* [PATCH] tcg/loongarch64: Support every TCGCond for cmp_vec ops
@ 2025-12-06 18:24 WANG Xuerui
2025-12-08 15:40 ` Richard Henderson
0 siblings, 1 reply; 2+ messages in thread
From: WANG Xuerui @ 2025-12-06 18:24 UTC (permalink / raw)
To: qemu-devel
Cc: WANG Xuerui, Richard Henderson, Philippe Mathieu-Daudé, xtex
From: WANG Xuerui <git@xen0n.name>
Support for TCGCond's in loongarch64 cmp_vec codegen is not uniform: NE
is not supported at all and will trip over assertions, and legalization
(currently just operand-swapping) is not done for reg-imm comparisons.
Since the TCG middle-end will not legalize the comparison conditions for
us, we have to do it ourselves like other targets.
Because EQ/LT/LTU/LE/LEU are natively supported, we only have to keep
the current operand swapping treatment for GT/GTU/GE/GEU but ensure it
is done for both reg-reg and reg-imm cases, and use a bitwise NOT to
help legalize NE.
While at it, lift the cmp_vec handling to own function to make it easier
for readers.
Fixes: d8b6fa593d2d ("tcg/loongarch64: Lower cmp_vec to vseq/vsle/vslt")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3237
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
Reported-by: xtex <xtex@aosc.io>
Signed-off-by: WANG Xuerui <git@xen0n.name>
---
tcg/loongarch64/tcg-target.c.inc | 119 +++++++++++++++++++------------
1 file changed, 75 insertions(+), 44 deletions(-)
diff --git a/tcg/loongarch64/tcg-target.c.inc b/tcg/loongarch64/tcg-target.c.inc
index 10c69211ac5..1a243a57beb 100644
--- a/tcg/loongarch64/tcg-target.c.inc
+++ b/tcg/loongarch64/tcg-target.c.inc
@@ -2179,15 +2179,38 @@ static void tcg_out_addsub_vec(TCGContext *s, bool lasx, unsigned vece,
tcg_out32(s, encode_vdvjvk_insn(insn, a0, a1, a2));
}
-static void tcg_out_vec_op(TCGContext *s, TCGOpcode opc,
- unsigned vecl, unsigned vece,
- const TCGArg args[TCG_MAX_OP_ARGS],
- const int const_args[TCG_MAX_OP_ARGS])
+static void tcg_out_cmp_vec(TCGContext *s, bool lasx, unsigned vece,
+ TCGArg a0, TCGArg a1, TCGArg a2,
+ bool a2_is_const, TCGCond cond)
{
- TCGType type = vecl + TCG_TYPE_V64;
- bool lasx = type == TCG_TYPE_V256;
- TCGArg a0, a1, a2, a3;
LoongArchInsn insn;
+ bool need_invert = false;
+
+ switch (cond) {
+ case TCG_COND_EQ:
+ case TCG_COND_LE:
+ case TCG_COND_LEU:
+ case TCG_COND_LT:
+ case TCG_COND_LTU:
+ /* These are directly expressible. */
+ break;
+ case TCG_COND_NE:
+ need_invert = true;
+ cond = TCG_COND_EQ;
+ break;
+ case TCG_COND_GE:
+ case TCG_COND_GEU:
+ case TCG_COND_GT:
+ case TCG_COND_GTU:
+ {
+ TCGArg t;
+ t = a1, a1 = a2, a2 = t;
+ cond = tcg_swap_cond(cond);
+ break;
+ }
+ default:
+ g_assert_not_reached();
+ }
static const LoongArchInsn cmp_vec_insn[16][2][4] = {
[TCG_COND_EQ] = {
@@ -2233,6 +2256,49 @@ static void tcg_out_vec_op(TCGContext *s, TCGOpcode opc,
{ OPC_XVSLTI_BU, OPC_XVSLTI_HU, OPC_XVSLTI_WU, OPC_XVSLTI_DU },
}
};
+
+ if (a2_is_const) {
+ /*
+ * cmp_vec dest, src, value
+ * Try vseqi/vslei/vslti
