#pragma push , is not supported by ARM Compiler 6, what should I do ?

void function1(void){
... // Optimized at O1 (from armcc -O1)
}
#pragma push
#pragma O3
void function2(void){
... // Optimized at O3
}
#pragma pop
void function3(void){
... // Optimized at O1 (from armcc -O1)
}

How do we find an alternative way?