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| author | Aldy Hernandez <aldyh@redhat.com> | 2022-08-31 14:41:04 +0200 |
|---|---|---|
| committer | Aldy Hernandez <aldyh@redhat.com> | 2022-09-01 13:19:07 +0200 |
| commit | e9b0dd2afe7a9e8a3033340dfa26ec606930eef5 (patch) | |
| tree | 5ba1ceb1e6770c9f6e9de27184b2cfe91741b5e1 /gcc/range-op-float.cc | |
| parent | 0e1b1222af5e5346df9431df817f2e7dca01bee6 (diff) | |
| download | gcc-e9b0dd2afe7a9e8a3033340dfa26ec606930eef5.zip gcc-e9b0dd2afe7a9e8a3033340dfa26ec606930eef5.tar.gz gcc-e9b0dd2afe7a9e8a3033340dfa26ec606930eef5.tar.bz2 | |
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.
Diffstat (limited to 'gcc/range-op-float.cc')
| -rw-r--r-- | gcc/range-op-float.cc | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc index c30f2af..2f1af40 100644 --- a/gcc/range-op-float.cc +++ b/gcc/range-op-float.cc @@ -361,6 +361,9 @@ foperator_equal::op1_range (frange &r, tree type, case BRS_TRUE: // If it's true, the result is the same as OP2. r = op2; + // Make sure we don't copy the sign bit if we may have a zero. + if (HONOR_SIGNED_ZEROS (type) && r.contains_p (build_zero_cst (type))) + r.set_signbit (fp_prop::VARYING); // The TRUE side of op1 == op2 implies op1 is !NAN. r.set_nan (fp_prop::NO); break; @@ -462,6 +465,9 @@ foperator_not_equal::op1_range (frange &r, tree type, case BRS_FALSE: // If it's false, the result is the same as OP2. r = op2; + // Make sure we don't copy the sign bit if we may have a zero. + if (HONOR_SIGNED_ZEROS (type) && r.contains_p (build_zero_cst (type))) + r.set_signbit (fp_prop::VARYING); // The FALSE side of op1 != op2 implies op1 is !NAN. r.set_nan (fp_prop::NO); break; |