+ */
+ int64_t value = sextract64(a2, 0, 8 << vece);
+
+ insn = cmp_vec_imm_insn[cond][lasx][vece];
+ switch (cond) {
+ case TCG_COND_EQ:
+ case TCG_COND_LE:
+ case TCG_COND_LT:
+ tcg_out32(s, encode_vdvjsk5_insn(insn, a0, a1, value));
+ break;
+ case TCG_COND_LEU:
+ case TCG_COND_LTU:
+ tcg_out32(s, encode_vdvjuk5_insn(insn, a0, a1, value));
+ break;
+ default:
+ g_assert_not_reached();
+ }
+ } else {
+ insn = cmp_vec_insn[cond][lasx][vece];
+ tcg_out32(s, encode_vdvjvk_insn(insn, a0, a1, a2));
+ }
+
+ if (need_invert) {
+ insn = lasx ? OPC_XVNOR_V : OPC_VNOR_V;
+ tcg_out32(s, encode_vdvjvk_insn(insn, a0, a0, a0));
+ }
+}
+
+static void tcg_out_vec_op(TCGContext *s, TCGOpcode opc,
+ unsigned vecl, unsigned vece,
+ const TCGArg args[TCG_MAX_OP_ARGS],
+ const int const_args[TCG_MAX_OP_ARGS])
+{
+ TCGType type = vecl + TCG_TYPE_V64;
+ bool lasx = type == TCG_TYPE_V256;
+ TCGArg a0, a1, a2, a3;
+ LoongArchInsn insn;
+
static const LoongArchInsn neg_vec_insn[2][4] = {
{ OPC_VNEG_B, OPC_VNEG_H, OPC_VNEG_W, OPC_VNEG_D },
{ OPC_XVNEG_B, OPC_XVNEG_H, OPC_XVNEG_W, OPC_XVNEG_D },
@@ -2347,43 +2413,8 @@ static void tcg_out_vec_op(TCGContext *s, TCGOpcode opc,
insn = lasx ? OPC_XVNOR_V : OPC_VNOR_V;
goto vdvjvk;
case INDEX_op_cmp_vec:
- {
- TCGCond cond = args[3];
-
- if (const_args[2]) {
- /*
- * cmp_vec dest, src, value
- * Try vseqi/vslei/vslti
- */
- int64_t value = sextract64(a2, 0, 8 << vece);
- switch (cond) {
- case TCG_COND_EQ:
- case TCG_COND_LE:
- case TCG_COND_LT:
- insn = cmp_vec_imm_insn[cond][lasx][vece];
- tcg_out32(s, encode_vdvjsk5_insn(insn, a0, a1, value));
- break;
- case TCG_COND_LEU:
- case TCG_COND_LTU:
- insn = cmp_vec_imm_insn[cond][lasx][vece];
- tcg_out32(s, encode_vdvjuk5_insn(insn, a0, a1, value));
- break;
- default:
- g_assert_not_reached();
- }
- break;
- }
-
- insn = cmp_vec_insn[cond][lasx][vece];
- if (insn == 0) {
- TCGArg t;
- t = a1, a1 = a2, a2 = t;
- cond = tcg_swap_cond(cond);
- insn = cmp_vec_insn[cond][lasx][vece];
- tcg_debug_assert(insn != 0);
- }
- }
- goto vdvjvk;
+ tcg_out_cmp_vec(s, lasx, vece, a0, a1, a2, const_args[2], a3);
+ break;
case INDEX_op_add_vec:
tcg_out_addsub_vec(s, lasx, vece, a0, a1, a2, const_args[2], true);
break;
--
2.52.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] tcg/loongarch64: Support every TCGCond for cmp_vec ops
2025-12-06 18:24 [PATCH] tcg/loongarch64: Support every TCGCond for cmp_vec ops WANG Xuerui
@ 2025-12-08 15:40 ` Richard Henderson
0 siblings, 0 replies; 2+ messages in thread
From: Richard Henderson @ 2025-12-08 15:40 UTC (permalink / raw)
To: WANG Xuerui, qemu-devel; +Cc: WANG Xuerui, Philippe Mathieu-Daudé, xtex
On 12/6/25 12:24, WANG Xuerui wrote:
> From: WANG Xuerui <git@xen0n.name>
>
> Support for TCGCond's in loongarch64 cmp_vec codegen is not uniform: NE
> is not supported at all and will trip over assertions, and legalization
> (currently just operand-swapping) is not done for reg-imm comparisons.
