From e9b0dd2afe7a9e8a3033340dfa26ec606930eef5 Mon Sep 17 00:00:00 2001 From: Aldy Hernandez Date: Wed, 31 Aug 2022 14:41:04 +0200 Subject: Add signbit property to frange to better model signed zeros. As discussed here: https://gcc.gnu.org/pipermail/gcc-patches/2022-August/600656.html This adds an frange property to keep track of the sign bit. We keep it updated at all times, but we don't use it make any decisions when !HONOR_SIGNED_ZEROS. With this property we can now query the range for the appropriate sign with frange::get_signbit (). Possible values are yes, no, and unknown. gcc/ChangeLog: * range-op-float.cc (foperator_equal::op1_range): Do not copy sign bit. (foperator_not_equal::op1_range): Same. * value-query.cc (range_query::get_tree_range): Set sign bit. * value-range-pretty-print.cc (vrange_printer::visit): Dump sign bit. * value-range.cc (frange::set_signbit): New. (frange::set): Adjust for sign bit. (frange::normalize_kind): Same. (frange::union_): Remove useless comment. (frange::intersect): Same. (frange::contains_p): Adjust for sign bit. (frange::singleton_p): Same. (frange::verify_range): Same. (range_tests_signbit): New tests. (range_tests_floats): Call range_tests_signbit. * value-range.h (class frange_props): Add signbit (class frange): Same. --- gcc/value-query.cc | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) (limited to 'gcc/value-query.cc') diff --git a/gcc/value-query.cc b/gcc/value-query.cc index 4637fb4..201f679 100644 --- a/gcc/value-query.cc +++ b/gcc/value-query.cc @@ -217,14 +217,25 @@ range_query::get_tree_range (vrange &r, tree expr, gimple *stmt) return true; case REAL_CST: - if (TREE_OVERFLOW_P (expr)) - expr = drop_tree_overflow (expr); - r.set (expr, expr); - if (real_isnan (TREE_REAL_CST_PTR (expr))) - as_a (r).set_nan (fp_prop::YES); - else - as_a (r).set_nan (fp_prop::NO); - return true; + { + if (TREE_OVERFLOW_P (expr)) + expr = drop_tree_overflow (expr); + + frange &f = as_a (r); + f.set (expr, expr); + + // Singletons from the tree world have known properties. + REAL_VALUE_TYPE *rv = TREE_REAL_CST_PTR (expr); + if (real_isnan (rv)) + f.set_nan (fp_prop::YES); + else + f.set_nan (fp_prop::NO); + if (real_isneg (rv)) + f.set_signbit (fp_prop::YES); + else + f.set_signbit (fp_prop::NO); + return true; + } case SSA_NAME: gimple_range_global (r, expr); -- cgit v1.1