On 5/2/19 2:42 AM, Alex Bennée wrote:
>> +static void tcg_reg_alloc_dup(TCGContext *s, const TCGOp *op)
>> +{
>> + const TCGLifeData arg_life = op->life;
>> + TCGRegSet dup_out_regs, dup_in_regs;
>> + TCGTemp *its, *ots;
>> + TCGType itype, vtype;
>> + unsigned vece;
>> + bool ok;
>> +
>> + ots = arg_temp(op->args[0]);
>> + its = arg_temp(op->args[1]);
>> +
>> + /* There should be no fixed vector registers. */
>> + tcg_debug_assert(!ots->fixed_reg);
>
> This threw me slightly. I guess you only really duplicate vectors so I'm
> wondering if this should be called tcg_vec_reg_alloc_dup? Or maybe just
> a bit of verbiage in a block comment above the helper?
Perhaps just a bit more verbiage.
The convention so far is "tcg_reg_alloc_<opcode>", where so far mov, movi, and
call have specialized allocators. Everything else happens in tcg_reg_alloc_op.
So tcg_reg_alloc_dup is correct for handling dup.
>> + case TEMP_VAL_MEM:
>> + /* TODO: dup from memory */
>> + tcg_out_ld(s, itype, ots->reg, its->mem_base->reg,
>> its->mem_offset);
>
> Should we be aborting here? That said it looks like you are loading
> something directly from the register memory address here...
No, we should not abort. We load the scalar value into a register that we have
allocated that matches the input constraint for dup. We then fall through...
>
>> + break;
>> +
>> + default:
>> + g_assert_not_reached();
>> + }
>> +
>> + /* We now have a vector input register, so dup must succeed. */
>> + ok = tcg_out_dup_vec(s, vtype, vece, ots->reg, ots->reg);
>> + tcg_debug_assert(ok);
... to here, where we duplicate the scalar across the vector.
Success.
The TODO comment is about duplicating directly from the memory slot, with a new
dupm primitive, which appears in the next patch.
r~
