Hi, 1) I think these are the passes of gcc. source->generic->gimple->SSA->rtl->assembly. Am I right? 2)http://www.ugcs.caltech.edu/manuals/lang/gcc-3.2.2-internals/gccint_30.html#SEC30 This link tells about some of passes and some of optimizations done in each passes. Where can I get more information? Thanks in advance. ___________________________________________________________ Inbox full of unwanted email? Get leading protection and 1GB storage with All New Yahoo! Mail. http://uk.docs.yahoo.com/nowyoucan.html