> Since the TCG middle-end will not legalize the comparison conditions for
> us, we have to do it ourselves like other targets.
>
> Because EQ/LT/LTU/LE/LEU are natively supported, we only have to keep
> the current operand swapping treatment for GT/GTU/GE/GEU but ensure it
> is done for both reg-reg and reg-imm cases, and use a bitwise NOT to
> help legalize NE.
>
> While at it, lift the cmp_vec handling to own function to make it easier
> for readers.
>
> Fixes: d8b6fa593d2d ("tcg/loongarch64: Lower cmp_vec to vseq/vsle/vslt")
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3237
> Cc: Richard Henderson <richard.henderson@linaro.org>
> Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
> Reported-by: xtex <xtex@aosc.io>
> Signed-off-by: WANG Xuerui <git@xen0n.name>
> ---
> tcg/loongarch64/tcg-target.c.inc | 119 +++++++++++++++++++------------
> 1 file changed, 75 insertions(+), 44 deletions(-)
>
> diff --git a/tcg/loongarch64/tcg-target.c.inc b/tcg/loongarch64/tcg-target.c.inc
> index 10c69211ac5..1a243a57beb 100644
> --- a/tcg/loongarch64/tcg-target.c.inc
> +++ b/tcg/loongarch64/tcg-target.c.inc
> @@ -2179,15 +2179,38 @@ static void tcg_out_addsub_vec(TCGContext *s, bool lasx, unsigned vece,
> tcg_out32(s, encode_vdvjvk_insn(insn, a0, a1, a2));
> }
>
> -static void tcg_out_vec_op(TCGContext *s, TCGOpcode opc,
> - unsigned vecl, unsigned vece,
> - const TCGArg args[TCG_MAX_OP_ARGS],
> - const int const_args[TCG_MAX_OP_ARGS])
> +static void tcg_out_cmp_vec(TCGContext *s, bool lasx, unsigned vece,
> + TCGArg a0, TCGArg a1, TCGArg a2,
> + bool a2_is_const, TCGCond cond)
> {
> - TCGType type = vecl + TCG_TYPE_V64;
> - bool lasx = type == TCG_TYPE_V256;
> - TCGArg a0, a1, a2, a3;
> LoongArchInsn insn;
> + bool need_invert = false;
> +
> + switch (cond) {
> + case TCG_COND_EQ:
> + case TCG_COND_LE:
> + case TCG_COND_LEU:
> + case TCG_COND_LT:
> + case TCG_COND_LTU:
> + /* These are directly expressible. */
> + break;
> + case TCG_COND_NE:
> + need_invert = true;
> + cond = TCG_COND_EQ;
> + break;
> + case TCG_COND_GE:
> + case TCG_COND_GEU:
> + case TCG_COND_GT:
> + case TCG_COND_GTU:
> + {
> + TCGArg t;
> + t = a1, a1 = a2, a2 = t;
> + cond = tcg_swap_cond(cond);
> + break;
> + }
You can't just swap if a2_is_const.
You can get better results by using tcg_expand_vec_op() to transform the comparison early.
You probably want to do something like s390x, where you have a helper that transforms the
comparision but without the inversion for NE, and then applies the inversion for
INDEX_op_cmp_vec and swaps operands for INDEX_op_cmpsel_vec.
r~
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