https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106967
--- Comment #14 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:d2278da1c3cb7bf8b3d96c86dbef2982bf4cc54a commit r13-2756-gd2278da1c3cb7bf8b3d96c86dbef2982bf4cc54a Author: Aldy Hernandez <al...@redhat.com> Date: Tue Sep 20 16:19:14 2022 +0200 [PR106967] frange: revamp relational operators for NANs. Since NANs can be inserted by other passes even for -ffinite-math-only, we can't depend on the flag to determine if a NAN is a possiblity. Instead, we must explicitly check for them. In the case of -ffinite-math-only, paths leading up to a NAN are undefined and can be considered unreachable. I have audited all the relational code and made sure we're handling the known NAN case before anything else, setting undefined when appropriate. In the process, I revamped all the relational code handling NANs to correctly notice paths that are unreachable. The basic structure for ordered relational operators (except != of course) is this: If either operand is a known NAN, return FALSE. The true side of a relop when one operand is a NAN is unreachable. On the false side of a relop when one operand is a NAN, we know nothing about the other operand. Regstrapped on x86-64 and ppc64le Linux. lapack testing on x86-64 with and without -ffinite-math-only. PR tree-optimization/106967 gcc/ChangeLog: * range-op-float.cc (foperator_equal::fold_range): Adjust for NAN. (foperator_equal::op1_range): Same. (foperator_not_equal::fold_range): Same. (foperator_not_equal::op1_range): Same. (foperator_lt::fold_range): Same. (foperator_lt::op1_range): Same. (foperator_lt::op2_range): Same. (foperator_le::fold_range): Same. (foperator_le::op1_range): Same. (foperator_le::op2_range): Same. (foperator_gt::fold_range): Same. (foperator_gt::op1_range): Same. (foperator_gt::op2_range): Same. (foperator_ge::fold_range): Same. (foperator_ge::op1_range): Same. (foperator_ge::op2_range): Same. (foperator_unordered::op1_range): Same. (foperator_ordered::fold_range): Same. (foperator_ordered::op1_range): Same. (build_le): Assert that we don't have a NAN. (build_lt): Same. (build_gt): Same. (build_ge): Same. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/pr106967.c: New test.
