diff options
Diffstat (limited to 'gcc/tree-ssa-forwprop.cc')
| -rw-r--r-- | gcc/tree-ssa-forwprop.cc | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc index 68e80ba..79ac25f 100644 --- a/gcc/tree-ssa-forwprop.cc +++ b/gcc/tree-ssa-forwprop.cc @@ -216,6 +216,31 @@ 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) @@ -5177,7 +5202,7 @@ pass_forwprop::execute (function *fun) } if (all_same) { - if (may_propagate_copy (res, first)) + if (forwprop_may_propagate_copy (res, first)) to_remove_defs.safe_push (SSA_NAME_VERSION (res)); fwprop_set_lattice_val (res, first); } @@ -5532,7 +5557,7 @@ pass_forwprop::execute (function *fun) { if (!is_gimple_debug (stmt)) bitmap_set_bit (simple_dce_worklist, SSA_NAME_VERSION (use)); - if (may_propagate_copy (use, val)) + if (forwprop_may_propagate_copy (use, val)) { propagate_value (usep, val); substituted_p = true; @@ -5695,7 +5720,7 @@ pass_forwprop::execute (function *fun) /* If we can propagate the lattice-value mark the stmt for removal. */ if (val != lhs - && may_propagate_copy (lhs, val)) + && forwprop_may_propagate_copy (lhs, val)) to_remove_defs.safe_push (SSA_NAME_VERSION (lhs)); fwprop_set_lattice_val (lhs, val); } @@ -5717,7 +5742,7 @@ pass_forwprop::execute (function *fun) continue; tree val = fwprop_ssa_val (arg); if (val != arg - && may_propagate_copy (arg, val, !(e->flags & EDGE_ABNORMAL))) + && forwprop_may_propagate_copy (arg, val, !(e->flags & EDGE_ABNORMAL))) propagate_value (use_p, val); } |