> > Yep, I am aware that tree hasing must match. I think my changes are safe so > > far: > > - ctors are already hashed resonably > > - types are not hashed so the changes strenghtening OEP_ADDRESS_OF are safe > > - OEP_ADDRESS_OF (so far) still boils down to syntactic matching. > > > > Looking at this I noticed that simple_cst_equal in tree.c seems to > > reimplement > > OEP_CONSTANT part of operand_equal_p and it seems to have bugs - i.e. not > > comparing index for CONSTRUCTOR ELTs. > > simple_cst_equal is also quite incomplete and I'd rather have it die...
My tought exactly. That three-state scheme may be useful (i.e. known equal/known different/unknown). I think we can adjust operand_equal_p to do that job quite easily and kill some other code duplication around . > > > Also I was always bit unsure how the path through operand_equal_p that > > allows > > different tree codes to match (stripping MEM_REF) and use of STRIP_NOPS > > combine > > with add_expr that doesn't do these. Do we have some mechanism that will > > prevent this from corrupting hashtables? > > We should ensure that equal trees get equal hash codes (heh, probably > easy to add a wrapper around operand_equal_p double-checking that). Yep, I tried that yesterday (some limited sanity checking is already done by gimplifier, but it misses cases). There are cases where hashing and operand_equal_p disagree. I suppose we can simply ignore MEM_REF and NOP_EXPR/CONVER_EXPR for hashing that gets things more into sync. It would be also nice to move the code to same location - with the plan to templatize operand_equal_p we could also templatize add_expr to same place. It is needed by ipa-icf at least. Honza > > Richard. > > > Honza > > > > > > Thanks, > > > Richard. > > > > > > > * fold-const.c (operand_equal_p): Drop types_compatible_p when > > > > comparing references. > > > > > > > > Index: fold-const.c > > > > =================================================================== > > > > --- fold-const.c (revision 229278) > > > > +++ fold-const.c (working copy) > > > > @@ -2982,9 +2982,6 @@ operand_equal_p (const_tree arg0, const_ > > > > TYPE_SIZE (TREE_TYPE (arg1)), > > > > flags))) > > > > return 0; > > > > - /* Verify that access happens in similar types. */ > > > > - if (!types_compatible_p (TREE_TYPE (arg0), TREE_TYPE > > > > (arg1))) > > > > - return 0; > > > > /* Verify that accesses are TBAA compatible. */ > > > > if (flag_strict_aliasing > > > > && (!alias_ptr_types_compatible_p > > > > > > > > > > > > > > -- > > > Richard Biener <rguent...@suse.de> > > > SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, > > > HRB 21284 (AG Nuernberg) > > > > > > -- > Richard Biener <rguent...@suse.de> > SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB > 21284 (AG Nuernberg)
