===================================================================
@@ -3381,6 +3381,11 @@
edge_iterator ei;
edge e;
+ /* Before inlining we do not want to optimize away clobbers that may become
+ internal when inlined. */
+ if (optimize && !cfun->after_inlining)
+ return;
+
/* Only optimize anything if the bb contains at least one clobber,
ends with resx (checked by caller), optionally contains some
debug stmts or labels, or at most one __builtin_stack_restore
===================================================================
@@ -2347,6 +2347,56 @@
return NULL;
}
+/* Return true when the basic blocks contains only clobbers followed by RESX.
+ Such BBs are kept around to make removal of dead stores possible with
+ presence of EH and will be optimized out by optimize_clobbers later in the
+ game.
+
+ NEED_EH is used to recurse in case the clobber has non-EH predecestors
+ that can be clobber only, too.. When it is false, the RESX is not necessary
+ on the end of basic block. */
+
+static bool
+clobber_only_eh_bb_p (basic_block bb, bool need_eh = true)
+{
+ gimple_stmt_iterator gsi = gsi_last_bb (bb);
+ edge_iterator ei;
+ edge e;
+
+ if (need_eh)
+ {
+ if (gsi_end_p (gsi))
+ return false;
+ if (gimple_code (gsi_stmt (gsi)) != GIMPLE_RESX)
+ return false;
+ gsi_prev (&gsi);
+ }
+ else if (!single_succ_p (bb))
+ return false;
+
+ for (; !gsi_end_p (gsi); gsi_prev (&gsi))
+ {
+ gimple stmt = gsi_stmt (gsi);
+ if (is_gimple_debug (stmt))
+ continue;
+ if (gimple_clobber_p (stmt))
+ continue;
+ if (gimple_code (stmt) == GIMPLE_LABEL)
+ break;
+ return false;
+ }
+
+ /* See if all predecestors are either throws or clobber only BBs. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (!(e->flags & EDGE_EH)
+ && !clobber_only_eh_bb_p (e->src, false))
+ return false;
+
+ if (!need_eh)
+ debug_bb (bb);
+ return true;
+}
+
/* Compute function body size parameters for NODE.
When EARLY is true, we compute only simple summaries without
non-trivial predicates to drive the early inliner. */
@@ -2410,6 +2460,14 @@
{
bb = BASIC_BLOCK_FOR_FN (cfun, order[n]);
freq = compute_call_stmt_bb_frequency (node->decl, bb);
+ if (clobber_only_eh_bb_p (bb))
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "\n Ignoring BB %i;"
+ " it will be optimized away by cleanup_clobbers\n",
+ bb->index);
+ continue;
+ }
/* TODO: Obviously predicates can be propagated down across CFG. */
if (parms_info)