This small patch just changes around the code slightly to make it easier to understand that the cases were handling diamond shaped BB for both do_store_elim/do_hoist_loads. There is no effect on code output at all since all of the checks are the same still.
Note this depends on https://gcc.gnu.org/pipermail/gcc-patches/2023-April/616241.html as that allows this to be done. OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. gcc/ChangeLog: * tree-ssa-phiopt.cc (tree_ssa_phiopt_worker): Change the code around slightly to move diamond handling for do_store_elim/do_hoist_loads out of the big if/else. --- gcc/tree-ssa-phiopt.cc | 46 +++++++++++++++++++----------------------- 1 file changed, 21 insertions(+), 25 deletions(-) diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc index 8c5c8d8c250..d886c88215b 100644 --- a/gcc/tree-ssa-phiopt.cc +++ b/gcc/tree-ssa-phiopt.cc @@ -175,28 +175,38 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p) std::swap (bb1, bb2); std::swap (e1, e2); } - else if (do_store_elim - && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) + else if (EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) + { + diamond_p = true; + e2 = EDGE_SUCC (bb2, 0); + } + else + continue; + + e1 = EDGE_SUCC (bb1, 0); + + /* Make sure that bb1 is just a fall through. */ + if (!single_succ_p (bb1) + || (e1->flags & EDGE_FALLTHRU) == 0) + continue; + + if (do_store_elim && diamond_p) { - basic_block bb3 = EDGE_SUCC (bb1, 0)->dest; + basic_block bb3 = e1->dest; - if (!single_succ_p (bb1) - || (EDGE_SUCC (bb1, 0)->flags & EDGE_FALLTHRU) == 0 - || !single_succ_p (bb2) - || (EDGE_SUCC (bb2, 0)->flags & EDGE_FALLTHRU) == 0 + if (!single_succ_p (bb2) + || (e2->flags & EDGE_FALLTHRU) == 0 || EDGE_COUNT (bb3->preds) != 2) continue; if (cond_if_else_store_replacement (bb1, bb2, bb3)) cfgchanged = true; continue; } - else if (do_hoist_loads - && EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) + else if (do_hoist_loads && diamond_p) { - basic_block bb3 = EDGE_SUCC (bb1, 0)->dest; + basic_block bb3 = e1->dest; if (!FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (cond_stmt))) - && single_succ_p (bb1) && single_succ_p (bb2) && single_pred_p (bb1) && single_pred_p (bb2) @@ -209,20 +219,6 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p) hoist_adjacent_loads (bb, bb1, bb2, bb3); continue; } - else if (EDGE_SUCC (bb1, 0)->dest == EDGE_SUCC (bb2, 0)->dest) - { - diamond_p = true; - e2 = EDGE_SUCC (bb2, 0); - } - else - continue; - - e1 = EDGE_SUCC (bb1, 0); - - /* Make sure that bb1 is just a fall through. */ - if (!single_succ_p (bb1) - || (e1->flags & EDGE_FALLTHRU) == 0) - continue; if (do_store_elim && !diamond_p) { -- 2.31.1
