https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108540
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:09176201ec6a21c25b1edb07f19f83be22a123f9 commit r13-5397-g09176201ec6a21c25b1edb07f19f83be22a123f9 Author: Jakub Jelinek <ja...@redhat.com> Date: Thu Jan 26 17:21:22 2023 +0100 frange: Fix up foperator_{,not_}equal::fold_range for signed zeros [PR108540] The following testcases are miscompiled, because threader sees some SSA_NAME would have -0.0 value and when computing range of SSA_NAME == 0.0 foperator_equal::fold_range sees one operand has [-0.0, -0.0] singleton range, the other [0.0, 0.0], they aren't equal (frange operator== uses real_identical etc. rather than real comparisons) and so it thinks they compare unequal. With signed zeros -0.0 == 0.0 is true though, so we need to special case the both ranges singleton code. Similarly, if we see op1 range being say [-42.0, -0.0] and op2 range [0.0, 42.0], we'd check that the intersection of the two ranges is empty (that is correct) and fold the result of == between such operands to [0, 0] which is wrong, because -0.0 == 0.0, it needs to be [0, 1]. Similarly for foperator_not_equal::fold_range. 2023-01-26 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/108540 * range-op-float.cc (foperator_equal::fold_range): If both op1 and op2 are singletons, use range_true even if op1 != op2 when one range is [-0.0, -0.0] and another [0.0, 0.0]. Similarly, even if intersection of the ranges is empty and one has zero low bound and another zero high bound, use range_true_and_false rather than range_false. (foperator_not_equal::fold_range): If both op1 and op2 are singletons, use range_false even if op1 != op2 when one range is [-0.0, -0.0] and another [0.0, 0.0]. Similarly, even if intersection of the ranges is empty and one has zero low bound and another zero high bound, use range_true_and_false rather than range_true. * gcc.c-torture/execute/ieee/pr108540-1.c: New test. * gcc.c-torture/execute/ieee/pr108540-2.c: New test.
