[llvm-commits] [PATCH] Prevent the mixing of S and D registers for vsqrt/vdiv instructions on A15

[Tim Northover]

Hi all,

> The attached patch prevents the mixing of D and S registers for vsqrt/vdiv
> instructions when using neonfp on A15. This is necessary since single
> precision math instructions use D registers when using neonfp, and there
> are no equivalent instructions for vsqrt and vdiv.

I've taken a look at the patch, and while the extra duplicated
instruction to support this is rather a hack, I can't see any other
way to enforce the allocation constraints in that pattern.

This is  probably a necessary evil.

Tim.