Reducing the execution time of the code using CLANG/LLVM compiler

Well... When i was searching for a good compiler I came across clang/LLVM. This compiler gives me same result as other compilers like icc, pgi. But the problem is there are very few tuto开发者_StackOverflow中文版rials on this compiler... Kindly let me know where can I find the tutorials on the clang compiler.

Note by: I have compiled my c code using the following flags clang -O3 -mfpmath=sse file.c

Clang (the command line compiler) takes gcc-compatible options, but accepts and ignores a lot of flags that GCC takes (like -mfpmath=sse). We aim to generate good code out of the box. There are some flags that allow clang to violate the language standards that can be useful in some scenarios, like -ffast-math though.

If you're looking for good performance, I highly recommend experimenting with link-time-optimization, which allows clang to optimize across source files in your application. Depending on what platform you're on, this is enabled by passing -O4 to the compiler. If you're on linux, you need to use the "gold" linker (see http://llvm.org/docs/GoldPlugin.html). If you're on the mac, it should "just work" with any recent version of Xcode.

The clang is not a compiler, it is just frontend of LLVM compiler. So, when you calls clang, it parses c/c++ file but the optimization and code generation is handled in LLVM itself.

Here you can found a documentation of LLVM optimization and analysis options: http://llvm.org/docs/Passes.html

The full documentation is here http://llvm.org/docs/

Also useful options are listed here http://linux.die.net/man/1/llvmc (I suggest clang will accept most of them too)