From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2136) id 9FF3C3858C5E; Wed, 9 Nov 2022 07:03:53 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9FF3C3858C5E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1667977433; bh=EinMY0nPDgCKTBiSTjyTvtx618oOM0pLOBlDUQl+avI=; h=From:To:Subject:Date:From; b=agUrWMdKBfuyHFDknSQM7XceRDf8Vkr8REbioK6JdKxCgnb7wtpDOw5w9XmwmunHO jg5lF6GZQJBKhnLRzWNgqcB/qZw2D4cIFWtN7WjO+T2UGAwhnkE/YCGHh+5Xh54NyU CLh5LWP/slgEYtq1WDc+FoFos3Etdnas0sYAr93A= MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Aldy Hernandez To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-3823] [range-op-float] Set NAN possibility for INF + (-INF) and vice versa. X-Act-Checkin: gcc X-Git-Author: Aldy Hernandez X-Git-Refname: refs/heads/master X-Git-Oldrev: b305793b985f4d3e0032b04d446b8baabcb3e8b7 X-Git-Newrev: 68b0615be2aaff3a8ce91ba7cd0f69ebbd93702c Message-Id: <20221109070353.9FF3C3858C5E@sourceware.org> Date: Wed, 9 Nov 2022 07:03:53 +0000 (GMT) List-Id: https://gcc.gnu.org/g:68b0615be2aaff3a8ce91ba7cd0f69ebbd93702c commit r13-3823-g68b0615be2aaff3a8ce91ba7cd0f69ebbd93702c Author: Aldy Hernandez Date: Tue Nov 8 23:42:04 2022 +0100 [range-op-float] Set NAN possibility for INF + (-INF) and vice versa. Some combinations of operations can yield a NAN even if no operands have the possiblity of a NAN. For example, [-INF] + [+INF] = NAN and vice versa. For [-INF,+INF] + [-INF,+INF], frange_arithmetic will not return a NAN, and since the operands have no possibility of a NAN, we will mistakenly assume the result cannot have a NAN. This fixes the oversight. gcc/ChangeLog: * range-op-float.cc (foperator_plus::fold_range): Set NAN for addition of different signed infinities. (range_op_float_tests): New test. Diff: --- gcc/range-op-float.cc | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc index 3bc6cc8849d..8282c912fc4 100644 --- a/gcc/range-op-float.cc +++ b/gcc/range-op-float.cc @@ -1863,7 +1863,21 @@ foperator_plus::fold_range (frange &r, tree type, r.set (type, lb, ub); - if (lb_nan || ub_nan) + // Some combinations can yield a NAN even if no operands have the + // possibility of a NAN. + bool maybe_nan; + // [-INF] + [+INF] = NAN + if (real_isinf (&op1.lower_bound (), true) + && real_isinf (&op2.upper_bound (), false)) + maybe_nan = true; + // [+INF] + [-INF] = NAN + else if (real_isinf (&op1.upper_bound (), false) + && real_isinf (&op2.lower_bound (), true)) + maybe_nan = true; + else + maybe_nan = false; + + if (lb_nan || ub_nan || maybe_nan) // Keep the default NAN (with a varying sign) set by the setter. ; else if (!op1.maybe_isnan () && !op2.maybe_isnan ()) @@ -1960,6 +1974,16 @@ range_op_float_tests () r1 = frange_float ("-1", "-0"); r1.update_nan (false); ASSERT_EQ (r, r1); + + // [-INF,+INF] + [-INF,+INF] could be a NAN. + range_op_handler plus (PLUS_EXPR, float_type_node); + r0.set_varying (float_type_node); + r1.set_varying (float_type_node); + r0.clear_nan (); + r1.clear_nan (); + plus.fold_range (r, float_type_node, r0, r1); + if (HONOR_NANS (float_type_node)) + ASSERT_TRUE (r.maybe_isnan ()); } } // namespace selftest