Re: [PATCH 1/1] tcg/loongarch64: Fix tcg_out_mov() Aborted

[gaosong]

在 2023/11/20 下午11:59, Richard Henderson 写道:
> On 11/19/23 22:59, Song Gao wrote:
> > On LoongArch host,  we got an Aborted from tcg_out_mov().
> >
> > qemu-x86_64 configure with '--enable-debug'.
> >
> > > (gdb) b /home1/gaosong/code/qemu/tcg/loongarch64/tcg-target.c.inc:312
> > > Breakpoint 1 at 0x2576f0: file 
> > > /home1/gaosong/code/qemu/tcg/loongarch64/tcg-target.c.inc, line 312.
> > > (gdb) run hello
> > [...]
> > > Thread 1 "qemu-x86_64" hit Breakpoint 1, tcg_out_mov (s=0xaaaae91760 
> > > <tcg_init_ctx>, type=TCG_TYPE_V128, ret=TCG_REG_V2,
> > >      arg=TCG_REG_V0) at 
> > > /home1/gaosong/code/qemu/tcg/loongarch64/tcg-target.c.inc:312
> > > 312           g_assert_not_reached();
> > > (gdb) bt
> > > #0  tcg_out_mov (s=0xaaaae91760 <tcg_init_ctx>, type=TCG_TYPE_V128, 
> > > ret=TCG_REG_V2, arg=TCG_REG_V0)
> > >      at /home1/gaosong/code/qemu/tcg/loongarch64/tcg-target.c.inc:312
> > > #1  0x000000aaaad0fee0 in tcg_reg_alloc_mov (s=0xaaaae91760 
> > > <tcg_init_ctx>, op=0xaaaaf67c20) at ../tcg/tcg.c:4632
> > > #2  0x000000aaaad142f4 in tcg_gen_code (s=0xaaaae91760 
> > > <tcg_init_ctx>, tb=0xffe8030340 <code_gen_buffer+197328>,
> > >      pc_start=4346094) at ../tcg/tcg.c:6135
> > [...]
> > > (gdb) c
> > > Continuing.
> > > **
> > > ERROR:/home1/gaosong/code/qemu/tcg/loongarch64/tcg-target.c.inc:312:tcg_out_mov: 
> > > code should not be reached
> > > Bail out! 
> > > ERROR:/home1/gaosong/code/qemu/tcg/loongarch64/tcg-target.c.inc:312:tcg_out_mov: 
> > > code should not be reached
> > >
> > > Thread 1 "qemu-x86_64" received signal SIGABRT, Aborted.
> > > 0x000000fff7b1c390 in raise () from /lib64/libc.so.6
> > > (gdb) q
> >
> > Signed-off-by: Song Gao <gaosong@loongson.cn>
> > ---
> >   tcg/loongarch64/tcg-target.c.inc | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/tcg/loongarch64/tcg-target.c.inc 
> > b/tcg/loongarch64/tcg-target.c.inc
> > index a588fb3085..5f68040230 100644
> > --- a/tcg/loongarch64/tcg-target.c.inc
> > +++ b/tcg/loongarch64/tcg-target.c.inc
> > @@ -308,6 +308,9 @@ static bool tcg_out_mov(TCGContext *s, TCGType 
> > type, TCGReg ret, TCGReg arg)
> >            */
> >           tcg_out_opc_or(s, ret, arg, TCG_REG_ZERO);
> >           break;
> > +    case TCG_TYPE_V128:
> > +        tcg_out_opc_vaddi_du(s, ret, arg, 0);
> > +        break;
>
> Is add with immediate zero really the canonical alias for "vector move"?
>
> There is often some form that is recommended by the architecture, so 
> that it may be recognized for register renaming.  Usually it is some 
> form of logic instruction, not arithmetic.  I see that LLVM emits 
> "vori.b dst, src, 0" for this case.
> adfadf
you are right,
I see  the insn  'mov '  opcode is '00150000'.  it is 'or dst, src, zero'.

Thanks.
Song Gao
> Regardless, this patch works to fix the assert so,
>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>
>
> r~