Suppose I have the following C line:

int a = 4   7;

When compiling this line, GCC will always produce something like mov DWORD PTR [rbp-X], 0xb, as the result of this computation is constant and known at compile time. Is there a way to disable this behaviour to have a mov 4, add 7 instead?

A quick search led me to the -O0 or -OG flags, but they turn off other kinds of optimizations, such as the fact that functions should be aligned in memory.

CodePudding user response：

Is there a way to disable this behaviour to have a mov 4, add 7 instead?

No. Evaluation of elementary constant expressions is built into the compiler.