compiler-optimization

I'm learning C++ and I came across the -fno-elide-constructors , below I have included the description from the man page. -fno-elide-constructors The C++ standard allows an implementation to omit creating a temporary which is only used to initialize another object of the same type. Specifying this option disables that optimization, and forces G++ to call the copy constructor in all cases. So with this option I am able disable this particular type of compiler optimization. I have a program that creates 2 objects and adds them together and prints when each of the function is called using using

I'm doing a presentation in few months about .Net performance and optimization, I wanted to provide some samples of unnecessary optimization, things that will be done by the compiler anyways. where can I find some explanation on what optimizations the compiler is actually capable of maybe some before and after code? check out these links C# Compiler Optimizations compiler optimization msdn Also checkout this book on MSIL 1. Microsoft Intermediate Language: Comparison Between C# and VB.NET / Niranjan Kumar What I think would be even better than examples of "things that will be done by the

In order to know how exactly the gcc do the optimization, I have written two program compiling with -O2, but there is some difference of the assembly code. In my programs, I want to output "hello" in the loop, and add some delay between each output. These two programs are only for illustrating my question, and I know I can using volatile or asm in program 1 to achieve my purpose. Program 1 #include <stdio.h> int main(int argc, char **argv) { unsigned long i = 0; while (1) { if (++i > 0x1fffffffUL) { printf("hello\n"); i = 0; } } } Compile with -O2, the assembly code is: Disassembly of section