Re: [Qemu-devel] [PATCH v4 6/6] target/sparc: optimize various functions using extract op

[Philippe Mathieu-Daudé]

On 05/12/2017 09:08 PM, Richard Henderson wrote:
> On 05/12/2017 04:38 PM, Philippe Mathieu-Daudé wrote:
[...]
> >   static inline void gen_op_add_cc(TCGv dst, TCGv src1, TCGv src2)
> > @@ -638,8 +634,7 @@ static inline void gen_op_mulscc(TCGv dst, TCGv 
> > src1, TCGv src2)
> >       // env->y = (b2 << 31) | (env->y >> 1);
> >       tcg_gen_andi_tl(r_temp, cpu_cc_src, 0x1);
> >       tcg_gen_shli_tl(r_temp, r_temp, 31);
> > -    tcg_gen_shri_tl(t0, cpu_y, 1);
> > -    tcg_gen_andi_tl(t0, t0, 0x7fffffff);
> > +    tcg_gen_extract_tl(t0, cpu_y, 1, 31);
> >       tcg_gen_or_tl(t0, t0, r_temp);
> >       tcg_gen_andi_tl(cpu_y, t0, 0xffffffff);

So this 0xffffffff mask is incorrect and should be 0x7fffffff?

> But this should use
>
>    tcg_gen_extract_tl(cpu_y, cpu_y, 1, 31);
>    tcg_gen_deposit_tl(cpu_y, cpu_y, cpu_cc_src, 31, 1);
>
>
> r~