UNREACHABLE Trap in `v128.load8_splat` with memidx ≠ 0

[akldc]

Test Case

(module
  (type $0 (struct (field (mut f32))))
  (type $1 (func (result v128 (ref 0))))
  (type $2 (func (result v128 f32)))
  (type $3 (func (param v128 (ref 0)) (result v128 f32)))
  (type $4 (func (result v128 i32)))
  (memory $0 1 2)
  (memory $1 1 1)
  (export "f0" (func 0))
  (export "f1" (func 1))
  (func $0
    (type 1)
    (local i64)
    (i32.const 2)
    (v128.load8_splat 1 offset=2)
    (struct.new_default 0)
  )
  (func $1 
    (type 4)   
    (call 0)
    (ref.is_null)
  )
)

Description

Executing the above case will result in the following error.

$ wizeng.x86-64-linux --print-result=true --invoke=f1 test1.wasm
<wasm func "1"> +1
  <wasm func "0"> +12
    !trap[UNREACHABLE]

Set the parameter of v128.load8_splat to 0 (i.e., v128.load8_splat 0 offset=2) to obtain the correct result.

$ wizeng.x86-64-linux --print-result=true --invoke=f1 test1.wasm
v128:0000000000000000_0000000000000000 0

v128.load8_splat appears to mishandle non-zero memory indices; using memidx = 1 causes an UNREACHABLE trap, while memidx = 0 works correctly.

Environment

Wizard Engine 25β.2902
Ubuntu 20.04