Different behavior between native and WASM

[MCMocoder]

Version:

emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.0.2-git
clang version 14.0.0 (https://github.com/llvm/llvm-project.git 1a929525e86a20d0b3455a400d0dbed40b325a13)
Target: wasm32-unknown-emscripten
Thread model: posix
InstalledDir: /usr/local/opt/emscripten/libexec/llvm/bin

Platform: MacOS Big Sur 11.0.1

Native Compiler Version:

clang version 13.0.0
Target: x86_64-apple-darwin20.1.0
Thread model: posix
InstalledDir: /usr/local/bin

When I compile the following code with my compiler,I get different results.

i=0
j=0
DO
IF i<j THEN 
i=i+1
END IF
LOOP UNTIL i>j
END

If I use native executable as the compiler , it can be successfully compiled.
If I use WASM to compile , it will throw errors.
I used this command to compile:

em++ ../src/compile.cc ../src/lex/lexer.cc ../src/parse/parse.cc ../src/bm3.cc -O3 --no-entry -I../include -o -WASM=0 -o compiler.js -fwasm-exceptions -s EXPORTED_FUNCTIONS=_main

The repo is here:github.com/MCMocoder/BM3-Mathbasic

[kripken]

it will throw errors.

Internal errors in your program? Or wasm ones - if so, which?

Overall the first thing I would try for a situation like this is the sanitizers. The program may be affected by undefined behavior.

https://emscripten.org/docs/debugging/Sanitizers.html

If that doesn't help, debugging the program to where it diverges from a native build is the next step.