On Fri, Feb 15, 2019 at 6:47 PM Ted Mielczarek <t...@mielczarek.org> wrote: > > On Fri, Feb 15, 2019, at 4:00 AM, Henri Sivonen wrote: > > How committed are we to -fno-strict-aliasing? > > FWIW, some work was done to investigate re-enabling strict aliasing a while > ago but it proved untenable at the time: > https://bugzilla.mozilla.org/show_bug.cgi?id=414641
The bug was closed with "Realistically, this is WONTFIX. Life is too short to figure out why -O3 breaks -fstrict-aliasing." That conclusion makes sense to me. Is there any reason to believe that strict-aliasing in clang would yield the kind of performance benefits that would outweigh the trouble of writing strict-aliasing-conformant code and the performance penalties of additional memcpy() required for strict-aliasing-conformant code? Out of curiosity: Do we know if WebKit and Chromium compile with or without strict-aliasing? On Fri, Feb 15, 2019 at 4:43 PM David Major <dma...@mozilla.com> wrote: > If we can easily remove (or reduce) uses of this flag, I think > that would be pretty uncontroversial. What are the UB implications of using it for some parts of the code but not for others in the context of LTO? If we have specific places where we'd need strict-aliasing for performance, shouldn't we write those bits in Rust, which combines the perf benefits of -fstrict-aliasing with the understandability of -fno-strict-aliasing? -- Henri Sivonen hsivo...@mozilla.com _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
