Re: [PATCH v2 03/22] tcg/i386: Split out target constraints to tcg-target-con-str.h

[Richard Henderson]

On 1/19/21 4:38 AM, Peter Maydell wrote:
>> -    case 's':
>> -        /* qemu_st8_i32 data constraint */
>> -        ct->regs = 0xf;
>> -#ifdef CONFIG_SOFTMMU
>> -        tcg_regset_reset_reg(ct->regs, TCG_REG_L0);
>> -        tcg_regset_reset_reg(ct->regs, TCG_REG_L1);
>> -#endif
>> -        break;
> 
> But in the old code the 's' constraint is 0xf for both
> x86-64 and i386.

That's perhaps laziness, or simply the lack of names in the old code.  It
logically should be BYTEL, because that's where byte stores go from.

In the end it doesn't matter, because this constraint is *only* used by i386.
The opcode INDEX_op_qemu_st8_i32 is not used by x86_64 at all.  See
TCG_TARGET_HAS_qemu_st8_i32 in tcg-target.h.


r~