https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115248
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- The first (major) difference in the IR (besides the original removal of statements) come from threadfull1. trunk: ``` Registering killing_def (path_oracle) distbb_72 Registering killing_def (path_oracle) distij_71 Registering killing_def (path_oracle) x_70 Registering killing_def (path_oracle) _15 folding with relation x_70 == x_70 Checking profitability of path (backwards): [10] Registering jump thread: (16, 18) incoming edge; (18, 20) nocopy; path: 16->18->20 SUCCESS Checking profitability of path (backwards): bb:20 (4 insns) bb:18 Control statement insns: 2 Overall: 2 insns ``` Before: ``` Registering killing_def (path_oracle) distbb_73 Registering killing_def (path_oracle) distij_72 Registering killing_def (path_oracle) x_71 Registering killing_def (path_oracle) _15 folding with relation x_71 == x_71 Registering value_relation (path_oracle) (elcdst_35 <= distbb_73) (root: bb16) path: 16->18->xx REJECTED Checking profitability of path (backwards): bb:18 (2 insns) bb:16 (6 insns) bb:23 Control statement insns: 2 Overall: 6 insns Registering killing_def (path_oracle) _15 Registering killing_def (path_oracle) x_71 Registering killing_def (path_oracle) distij_72 folding with relation x_71 == x_71 Registering killing_def (path_oracle) distbb_73 Registering value_relation (path_oracle) (elcdst_35 <= distbb_73) (root: bb23) path: 23->16->18->xx REJECTED Checking profitability of path (backwards): bb:18 (2 insns) bb:16 (6 insns) bb:23 (2 insns) bb:15 Control statement insns: 2 Overall: 8 insns FAIL: Did not thread around loop and would copy too many statements. Checking profitability of path (backwards): bb:18 (2 insns) bb:16 (6 insns) bb:23 (2 insns) bb:22 (latch) Control statement insns: 2 Overall: 8 insns FAIL: Did not thread around loop and would copy too many statements. Checking profitability of path (backwards): bb:20 (4 insns) bb:18 Control statement insns: 2 Overall: 2 insns ``` I don't understand how if the IR coming in is basically the same (just different underlying decl for the ssa_name) would make a difference like this. Seems like there is some costing difference for temporaries vs non-temporaries which should NOT happen.
