https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93356
--- 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:e978955dd720d5cc0e5141a1e9bbbbb943a3cc41 commit r10-6361-ge978955dd720d5cc0e5141a1e9bbbbb943a3cc41 Author: David Malcolm <dmalc...@redhat.com> Date: Thu Jan 30 12:35:46 2020 -0500 analyzer: fix ICE in __builtin_isnan (PR 93356) PR analyzer/93356 reports an ICE handling __builtin_isnan due to a failing assertion: 674 gcc_assert (lhs_ec_id != rhs_ec_id); with op=UNORDERED_EXPR. when attempting to add an UNORDERED_EXPR constraint. This is an overzealous assertion, but underlying it are various forms of sloppiness regarding NaN within the analyzer: (a) the assumption in the constraint_manager that equivalence classes are reflexive (X == X), which isn't the case for NaN. (b) Hardcoding the "honor_nans" param to false when calling invert_tree_comparison throughout the analyzer. (c) Ignoring ORDERED_EXPR, UNORDERED_EXPR, and the UN-prefixed comparison codes. I wrote a patch for this which tracks the NaN-ness of floating-point values and uses this to address all of the above. However, to minimize changes in gcc 10 stage 4, here's a simpler patch which rejects attempts to query or add constraints on floating-point values, instead treating any floating-point comparison as "unknown", and silently dropping the constraints at edges. gcc/analyzer/ChangeLog: PR analyzer/93356 * region-model.cc (region_model::eval_condition): In both overloads, bail out immediately on floating-point types. (region_model::eval_condition_without_cm): Likewise. (region_model::add_constraint): Likewise. gcc/testsuite/ChangeLog: PR analyzer/93356 * gcc.dg/analyzer/conditionals-notrans.c (test_float_selfcmp): Add. * gcc.dg/analyzer/conditionals-trans.c: Mark floating point comparison test as failing. (test_float_selfcmp): Add. * gcc.dg/analyzer/data-model-1.c: Mark floating point comparison tests as failing. * gcc.dg/analyzer/torture/pr93356.c: New test. gcc/ChangeLog: PR analyzer/93356 * doc/analyzer.texi (Limitations): Note that constraints on floating-point values are currently ignored.
