--- old/src/share/vm/opto/gcm.cpp 2021-04-28 19:35:14.011346782 +0800 +++ new/src/share/vm/opto/gcm.cpp 2021-04-28 19:35:13.893342142 +0800 @@ -117,6 +117,9 @@ } +static bool is_dominator(Block* d, Block* n) { + return d->dom_lca(n) == d; +} //------------------------------schedule_pinned_nodes-------------------------- // Set the basic block for Nodes pinned into blocks void PhaseCFG::schedule_pinned_nodes(VectorSet &visited) { @@ -137,6 +140,41 @@ Block* block = get_block_for_node(input); // Basic block of controlling input schedule_node_into_block(node, block); } + // If the node has precedence edges (added when CastPP nodes are + // removed in final_graph_reshaping), fix the control of the + // node to cover the precedence edges and remove the + // dependencies. + Node* n = NULL; + for (uint i = node->len()-1; i >= node->req(); i--) { + Node* m = node->in(i); + if (m == NULL) continue; + // Skip the precedence edge if the test that guarded a CastPP: + // - was optimized out during escape analysis + // (OptimizePtrCompare): the CastPP's control isn't an end of + // block. + // - is moved in the branch of a dominating If: the control of + // the CastPP is then a Region. + if (m->is_block_proj() || m->is_block_start()) { + node->rm_prec(i); + if (n == NULL) { + n = m; + } else { + Block* bn = get_block_for_node(n); + Block* bm = get_block_for_node(m); + assert(is_dominator(bn, bm) || is_dominator(bm, bn), "one must dominate the other"); + n = is_dominator(bn, bm) ? m : n; + } + } + } + if (n != NULL) { + assert(node->in(0), "control should have been set"); + Block* bn = get_block_for_node(n); + Block* bnode = get_block_for_node(node->in(0)); + assert(is_dominator(bn, bnode) || is_dominator(bnode, bn), "one must dominate the other"); + if (!is_dominator(bn, bnode)) { + node->set_req(0, n); + } + } // process all inputs that are non NULL for (int i = node->req() - 1; i >= 0; --i) {