• Benedikt Meurer's avatar
    [turbofan] Widen the fast-path for JSCreateArray. · 1edb46cc
    Benedikt Meurer authored
    This improves the general Array constructor call performance (w/o
    usable AllocationSite feedback) in TurboFan by ~2x, i.e. for example
    invoking the Array constructor like this
    
      var a = Array.call(undefined, n);
    
    instead of
    
      var a = Array(n);
    
    such that the CallIC doesn't know that it's eventually calling the
    Array constructor.
    
    It also thus changes the single argument Array constructor to always
    return holey arrays. Previously the single argument case for the Array
    constructor was somehow trying to dynamically detect 0 and in that case
    returned a packed array instead of a holey one. That adds quite a lot
    of churn, and doesn't seem to be very useful, especially since this
    might lead to unnecessary feedback pollution later.
    
    R=mvstanton@chromium.org
    
    Bug: v8:2229, v8:5269, v8:6399
    Change-Id: I3d7cb9bd975ec0e491e3cdbcf1230185cfd1e3de
    Reviewed-on: https://chromium-review.googlesource.com/565721Reviewed-by: 's avatarMichael Stanton <mvstanton@chromium.org>
    Reviewed-by: 's avatarBenedikt Meurer <bmeurer@chromium.org>
    Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#46538}
    1edb46cc
code-stubs-arm.cc 98.6 KB