Get Assembly code after every optimization GCC makes?

Question

From Optimization Compiler on Wikipedia,

Compiler optimization is generally implemented using a sequence of optimizing transformations

Answer 1

Compile with switch -S to get the assembly code. This should work for any level of optimization. For instance, to get the assembly code generated in O2 mode, try:

    g++/gcc -S -O2 input.cpp

a corresponding input.s will be generated, which contains the assembly code generated. Repeat this for any optimization level you want.