on qemu we got an aborted error
**
ERROR:../target/loongarch/tcg/insn_trans/trans_vec.c.inc:3574:vldi_get_value: code should not be reached
Bail out! ERROR:../target/loongarch/tcg/insn_trans/trans_vec.c.inc:3574:vldi_get_value: code should not be reached
Aborted (core dumped)
but on 3A600/3A5000 we got a "Illegal instruction" error.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2971

Fixes: 29bb5d727ff ("target/loongarch: Implement vldi")
Signed-off-by: Song Gao <gaosong@loongson.cn>
---
 target/loongarch/tcg/insn_trans/trans_vec.c.inc | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/target/loongarch/tcg/insn_trans/trans_vec.c.inc b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
index dff92772ad..9d82d162a9 100644
--- a/target/loongarch/tcg/insn_trans/trans_vec.c.inc
+++ b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
@@ -3465,7 +3465,7 @@ TRANS(xvmsknz_b, LASX, gen_xx, gen_helper_vmsknz_b)
 static uint64_t vldi_get_value(DisasContext *ctx, uint32_t imm)
 {
     int mode;
-    uint64_t data, t;
+    uint64_t data = 0, t;
 
     /*
      * imm bit [11:8] is mode, mode value is 0-12.
@@ -3570,17 +3570,25 @@ static uint64_t vldi_get_value(DisasContext *ctx, uint32_t imm)
         }
         break;
     default:
-        generate_exception(ctx, EXCCODE_INE);
         g_assert_not_reached();
     }
     return data;
 }
 
+static bool check_vldi_mode(arg_vldi *a)
+{
+   return (a->imm >>8 & 0xf) <= 12;
+}
 static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
 {
     int sel, vece;
     uint64_t value;
 
+    if (!check_vldi_mode(a)){
+        generate_exception(ctx, EXCCODE_INE);
+        return true;
+    }
+
     if (!check_vec(ctx, oprsz)) {
         return true;
     }
-- 
2.34.1

On 4/6/25 10:40, Song Gao wrote:
> on qemu we got an aborted error
> **
> ERROR:../target/loongarch/tcg/insn_trans/trans_vec.c.inc:3574:vldi_get_value: code should not be reached
> Bail out! ERROR:../target/loongarch/tcg/insn_trans/trans_vec.c.inc:3574:vldi_get_value: code should not be reached
> Aborted (core dumped)
> but on 3A600/3A5000 we got a "Illegal instruction" error.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2971
> 
> Fixes: 29bb5d727ff ("target/loongarch: Implement vldi")
> Signed-off-by: Song Gao <gaosong@loongson.cn>
> ---
>   target/loongarch/tcg/insn_trans/trans_vec.c.inc | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/target/loongarch/tcg/insn_trans/trans_vec.c.inc b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> index dff92772ad..9d82d162a9 100644
> --- a/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> +++ b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> @@ -3465,7 +3465,7 @@ TRANS(xvmsknz_b, LASX, gen_xx, gen_helper_vmsknz_b)
>   static uint64_t vldi_get_value(DisasContext *ctx, uint32_t imm)
>   {
>       int mode;
> -    uint64_t data, t;
> +    uint64_t data = 0, t;
>   
>       /*
>        * imm bit [11:8] is mode, mode value is 0-12.
> @@ -3570,17 +3570,25 @@ static uint64_t vldi_get_value(DisasContext *ctx, uint32_t imm)
>           }
>           break;
>       default:
> -        generate_exception(ctx, EXCCODE_INE);
>           g_assert_not_reached();
>       }
>       return data;
>   }
>   
> +static bool check_vldi_mode(arg_vldi *a)
> +{
> +   return (a->imm >>8 & 0xf) <= 12;

Preferably (as easier to review):

       return extract32(a->imm, 8, 4) <= 12;

Otherwise patch LGTM :)

> +}
>   static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
>   {
>       int sel, vece;
>       uint64_t value;
>   
> +    if (!check_vldi_mode(a)){
> +        generate_exception(ctx, EXCCODE_INE);
> +        return true;
> +    }
> +
>       if (!check_vec(ctx, oprsz)) {
>           return true;
>       }