measure the time of execution for different compiler optimization options (eg. O0 and O3) code example

Example: measure the time of execution for different compiler optimization options (eg. O0 and O3)

-fgcse-after-reload 
-fipa-cp-clone
-floop-interchange 
-floop-unroll-and-jam 
-fpeel-loops 
-fpredictive-commoning 
-fsplit-loops 
-fsplit-paths 
-ftree-loop-distribution 
-ftree-loop-vectorize 
-ftree-partial-pre 
-ftree-slp-vectorize 
-funswitch-loops 
-fvect-cost-model 
-fvect-cost-model=dynamic 
-fversion-loops-for-strides