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| author | Aldy Hernandez <aldyh@redhat.com> | 2022-11-08 23:42:04 +0100 |
|---|---|---|
| committer | Aldy Hernandez <aldyh@redhat.com> | 2022-11-09 07:56:35 +0100 |
| commit | 68b0615be2aaff3a8ce91ba7cd0f69ebbd93702c (patch) | |
| tree | 64cc83a874d962de4b3a4c937b0c224fd8b68e19 | |
| parent | b305793b985f4d3e0032b04d446b8baabcb3e8b7 (diff) | |
| download | gcc-68b0615be2aaff3a8ce91ba7cd0f69ebbd93702c.zip gcc-68b0615be2aaff3a8ce91ba7cd0f69ebbd93702c.tar.gz gcc-68b0615be2aaff3a8ce91ba7cd0f69ebbd93702c.tar.bz2 | |
[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.
| -rw-r--r-- | gcc/range-op-float.cc | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc index 3bc6cc8..8282c91 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 |