diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/testsuite/gcc.dg/torture/pr115388.c | 34 | ||||
| -rw-r--r-- | gcc/tree-ssa-dse.cc | 61 |
2 files changed, 74 insertions, 21 deletions
diff --git a/gcc/testsuite/gcc.dg/torture/pr115388.c b/gcc/testsuite/gcc.dg/torture/pr115388.c new file mode 100644 index 0000000..c7c9028 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr115388.c @@ -0,0 +1,34 @@ +/* { dg-do run } */ + +int printf(const char *, ...); +int a[10], b, c, d[0], h, i, j, k, l; +char e = -1, g; +volatile int f; +static void n() { + while (e >= 0) + while (1) + ; + for (b = 2; b >= 0; b--) { + for (k = 0; k < 4; k++) { + if (e || i) + continue; + for (h = 0; h < 2; h++) + f; + } + for (l = 2; l >= 0; l--) + g = 0; + for (; g < 1; g++) + if (c) + d[l] = 1; + a[9] = 0; + a[b] = 1; + while (j) + printf("\n"); + } +} +int main() { + n(); + if (a[1] != 1) + __builtin_abort(); + return 0; +} diff --git a/gcc/tree-ssa-dse.cc b/gcc/tree-ssa-dse.cc index 9252ca3..63bf449 100644 --- a/gcc/tree-ssa-dse.cc +++ b/gcc/tree-ssa-dse.cc @@ -1018,8 +1018,11 @@ dse_classify_store (ao_ref *ref, gimple *stmt, if (defvar == stop_at_vuse) return DSE_STORE_LIVE; - FOR_EACH_IMM_USE_STMT (use_stmt, ui, defvar) + use_operand_p usep; + FOR_EACH_IMM_USE_FAST (usep, ui, defvar) { + use_stmt = USE_STMT (usep); + /* Limit stmt walking. */ if (++cnt > param_dse_max_alias_queries_per_store) { @@ -1031,31 +1034,43 @@ dse_classify_store (ao_ref *ref, gimple *stmt, have to be careful with loops and with memory references containing operands that are also operands of PHI nodes. See gcc.c-torture/execute/20051110-*.c. */ - if (gimple_code (use_stmt) == GIMPLE_PHI) + if (gphi *phi = dyn_cast <gphi *> (use_stmt)) { /* Look through single-argument PHIs. */ - if (gimple_phi_num_args (use_stmt) == 1) - worklist.safe_push (gimple_phi_result (use_stmt)); - - /* If we already visited this PHI ignore it for further - processing. */ - else if (!bitmap_bit_p (visited, - SSA_NAME_VERSION - (PHI_RESULT (use_stmt)))) + if (gimple_phi_num_args (phi) == 1) + worklist.safe_push (gimple_phi_result (phi)); + else { /* If we visit this PHI by following a backedge then we have to make sure ref->ref only refers to SSA names that are invariant with respect to the loop - represented by this PHI node. */ - if (dominated_by_p (CDI_DOMINATORS, gimple_bb (stmt), - gimple_bb (use_stmt)) - && !for_each_index (ref->ref ? &ref->ref : &ref->base, - check_name, gimple_bb (use_stmt))) - return DSE_STORE_LIVE; - defs.safe_push (use_stmt); - if (!first_phi_def) - first_phi_def = as_a <gphi *> (use_stmt); - last_phi_def = as_a <gphi *> (use_stmt); + represented by this PHI node. We handle irreducible + regions by relying on backedge marking and identifying + the head of the (sub-)region. */ + edge e = gimple_phi_arg_edge + (phi, PHI_ARG_INDEX_FROM_USE (usep)); + if (e->flags & EDGE_DFS_BACK) + { + basic_block rgn_head + = nearest_common_dominator (CDI_DOMINATORS, + gimple_bb (phi), + e->src); + if (!for_each_index (ref->ref + ? &ref->ref : &ref->base, + check_name, rgn_head)) + return DSE_STORE_LIVE; + } + /* If we already visited this PHI ignore it for further + processing. But note we have to check each incoming + edge above. */ + if (!bitmap_bit_p (visited, + SSA_NAME_VERSION (PHI_RESULT (phi)))) + { + defs.safe_push (phi); + if (!first_phi_def) + first_phi_def = phi;; + last_phi_def = phi; + } } } /* If the statement is a use the store is not dead. */ @@ -1681,7 +1696,11 @@ pass_dse::execute (function *fun) /* Dead store elimination is fundamentally a reverse program order walk. */ int *rpo = XNEWVEC (int, n_basic_blocks_for_fn (fun) - NUM_FIXED_BLOCKS); - int n = pre_and_rev_post_order_compute_fn (fun, NULL, rpo, false); + auto_bitmap exit_bbs; + bitmap_set_bit (exit_bbs, EXIT_BLOCK); + edge entry = single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (fun)); + int n = rev_post_order_and_mark_dfs_back_seme (fun, entry, + exit_bbs, false, rpo, NULL); for (int i = n; i != 0; --i) { basic_block bb = BASIC_BLOCK_FOR_FN (fun, rpo[i-1]); |