bdbdd44eb6fa43af4f3b22694 X-Git-Newrev: ae6b830f31a47aca7ca24c4fea245c29214eef3a Message-Id: <20210622131730.F0FCB3853833@sourceware.org> Date: Tue, 22 Jun 2021 13:17:30 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Jun 2021 13:17:31 -0000 https://gcc.gnu.org/g:ae6b830f31a47aca7ca24c4fea245c29214eef3a commit r12-1723-gae6b830f31a47aca7ca24c4fea245c29214eef3a Author: Andrew MacLeod Date: Thu Jun 17 13:38:03 2021 -0400 Add relation effects between operands to MINUS_EXPR. * range-op.cc (operator_minus::op1_op2_relation_effect): New. Diff: --- gcc/range-op.cc | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/gcc/range-op.cc b/gcc/range-op.cc index a7698f21b0d..ec4816d69fa 100644 --- a/gcc/range-op.cc +++ b/gcc/range-op.cc @@ -1279,6 +1279,11 @@ public: const wide_int &lh_ub, const wide_int &rh_lb, const wide_int &rh_ub) const; + virtual bool op1_op2_relation_effect (irange &lhs_range, + tree type, + const irange &op1_range, + const irange &op2_range, + relation_kind rel) const; } op_minus; void @@ -1293,6 +1298,45 @@ operator_minus::wi_fold (irange &r, tree type, value_range_with_overflow (r, type, new_lb, new_ub, ov_lb, ov_ub); } +// Check to see if the relation REL between OP1 and OP2 has any effect on the +// LHS of the epxression. If so, apply it to LHS_RANGE. + +bool +operator_minus::op1_op2_relation_effect (irange &lhs_range, tree type, + const irange &op1_range ATTRIBUTE_UNUSED, + const irange &op2_range ATTRIBUTE_UNUSED, + relation_kind rel) const +{ + if (rel == VREL_NONE) + return false; + + int_range<2> rel_range; + unsigned prec = TYPE_PRECISION (type); + signop sgn = TYPE_SIGN (type); + + switch (rel) + { + // op1 > op2, op1 - op2 can be restricted to [1, max] + case GT_EXPR: + rel_range = int_range<2> (type, wi::one (prec), + wi::max_value (prec, sgn)); + break; + // op1 >= op2, op1 - op2 can be restricted to [0, max] + case GE_EXPR: + rel_range = int_range<2> (type, wi::zero (prec), + wi::max_value (prec, sgn)); + break; + // op1 == op2, op1 - op2 can be restricted to [0, 0] + case EQ_EXPR: + rel_range = int_range<2> (type, wi::zero (prec), wi::zero (prec)); + break; + default: + return false; + } + lhs_range.intersect (rel_range); + return true; +} + bool operator_minus::op1_range (irange &r, tree type, const irange &lhs,