diff options
Diffstat (limited to 'gcc/tree-ssa-forwprop.c')
| -rw-r--r-- | gcc/tree-ssa-forwprop.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c index df192952a1d..22d5f8443c9 100644 --- a/gcc/tree-ssa-forwprop.c +++ b/gcc/tree-ssa-forwprop.c @@ -34,6 +34,7 @@ along with GCC; see the file COPYING3. If not see #include "cfgloop.h" #include "optabs.h" #include "tree-ssa-propagate.h" +#include "gimple-ssa-combine.h" /* This pass propagates the RHS of assignment statements into use sites of the LHS of the assignment. It's basically a specialized @@ -3291,6 +3292,44 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi) return true; } +/* Delete possible dead code in BB which might have been caused + unused by ssa_combine until statement UNTIL. Return true if + a statement was removed. */ +static bool +delete_dead_code_uptil (gimple_stmt_iterator until) +{ + gimple_stmt_iterator gsi; + bool removed = false; + gsi = until; + gsi_prev (&gsi); + for (; !gsi_end_p (gsi);) + { + gimple stmt = gsi_stmt (gsi); + if (gimple_get_lhs (stmt) + && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME + && has_zero_uses (gimple_get_lhs (stmt)) + && !stmt_could_throw_p (stmt) + && !gimple_has_side_effects (stmt)) + { + gimple_stmt_iterator i2; + if (dump_file && dump_flags & TDF_DETAILS) + { + fprintf (dump_file, "Removing dead stmt "); + print_gimple_stmt (dump_file, stmt, 0, 0); + fprintf (dump_file, "\n"); + } + i2 = gsi; + gsi_prev (&gsi); + gsi_remove (&i2, true); + release_defs (stmt); + removed = true; + continue; + } + gsi_prev (&gsi); + } + return removed; +} + /* Main entry point for the forward propagation and statement combine optimizer. */ @@ -3299,6 +3338,7 @@ ssa_forward_propagate_and_combine (void) { basic_block bb; unsigned int todoflags = 0; + gimple_combine combiner; cfg_changed = false; @@ -3399,10 +3439,40 @@ ssa_forward_propagate_and_combine (void) { gimple stmt = gsi_stmt (gsi); bool changed = false; + tree new_expr = NULL_TREE; + bool temp = false; /* Mark stmt as potentially needing revisiting. */ gimple_set_plf (stmt, GF_PLF_1, false); + new_expr = combiner.combine (stmt); + if (new_expr) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Folding statement: "); + print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); + + print_generic_expr (dump_file, new_expr, TDF_SLIM); + fprintf (dump_file, "\n"); + } + if (replace_rhs_after_ssa_combine (&gsi, new_expr)) + { + cfg_changed = true; + if (delete_dead_code_uptil (gsi)) + todoflags |= TODO_remove_unused_locals; + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Replaced: "); + print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); + fprintf (dump_file, "\n"); + } + temp = true; + changed = true; + } + } + + if (!changed) switch (gimple_code (stmt)) { case GIMPLE_ASSIGN: @@ -3514,6 +3584,12 @@ ssa_forward_propagate_and_combine (void) default:; } + if (changed ? !temp : false) + { + fprintf (stderr, "\nStatement not folded by gimple_combine"); + print_gimple_stmt (stderr, stmt, 0, TDF_SLIM); + gcc_assert (false); + } if (changed) { /* If the stmt changed then re-visit it and the statements |