Obtaining current GCC architecture

Question

How can I find out what the -march default argument is for the current architecture if I don\'t supply any?

Answer 1

I found this gem on the GCC mailing list that prints the default -march and mtune parameters:

$ echo | gcc -v -E - 2>&1 | grep cc1
 /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.0/cc1 -E -quiet -v - -mtune=generic -march=x86-64

Basically, you are compiling an empty file from stdin and while doing so, you print the commands.