Hi!
On Tue, Jul 07, 2020 at 04:39:58PM +0800, luoxhu wrote:
> > Lots of questions, sorry!
>
> Thanks for the nice suggestions of the initial patch contains many issues:),
Pretty much all of it should *work*, it just can be improved and
simplified quite a bit :-)
> For this case, %1:SF matches with "=wa"? And how to construct cases to
> match("=?r", "wa") and ("=!r", "r") combinations, please?
operands[0], not operands[1]?
Simple testcases will not put the output into a GPR, unless you force
the compiler to do that, because of the ? and !.
Often you can just do
asm("#" : "+r"(x));
to force "x" into a GPR at that point of the program. But there is
nothing stopping the compiler from copying it back to a VSR where it
thinks that is cheaper ;-)
So maybe this pattern should just have the GPR-to-VSR alternative? It
does not look like the GPR destination variants are useful?
> + rtx op0 = operands[0];
> + rtx op1 = operands[1];
> + rtx op2 = operands[2];
(Please just write out operands[N] everywhere).
> + if (GET_CODE (operands[2]) == SCRATCH)
> + op2 = gen_reg_rtx (DImode);
> +
> + rtx mask = GEN_INT (HOST_WIDE_INT_M1U << 32);
> + emit_insn (gen_anddi3 (op2, op1, mask));
Groovy :-)
So, it looks like you can remove the ? and ! alternatives, leaving just
the first alternative?
Segher
