Unexpected execution result on fast interpreter mode

[erxiaozhou]

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Subject of the issue

The WAMR on faster interpreter mode has a wrong execution result on the test case.

Test case

tt.zip

(module
  (type (;0;) (func))
  (type (;1;) (func (result i32)))
  (type (;2;) (func (param i32 i32) (result i32 i32)))
  (func (;0;) (type 1) (result i32)
    f32.const -0x1.0bb6d6p+2 (;=-4.18303;)
    f32.const -0x1.2a640ap+2 (;=-4.66236;)
    f32.ge
    i32.const 353
    call 1
    i32.const 0
    if (param i32 i32) (result i32 i32)  ;; label = @1
    end
    i32.gt_u
    return
    )
  (func (;1;) (type 2) (param i32 i32) (result i32 i32)
    i32.const -1
    i32.const 2147483647)
  (export "_start" (func 0))
  (export "to_test" (func 0)))

Your environment

• Host OS: Ubuntu 20.04
• Commit Id: 835188cc53373159165423debc48242ad15548d6

Steps to reproduce

1. build WAMR in fast interpreter mode
2. execute the command

iwasm --heap-size=0 -f "to_test" <test_case>

Expected behavior

1

Actual behavior

0

[wenyongh]

@erxiaozhou thanks for reporting the issue, it is mainly caused by the handling of an if block without else opcode for fast interpreter:

    if (param i32 i32) (result i32 i32)  ;; label = @1
    end

I submitted PR #3404 to fix it, please try again.