C++ compiler optimisations (MSYS2 MinGW-64 bit GCC compiler used with VSCode) - c++

Question

I'm trying to apply the different optimisation levels (-O0, -O1, -O2, -O3 and so on) to the compilation and execution of a .cpp file.
However, I can't figure out the exact syntax I need to use and where to write the instructions (i.e. in which terminal, the VSCode terminal or the MinGW terminal)?
Any help would be much appreciated.
tasks.json:
{
"tasks": [
{
"type": "cppbuild",
"label": "C/C++: g++.exe build active file",
"command": "C:\\msys64\\mingw64\\bin\\g++.exe",
"args": [
"-g",
"${file}",
"-o",
"${fileDirname}\\${fileBasenameNoExtension}.exe"
],
"options": {
"cwd": "${fileDirname}"
},
"problemMatcher": [
"$gcc"
],
"group": {
"kind": "build",
"isDefault": true
},
"detail": "Task generated by Debugger."
},
{
"type": "cppbuild",
"label": "C/C++: cpp.exe build active file",
"command": "C:\\msys64\\mingw64\\bin\\cpp.exe",
"args": [
"-g",
"${file}",
"-o",
"${fileDirname}\\${fileBasenameNoExtension}.exe"
],
"options": {
"cwd": "${fileDirname}"
},
"problemMatcher": [
"$gcc"
],
"group": "build",
"detail": "compiler: C:\\msys64\\mingw64\\bin\\cpp.exe"
}
],
"version": "2.0.0"
}

Answer 1

In this field:
"args": [
"-g",
"${file}",
"-o",
"${fileDirname}\\${fileBasenameNoExtension}.exe"
],
add the optimization option:
"args": [
"-g",
"${file}",
"-o",
"${fileDirname}\\${fileBasenameNoExtension}.exe",
"-O2"
],
Consider that you have two tasks (I am not sure why you have the second one) and you need to set it in the correct task. If I were you I would remove the unused one and instead create a task for debug and release build: Release build in Visual Studio Code
Be careful that this is about c# and cannot be copy pasted!