On Mon, 24 Jun 2019, Jan Hubicka wrote: > Hi, > as discussed on IRC today, after all this patch should be correct. I > have re-tested it with x86_64-linux in the following variant which also > moves load of ptrtype1 that is unnecesarily early. > > Bootstrapped/regtested x86_64-linux, OK?
OK. Richard. > * tree-ssa-alias.c (indirect_ref_may_alias_decl_p): Also give up > TBAA path when base2_alias_set is 0. > > Index: tree-ssa-alias.c > =================================================================== > --- tree-ssa-alias.c (revision 272614) > +++ tree-ssa-alias.c (working copy) > @@ -1458,10 +1466,8 @@ indirect_ref_may_alias_decl_p (tree ref1 > if (!flag_strict_aliasing || !tbaa_p) > return true; > > - ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); > - > /* If the alias set for a pointer access is zero all bets are off. */ > - if (base1_alias_set == 0) > + if (base1_alias_set == 0 || base2_alias_set == 0) > return true; > > /* When we are trying to disambiguate an access with a pointer dereference > @@ -1479,6 +1485,9 @@ indirect_ref_may_alias_decl_p (tree ref1 > if (base1_alias_set != base2_alias_set > && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) > return false; > + > + ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); > + > /* If the size of the access relevant for TBAA through the pointer > is bigger than the size of the decl we can't possibly access the > decl via that pointer. */
