> This improves value-numbering of calls that read memory, calls > to const functions with aggregate arguments and calls to > pure functions where the latter include const functions we > demoted to pure for the fear of interposing with a less > optimized version. Note that for pure functions we do not > handle functions that access global memory.
Thank you! I am happy we finally undid some of the pessimization caused by the interposition panic. I was wondering if I should try next stage1 start tracking eliminated reads in functions, but that is tricky to do since things like if (*global_var == *globa_var) is folded already in frontend. I was thinking a bit what to do abou global accesses and I think we still can do something (also next stage1). Currently we disambiguate using if (stmt_may_clobber_ref_p_1 (def, &ref, true)) where ref is the REF is a ao_ref we built from the summary of STMT and DEF is another statement. This is fine but we ignore info we have from PTA on STMT (the statement we try to optimize). I we could look at DEF, and try to disambiguate all memory it writes against STMT using PTA oracle and that would let us to handle global memory well (we don't need REF for that) because we will work out that some accesses are not escaping to STMT becaue they are not in CALLUSED. Somewhat anoying is that we don't have predicate in tree-ssa-alias for that (stmt_clobber_stmt_p :) Honza
