On Thu, May 20, 2010 at 2:09 PM, Ian Lance Taylor <i...@google.com> wrote: > Steven Bosscher <stevenb....@gmail.com> writes: > >> And finally: expand. This should be just a change of IR format, from >> GIMPLE to RTL. I have no idea why this pass always shows up in the top >> 10 of slowest parts of GCC. Lowering passes on e.g. WHIRL, or GENERIC >> lowering to GIMPLE, never show up in the compile time overviews. > > expand unfortunately does more than just convert IR. It also does > things like changing division by a constant into multiplication by a > constant, and changing multiplication by a constant into a set of > shifts and adds. It does various optimizations involving store flags > (a = b == c;). When expanding function calls, it generates > instructions to put arguments in the right place in registers and on > the stack. Etc.
stack variable overlay and stack slot assignments is here too. David > > Ian >
