https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60172
--- Comment #16 from Thomas Preud'homme <thomas.preudhomme at arm dot com> --- Hi Richard, could you expand on what you said in comment #13? I don't see how reassoc could help cse here. From what I understood, reassoc tries to group per rank. In our case, we have (view of the source with loop unrolling): Arr_2_Par_Ref [Int_Loc] [Int_Loc] = Int_Loc; /* some stmts */ Arr_2_Par_Ref [Int_Loc+10] [Int_Loc] = Arr_1_Par_Ref [Int_Loc]; If I'm not mistaken, in the first case you'd have: Int_Loc * 4 Int_Loc * 100 Arr_2_Par_Ref that would be added together with several statements. However in the second case you'd have: Int_Loc * 4 Int_Loc * 100 1000 Arr_2_Par_Ref that would be added together with several statements. I don't see how could 1000 being added first or last, it seems to me that it's always going to be in an intermediate statement and thus not all redanduncy would be eliminated by CSE. Please let me know if my reasonning is flawed so that I can progress toward a solution.
