• Pierre Langlois's avatar
    Reland "[arm] Restrict grouping pushes before a TailCall to registers only" · 79bcb454
    Pierre Langlois authored
    This is a reland of a72b2f88
    Original change's description:
    > [arm] Restrict grouping pushes before a TailCall to registers only
    >
    > We optimize parallel moves performed before a TailCall by grouping adjacent
    > pushes. This way, we may use a single instruction to push multiple registers at
    > once. However, we also have support for pushing immediates and stack slots for
    > which the benefit is questionnable therefore this patch removes support for
    > them.
    >
    > Concerning immediate pushes, it looks like a mistake since we do not have
    > support for this case in `AssembleMove` so this patch removes it. Furthermore,
    > if we add a test for this case, we see that a `push ip` instruction is
    > generated, effectively pushing whatever was in `ip` at the time instead of
    > pushing a constant.
    >
    > Concerning stack slot pushes, we generate a more or less equivalent sequence of
    > instructions.
    >
    > Finally, grouping floating point pushes is not used anywhere so this patch
    > removes support for this also.
    >
    > Bug: v8:6553
    > Change-Id: I9b820d33361fc442dd813f66e1f96cda41009110
    > Reviewed-on: https://chromium-review.googlesource.com/567191
    > Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
    > Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
    > Cr-Commit-Position: refs/heads/master@{#46718}
    
    Bug: v8:6553
    Change-Id: Ib9a55dae7cc5db6185d163c56088ff23426d04bb
    Reviewed-on: https://chromium-review.googlesource.com/576087Reviewed-by: 's avatarBenedikt Meurer <bmeurer@chromium.org>
    Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
    Cr-Commit-Position: refs/heads/master@{#46754}
    79bcb454
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