https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86444
Bug ID: 86444 Summary: [X86] Implementation of SSE comi/ucomi intrinsics does not match recent versions of icc, clang, or MSVC Product: gcc Version: 9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: craig.topper at gmail dot com Target Milestone: --- It looks like gcc does not match the behavior of the most recent versions of icc, clang, and MSVC with respect to the behavior or NaNs in the COMI intrinsics. The other compilers are all returning 0 when the compare result is unordered. As can be seen here: https://godbolt.org/g/xxEKqg Clang changed to this behavior in version 3.9. According to this comment from https://bugs.llvm.org/show_bug.cgi?id=28510#c10, the original icc behavior was the same as gcc’s current behavior, but it was changed at least 10 years ago.