diydrones/PX4Firmware — pull request #1 by geeksville (2013-05-28 04:28:35+00:00)
Title: Make -Os the default optimization parameter (rather than -O3)

Saves 64K in .text size (640K -> 580K), the CPU is quite fast and the
1MB flash is a potentially scarce resource.

On a particular project basis, just do OPTIMIZE = $(OPTIMIZE_MAX) for
best speed.