diff options
Diffstat (limited to 'gcc/tree-ssa-forwprop.cc')
| -rw-r--r-- | gcc/tree-ssa-forwprop.cc | 53 |
1 files changed, 24 insertions, 29 deletions
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc index 79ac25f..9a993ab 100644 --- a/gcc/tree-ssa-forwprop.cc +++ b/gcc/tree-ssa-forwprop.cc @@ -216,31 +216,6 @@ static bitmap to_purge; /* Const-and-copy lattice. */ static vec<tree> lattice; -/* forwprop_may_propagate_copy is like may_propagate_copy except - after the final folding, don't allow propagating of pointer ORIG - that have a lower alignment than the DEST name. - This is to prevent losing alignment information from - __builtin_assume_aligned for expand (See also PR 122086). */ -static bool -forwprop_may_propagate_copy (tree dest, tree orig, - bool dest_not_abnormal_phi_edge_p = false) -{ - if (!may_propagate_copy (dest, orig, dest_not_abnormal_phi_edge_p)) - return false; - - /* Only check alignment for the final folding. */ - if (!(cfun->curr_properties & PROP_last_full_fold)) - return true; - - /* Alignment only matters for pointer types. */ - if (!POINTER_TYPE_P (TREE_TYPE (dest)) || !POINTER_TYPE_P (TREE_TYPE (orig))) - return true; - - unsigned aligndest = get_pointer_alignment (dest); - unsigned alignorig = get_pointer_alignment (orig); - return aligndest <= alignorig; -} - /* Set the lattice entry for NAME to VAL. */ static void fwprop_set_lattice_val (tree name, tree val) @@ -1818,6 +1793,7 @@ do_simple_agr_dse (gassign *stmt, bool full_walk) /* Only handle clobbers of a full decl. */ if (!DECL_P (lhs)) return; + clobber_kind kind = (clobber_kind)CLOBBER_KIND (gimple_assign_rhs1 (stmt)); ao_ref_init (&read, lhs); tree vuse = gimple_vuse (stmt); unsigned limit = full_walk ? param_sccvn_max_alias_queries_per_access : 4; @@ -1839,6 +1815,25 @@ do_simple_agr_dse (gassign *stmt, bool full_walk) basic_block ubb = gimple_bb (use_stmt); if (stmt == use_stmt) continue; + /* If the use is the same kind of clobber for lhs, + then it can be safely skipped; this happens with eh + and sometimes jump threading. */ + if (gimple_clobber_p (use_stmt, kind) + && lhs == gimple_assign_lhs (use_stmt)) + continue; + /* If the use is a phi and it is single use then check if that single use + is a clobber of the same kind and lhs is the same. */ + if (gphi *use_phi = dyn_cast<gphi*>(use_stmt)) + { + use_operand_p ou; + gimple *ostmt; + if (single_imm_use (gimple_phi_result (use_phi), &ou, &ostmt) + && gimple_clobber_p (ostmt, kind) + && lhs == gimple_assign_lhs (ostmt)) + continue; + /* A phi node will never be dominating the clobber. */ + return; + } /* The use needs to be dominating the clobber. */ if ((ubb != bb && !dominated_by_p (CDI_DOMINATORS, bb, ubb)) || ref_maybe_used_by_stmt_p (use_stmt, &read, false)) @@ -5202,7 +5197,7 @@ pass_forwprop::execute (function *fun) } if (all_same) { - if (forwprop_may_propagate_copy (res, first)) + if (may_propagate_copy (res, first)) to_remove_defs.safe_push (SSA_NAME_VERSION (res)); fwprop_set_lattice_val (res, first); } @@ -5557,7 +5552,7 @@ pass_forwprop::execute (function *fun) { if (!is_gimple_debug (stmt)) bitmap_set_bit (simple_dce_worklist, SSA_NAME_VERSION (use)); - if (forwprop_may_propagate_copy (use, val)) + if (may_propagate_copy (use, val)) { propagate_value (usep, val); substituted_p = true; @@ -5720,7 +5715,7 @@ pass_forwprop::execute (function *fun) /* If we can propagate the lattice-value mark the stmt for removal. */ if (val != lhs - && forwprop_may_propagate_copy (lhs, val)) + && may_propagate_copy (lhs, val)) to_remove_defs.safe_push (SSA_NAME_VERSION (lhs)); fwprop_set_lattice_val (lhs, val); } @@ -5742,7 +5737,7 @@ pass_forwprop::execute (function *fun) continue; tree val = fwprop_ssa_val (arg); if (val != arg - && forwprop_may_propagate_copy (arg, val, !(e->flags & EDGE_ABNORMAL))) + && may_propagate_copy (arg, val, !(e->flags & EDGE_ABNORMAL))) propagate_value (use_p, val); } |