Re: [Valgrind-developers] typeOfPrimop fixes

[Paul F. <pj...@wa...>]

On 05/07/2025 21:02, Florian Krohm wrote:
> What are the operand types of Iop_DivU128[E], Iop_ModU128 and their 
> signed counterparts?
>
> In libvex_ir.h these IROps are described to operate on Ity_I128 
> operands and produce a like typed result. This contradicts the 
> specification in ir_defs.c
> function typeOfprimop which claims Ity_V128 for operands and result.
>
> Above IROps are used exclusively by ppc for the following opcodes:
> Iop_DivU128  --> vdivuq  Vector Divide Unsigned Quadword
> Iop_DivS128  --> vdivsq  Vector Divide Signed Quadword
> Iop_DivU128E --> vdiveuq Vector Divide Extended Unsigned Quadword
> Iop_DivS128E --> vdivesq Vector Divide Extended Signed Quadword
> Iop_ModU128  --> vmoduq  Vector Modulo Unsigned Quadword
> Iop_ModS128  --> vmodsq  Vector Modulo Signed Quadword
>
> Reading the ISA document, it is clear, that those opcodes perform an
> integer division / modulo operation. Technically, they work on vector
> registers, presumably because vector registers are the only resource
> wide enough to store a quadword. Perhaps that is where the confusion
> comes from.
> So Ity_I128 it is.
>
> Below patch regtested on ppc with no new failures.
>
> OK?
>
VEX isn't my strong point, but it sounds OK to me.

A+

Paul