On 7/1/25 09:00, Richard Henderson wrote:
> When we generalize {s}extract_i32, we'll lose the
> specific register constraints on ext8u and ext8s.
> It's just as easy to emit a couple of insns instead.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> tcg/i386/tcg-target.c.inc | 23 +++++++++++++++++++----
> 1 file changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
> index e51269f81d..047c5da81c 100644
> --- a/tcg/i386/tcg-target.c.inc
> +++ b/tcg/i386/tcg-target.c.inc
> @@ -1329,16 +1329,31 @@ static inline void tcg_out_rolw_8(TCGContext *s, int reg)
>
> static void tcg_out_ext8u(TCGContext *s, TCGReg dest, TCGReg src)
> {
> - /* movzbl */
> - tcg_debug_assert(src < 4 || TCG_TARGET_REG_BITS == 64);
> + if (TCG_TARGET_REG_BITS == 32 && src >= 4) {
> + tcg_out_mov(s, TCG_TYPE_I32, dest, src);
> + if (dest >= 4) {
> + tcg_out_modrm(s, OPC_ARITH_EvIz, ARITH_AND, dest);
> + tcg_out32(s, 0xff);
> + return;
> + }
> + src = dest;
> + }
> tcg_out_modrm(s, OPC_MOVZBL + P_REXB_RM, dest, src);
> }
>
> static void tcg_out_ext8s(TCGContext *s, TCGType type, TCGReg dest, TCGReg src)
> {
> int rexw = type == TCG_TYPE_I32 ? 0 : P_REXW;
> - /* movsbl */
> - tcg_debug_assert(src < 4 || TCG_TARGET_REG_BITS == 64);
> +
> + if (TCG_TARGET_REG_BITS == 32 && src >= 4) {
> + tcg_out_mov(s, TCG_TYPE_I32, dest, src);
> + if (dest >= 4) {
> + tcg_out_shifti(s, SHIFT_SHL, dest, 24);
> + tcg_out_shifti(s, SHIFT_SAR, dest, 24);
> + return;
> + }
> + src = dest;
> + }
> tcg_out_modrm(s, OPC_MOVSBL + P_REXB_RM + rexw, dest, src);
> }
>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>