I don't believe we have support for defining sub-ranges of available registers for individual instructions. You could of course limit the whole program (or function) to a subset of registers by limiting the available allocatable registers. Another hack would be to define a fake live-range for the disallowed registers that covers the instruction in question, although this would also prevent the use of those registers by any other live ranges that intersect with that instruction.
Out of interest, is there any particular reason you would like to artificially limit register allocation for particular instructions? Cheers, Ross On Wed, 13 Nov 2019 at 21:50, <[email protected]> wrote: > I'm interested in the ability to restrict V8 from generating particular > instructions use of input/output registers to an [artificial] subset of > available allocatable registers, and I was curious if the constraint system > has this ability? > > My desire is different from the DefineFixed/UseFixed constraints, which > select an exact register code to be used for that operand. In my use-case, > I'd still like the register allocator to have freedom in choosing the exact > register mapping from a limited subset of registers (they can be forced to > be contiguous from a simplicity perspective). > > After a cursory review, none of the OperandGenerator's seem to match my > need at the surface - but I wanted to get some expert-level feedback in > case I missed something. > > Any feedback, insight, or intuition would be greatly appreciated. > > -- > -- > v8-dev mailing list > [email protected] > http://groups.google.com/group/v8-dev > --- > You received this message because you are subscribed to the Google Groups > "v8-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/v8-dev/f5a109ba-b759-4b2c-af3b-40b42adc20bd%40googlegroups.com > <https://groups.google.com/d/msgid/v8-dev/f5a109ba-b759-4b2c-af3b-40b42adc20bd%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- -- v8-dev mailing list [email protected] http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/v8-dev/CAP-rjT7RjvLmgxsN6tG%3DHBpLr%2BagKhb4KG4qUqoS1R1fzd-X%3Dw%40mail.gmail.com.
