https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106785
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Aldy Hernandez <al...@gcc.gnu.org>: https://gcc.gnu.org/g:bdfe0d1ce0aebdb68b77e2c04a0f45956c56b449 commit r13-2334-gbdfe0d1ce0aebdb68b77e2c04a0f45956c56b449 Author: Aldy Hernandez <al...@redhat.com> Date: Wed Aug 31 14:31:12 2022 +0200 Make frange selftests work on !HONOR_NANS systems. I'm just shuffling the FP self tests here, with no change to existing functionality. If we agree that explicit NANs in the source code with !HONOR_NANS should behave any differently, I'm happy to address whatever needs fixing, but for now I'd like to unblock the !HONOR_NANS build systems. I have added an adaptation of a test Jakub suggested we handle in the PR: void funk(int cond) { float x; if (cond) x = __builtin_nan (""); else x = 1.24; bar(x); } For !HONOR_NANS, the range for the PHI of x_1 is the union of 1.24 and NAN which is really 1.24 with a maybe NAN. This reflects the IL-- the presence of the actual NAN. However, VRP will propagate this because it sees the 1.24 and ignores the possibility of a NAN, per !HONOR_NANS. IMO, this is correct. OTOH, for HONOR_NANS the unknown NAN property keeps us from propagating the value. Is there a reason we don't warn for calls to __builtin_nan when !HONOR_NANS? That makes no sense to me. PR tree-optimization/106785 gcc/ChangeLog: * value-range.cc (range_tests_nan): Adjust tests for !HONOR_NANS. (range_tests_floats): Same. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/vrp-float-nan-1.c: New test.