Eliminate more VERIFY_RETURN_TYPE instructions

Author: dstogov

Zend/Optimizer/dfa_pass.c

@@ -1293,30 +1293,52 @@ void zend_dfa_optimize_op_array(zend_op_array *op_array, zend_optimizer_ctx *ctx
 				} else if (opline->opcode == ZEND_VERIFY_RETURN_TYPE
 				 && opline->op1_type != IS_CONST
 				 && ssa->ops[op_1].op1_def == v
-				 && ssa->ops[op_1].op1_use >= 0
-				 && ssa->ops[op_1].op1_use_chain == -1
-				 && can_elide_return_type_check(ctx->script, op_array, ssa, &ssa->ops[op_1])) {
+				 && ssa->ops[op_1].op1_use >= 0) {
+					int orig_var = ssa->ops[op_1].op1_use;
+					int ret = ssa->vars[v].use_chain;
+
+					if (ssa->ops[op_1].op1_use_chain == -1
+					 && can_elide_return_type_check(ctx->script, op_array, ssa, &ssa->ops[op_1])) {
 
 // op_1: VERIFY_RETURN_TYPE #orig_var.? [T] -> #v.? [T] => NOP
 
-					int orig_var = ssa->ops[op_1].op1_use;
-					zend_ssa_unlink_use_chain(ssa, op_1, orig_var);
+						zend_ssa_unlink_use_chain(ssa, op_1, orig_var);
+
+						if (ret >= 0) {
+							ssa->ops[ret].op1_use = orig_var;
+							ssa->ops[ret].op1_use_chain = ssa->vars[orig_var].use_chain;
+							ssa->vars[orig_var].use_chain = ret;
+						}
+
+						ssa->vars[v].definition = -1;
+						ssa->vars[v].use_chain = -1;
+
+						ssa->ops[op_1].op1_def = -1;
+						ssa->ops[op_1].op1_use = -1;
+
+						MAKE_NOP(opline);
+						remove_nops = 1;
+					} else if (ret >= 0
+					 && ssa->ops[ret].op1_use == v
+					 && ssa->ops[ret].op1_use_chain == -1
+					 && can_elide_return_type_check(ctx->script, op_array, ssa, &ssa->ops[op_1])) {
+
+// op_1: VERIFY_RETURN_TYPE #orig_var.? [T] -> #v.? [T] => NOP
+
+						zend_ssa_replace_use_chain(ssa, op_1, ret, orig_var);
 
-					int ret = ssa->vars[v].use_chain;
-					if (ret >= 0) {
 						ssa->ops[ret].op1_use = orig_var;
-						ssa->ops[ret].op1_use_chain = ssa->vars[orig_var].use_chain;
-						ssa->vars[orig_var].use_chain = ret;
-					}
+						ssa->ops[ret].op1_use_chain = ssa->ops[op_1].op1_use_chain;
 
-					ssa->vars[v].definition = -1;
-					ssa->vars[v].use_chain = -1;
+						ssa->vars[v].definition = -1;
+						ssa->vars[v].use_chain = -1;
 
-					ssa->ops[op_1].op1_def = -1;
-					ssa->ops[op_1].op1_use = -1;
+						ssa->ops[op_1].op1_def = -1;
+						ssa->ops[op_1].op1_use = -1;
 
-					MAKE_NOP(opline);
-					remove_nops = 1;
+						MAKE_NOP(opline);
+						remove_nops = 1;
+					}
 				}
 			}
 

Zend/Optimizer/zend_ssa.c

@@ -1209,6 +1209,46 @@ void zend_ssa_unlink_use_chain(zend_ssa *ssa, int op, int var) /* {{{ */
 }
 /* }}} */
 
+void zend_ssa_replace_use_chain(zend_ssa *ssa, int op, int new_op, int var) /* {{{ */
+{
+	if (ssa->vars[var].use_chain == op) {
+		ssa->vars[var].use_chain = new_op;
+		return;
+	} else {
+		int use = ssa->vars[var].use_chain;
+
+		while (use >= 0) {
+			if (ssa->ops[use].result_use == var) {
+				if (ssa->ops[use].res_use_chain == op) {
+					ssa->ops[use].res_use_chain = new_op;
+					return;
+				} else {
+					use = ssa->ops[use].res_use_chain;
+				}
+			} else if (ssa->ops[use].op1_use == var) {
+				if (ssa->ops[use].op1_use_chain == op) {
+					ssa->ops[use].op1_use_chain = new_op;
+					return;
+				} else {
+					use = ssa->ops[use].op1_use_chain;
+				}
+			} else if (ssa->ops[use].op2_use == var) {
+				if (ssa->ops[use].op2_use_chain == op) {
+					ssa->ops[use].op2_use_chain = new_op;
+					return;
+				} else {
+					use = ssa->ops[use].op2_use_chain;
+				}
+			} else {
+				break;
+			}
+		}
+	}
+	/* something wrong */
+	ZEND_UNREACHABLE();
+}
+/* }}} */
+
 void zend_ssa_remove_instr(zend_ssa *ssa, zend_op *opline, zend_ssa_op *ssa_op) /* {{{ */
 {
 	if (ssa_op->result_use >= 0) {

Zend/Optimizer/zend_ssa.h

@@ -149,6 +149,7 @@ ZEND_API zend_result zend_build_ssa(zend_arena **arena, const zend_script *scrip
 ZEND_API void zend_ssa_compute_use_def_chains(zend_arena **arena, const zend_op_array *op_array, zend_ssa *ssa);
 ZEND_API int zend_ssa_rename_op(const zend_op_array *op_array, const zend_op *opline, uint32_t k, uint32_t build_flags, int ssa_vars_count, zend_ssa_op *ssa_ops, int *var);
 void zend_ssa_unlink_use_chain(zend_ssa *ssa, int op, int var);
+void zend_ssa_replace_use_chain(zend_ssa *ssa, int op, int new_op, int var);
 
 void zend_ssa_remove_predecessor(zend_ssa *ssa, int from, int to);
 void zend_ssa_remove_defs_of_instr(zend_ssa *ssa, zend_ssa_op *ssa_op);