[PATCH] D54719: [Intrinsic] Signed Fixed Point Multiplication Intrinsic

[Leonard Chan via Phabricator via llvm-commits]

leonardchan added a comment.

In https://reviews.llvm.org/D54719#1305542, @craig.topper wrote:

> Do we have examples of real hardware that implements this sort of instruction?
>
> Right now this intrinsic looks like its just reimplementing what you would get if you just emitted this IR
>
>   %a = sext iX %x to i2X
>   %b = sext iX %y to i2X
>   %c = mul i2X %a, %b
>   %d = lshr i2X %c, PRECISION
>   %e = trunc i2X %d to iX
>
>
> So I'm not sure if there's a need for an intrinsic unless that pattern is difficult to match to an instruction.


I think @ebevhan and @bjope may have hardware with fixed point instructions


Repository:
  rL LLVM

https://reviews.llvm.org/D54719