Homework 1

1.

On any machine of your choice, checkout the latest LLVM, Clang, and Compiler-RT sources from subversion following the directions here:

http://clang.llvm.org/get_started.html Links to an external site.

Configure for a Release build. Build LLVM and Clang.

HANDIN: the output of "clang -v" for the version of clang you built

2.

Checkout the latest GCC sources from subversion. Configure and build GCC. Follow the instructions here: 

https://gcc.gnu.org/install/index.html Links to an external site.

HANDIN: the output of "gcc -v" for the version of gcc you built

3.

Using the GCC explorer:

http://gcc.godbolt.org/ Links to an external site.

Select x86-64 clang 3.8 as the compiler. Write a C or C++ function that, when compiled at -O2, isn't fully optimized. Describe (in a comment below the source code) the missed optimization and also provide the fully optimized assembly code that the compiler should have generated.

HANDIN: a shortlink into GCC explorer so I can look at your code, explanation, and optimal assembly

4.

repeat #3, but with GCC 6.1 as the compiler. Make sure the C or C++ function is different from the one you hand in for #3