On 9/18/07, Jim Wilson <[EMAIL PROTECTED]> wrote: > Tomas Svensson wrote: > There is no optimization at all without -O, no matter how many -f > options you use. What you want to do is -O -fno-foo -fno-bar etc. > However, we do not have -f options for every optimization, so there is > no guarantee that this will identify the optimization pass that exposes > the bug in your port.
Right, thanks. I sure hope I learn from all these silly mistakes... Anyway, I did the same thing again, this time with starting with the -O2 that causes the problem and turning off options with -fno- flags. This time, I found the compilation to work with '-O2 -fno-gcse' but to break with just '-O2'. So I guess the problem is somehow caused by global common subexpression elimination. Could it be that gcse changes the insn in some way, making it unrecognizable by the usual define_insn's? Should I use (unspec ..) or (clobber ..) instead of (use ..) (as suggested in GCC Internals, Side effects)? If so, what is the difference, really?
