diff options
Diffstat (limited to 'gcc/tree-ssa-dce.c')
| -rw-r--r-- | gcc/tree-ssa-dce.c | 29 |
1 files changed, 14 insertions, 15 deletions
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c index 67d0472cc59..f0135a9c42d 100644 --- a/gcc/tree-ssa-dce.c +++ b/gcc/tree-ssa-dce.c @@ -325,7 +325,13 @@ mark_stmt_if_obviously_necessary (gimple stmt, bool aggressive) break; case GIMPLE_DEBUG: - mark_stmt_necessary (stmt, false); + /* Debug temps without a value are not useful. ??? If we could + easily locate the debug temp bind stmt for a use thereof, + would could refrain from marking all debug temps here, and + mark them only if they're used. */ + if (gimple_debug_bind_has_value_p (stmt) + || TREE_CODE (gimple_debug_bind_get_var (stmt)) != DEBUG_EXPR_DECL) + mark_stmt_necessary (stmt, false); return; case GIMPLE_GOTO: @@ -1071,7 +1077,7 @@ eliminate_unnecessary_stmts (void) { bool something_changed = false; basic_block bb; - gimple_stmt_iterator gsi; + gimple_stmt_iterator gsi, psi; gimple stmt; tree call; VEC (basic_block, heap) *h; @@ -1111,25 +1117,21 @@ eliminate_unnecessary_stmts (void) bb = VEC_pop (basic_block, h); /* Remove dead statements. */ - for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi);) + for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi = psi) { stmt = gsi_stmt (gsi); + psi = gsi; + gsi_prev (&psi); + stats.total++; /* If GSI is not necessary then remove it. */ if (!gimple_plf (stmt, STMT_NECESSARY)) { + if (!is_gimple_debug (stmt)) + something_changed = true; remove_dead_stmt (&gsi, bb); - something_changed = true; - - /* If stmt was the last stmt in the block, we want to - move gsi to the stmt that became the last stmt, but - gsi_prev would crash. */ - if (gsi_end_p (gsi)) - gsi = gsi_last_bb (bb); - else - gsi_prev (&gsi); } else if (is_gimple_call (stmt)) { @@ -1159,10 +1161,7 @@ eliminate_unnecessary_stmts (void) } notice_special_calls (stmt); } - gsi_prev (&gsi); } - else - gsi_prev (&gsi); } } |