[Bug analyzer/93451] ICE: qsort checking failed (error: qsort comparator non-negative on sorted output: 0)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93451

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Malcolm <dmalc...@gcc.gnu.org>:

https://gcc.gnu.org/g:8c08c983015e675f555d57a30e15d918abef2b93

commit r10-6271-g8c08c983015e675f555d57a30e15d918abef2b93
Author: David Malcolm <dmalc...@redhat.com>
Date:   Mon Jan 27 16:23:43 2020 -0500

    analyzer: fix ICE when canonicalizing NaN (PR 93451)

    PR analyzer/93451 reports an ICE when canonicalizing the constants
    in a region_model, with a failed qsort_chk when attempting to sort
    the constants within the region_model.

    The svalues in the model were:
      sv0: {poisoned: uninit}
      sv1: {type: ‘double’, ‘0.0’}
      sv2: {type: ‘double’, ‘1.0e+0’}
      sv3: {type: ‘double’, ‘ Nan’}

    The qsort_chk of the 3 constants fails due to tree_cmp using the
    LT_EXPR ordering of the REAL_CSTs, which doesn't work for NaN.

    This patch adjusts tree_cmp to impose an arbitrary ordering during
    canonicalization for UNORDERED_EXPR cases w/o relying on the LT_EXPR
    ordering, fixing the ICE.

    gcc/analyzer/ChangeLog:
        PR analyzer/93451
        * region-model.cc (tree_cmp): For the REAL_CST case, impose an
        arbitrary order on NaNs relative to other NaNs and to non-NaNs;
        const-correctness tweak.
        (ana::selftests::build_real_cst_from_string): New function.
        (ana::selftests::append_interesting_constants): New function.
        (ana::selftests::test_tree_cmp_on_constants): New test.
        (ana::selftests::test_canonicalization_4): New test.
        (ana::selftests::analyzer_region_model_cc_tests): Call the new
        tests.

    gcc/testsuite/ChangeLog:
        PR analyzer/93451
        * gcc.dg/analyzer/torture/pr93451.c: New test.