On Tue, Feb 6, 2018 at 12:49 PM, Andy Lutomirski [off-list ref] wrote:

Can you use @cc to make an asm statement that outputs both the masked
array index and the "if" condition?  I can never remember the syntax,
but something like:

Yes. Although I'd actually suggest just using an "asm goto" if we
really want to optimize this. Give the "index_mask_nospec()" a third
argument that is the label to jump to for overflow.

Then you can just decide how to implement it best for any particular
architecture (and compiler limitation).

              Linus