Re: [PATCH 5/8] target/ppc: Move multiply fixed-point insns (64-bit operands) to decodetree.

[Richard Henderson]

On 4/19/24 02:25, Chinmay Rath wrote:
> Hi Richard,
>
> On 4/17/24 00:06, Richard Henderson wrote:
> > On 4/15/24 23:39, Chinmay Rath wrote:
> > > +static bool trans_MADDHDU(DisasContext *ctx, arg_MADDHDU *a)
> > ...
> > > +    tcg_gen_movi_i64(t1, 0);
> >
> > Drop the movi.
> >
> > > +    tcg_gen_add2_i64(t1, cpu_gpr[a->vrt], lo, hi, cpu_gpr[a->rc], t1);
> >
> > Use tcg_constant_i64(0).
> Looks like tcg_gen_add2_i64 internally modifies the passed arguments, hence constant is 
> not expected.
> However, I tried using tcg_constant_i64(0) as suggested but this leads to an 
> assert failure :
> qemu-system-ppc64: ../tcg/tcg.c:5071: tcg_reg_alloc_op: Assertion `!temp_readonly(ts)' 
> failed.

You misunderstood my suggestion.

  TCGv_i64 t1 = tcg_temp_new_i64();
  tcg_gen_add2_i64(t1, cpu_gpr[vrt], lo, hi, cpu_gpr[a->rc], 
tcg_constantant_i64(0));


r~