问题
I'm using QtCreator in Windows 7.
I want to configure it to use third level optimization (-O3) for c++ compiler.
How can I do this to speed up my code and what changes are necessary?
回答1:
Try to add next lines to your .pro file:
# remove possible other optimization flags
QMAKE_CXXFLAGS_RELEASE -= -O
QMAKE_CXXFLAGS_RELEASE -= -O1
QMAKE_CXXFLAGS_RELEASE -= -O2
# add the desired -O3 if not present
QMAKE_CXXFLAGS_RELEASE *= -O3
回答2:
Add these line's to your .pro file if you want a small application size
QMAKE_CXXFLAGS += -Os -mpreferred-stack-boundary=2 -finline-small-functions -momit-leaf-frame-pointer
If you want a faster application , consider using -O2 instead of -Os
refer this for more options
来源：https://stackoverflow.com/questions/12785364/configuration-for-optimizing-qtcreator-compiler