Re: [PATCH v2 01/50] accel/tcg: Add bitreverse and funnel-shift runtime helper functions

On 30/7/26 05:09, Anton Johansson via qemu development wrote:
> Adds necessary helper functions for mapping LLVM IR onto TCG.
> Specifically, helpers corresponding to the bitreverse and funnel-shift
> intrinsics in LLVM.
> 
> Note: these may be converted to more efficient implementations in the
> future, but for the time being it allows helper-to-tcg to support a
> wider subset of LLVM IR.
> 
> Signed-off-by: Anton Johansson <[email protected]>
> --
> TODO: `tcg_gen_*()` variants will be added in the next version, it
> slipped through (Richard).
> ---
>   accel/tcg/tcg-runtime.c | 28 ++++++++++++++++++++++++++++
>   accel/tcg/tcg-runtime.h |  6 ++++++
>   2 files changed, 34 insertions(+)


> +uint32_t HELPER(bitreverse8_i32)(uint32_t x)
> +{
> +  return revbit8((uint8_t) x);
> +}
> +
> +uint32_t HELPER(bitreverse16_i32)(uint32_t x)
> +{
> +  return revbit16((uint16_t) x);
> +}
> +
> +uint32_t HELPER(bitreverse32_i32)(uint32_t x)
> +{
> +  return revbit32(x);
> +}

Please split in 2 patches, adding bitreverse family in
one, and fshl_i64 in another.

For bitreverse:
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>

>   /* 64-bit helpers */
>   
> +uint64_t HELPER(fshl_i64)(uint64_t a, uint64_t b, uint64_t c)

Please use clearer hi/lo/sh/val/ret instead of a/b/c/d/shift:

   HELPER(fshl_i64)(uint64_t hi, uint64_t lo, uint64_t sh)

> +{
> +    Int128 d = int128_make128(b, a);
> +    Int128 shift = int128_lshift(d, c);
> +    return int128_gethi(shift);
> +}