c - How can I compile to assembly with gcc

Question

How do I compile to assembly instead of an executable with gcc. I know there is an -S flag, but where do I use it in the makefile. For example, if I use flags -O3 -o exe_name, where should I put the -S flag?

question from:https://stackoverflow.com/questions/8021874/how-can-i-compile-to-assembly-with-gcc

Answer 1

I suggest also using -fverbose-asm because then the generated assembler has some generated comments which "explains" the code. For example:

gcc -S -fverbose-asm -O2 foo.c

would generate in foo.s (with some comments) the assembler code produced by compiling foo.c

And to understand what the GCC optimizations are doing one could even try -fdump-tree-all (but this produces hundreds of files!).