Replace ZEND_DEREF with ZEND_QM_ASSIGN

The op1=IS_VAR spec was pretty much identical, and there are most likely already
better optimizations for QM_ASSIGN in place.

Author: iluuu1994

Zend/Optimizer/dce.c

@@ -125,7 +125,6 @@ static inline bool may_have_side_effects(
 		case ZEND_FUNC_GET_ARGS:
 		case ZEND_ARRAY_KEY_EXISTS:
 		case ZEND_COPY_TMP:
-		case ZEND_DEREF:
 			/* No side effects */
 			return false;
 		case ZEND_FREE:

Zend/Optimizer/zend_inference.c

@@ -5033,7 +5033,6 @@ ZEND_API bool zend_may_throw_ex(const zend_op *opline, const zend_ssa_op *ssa_op
 		case ZEND_COPY_TMP:
 		case ZEND_JMP_NULL:
 		case ZEND_JMP_FRAMELESS:
-		case ZEND_DEREF:
 			return 0;
 		case ZEND_IS_IDENTICAL:
 		case ZEND_IS_NOT_IDENTICAL:

Zend/zend_compile.c

@@ -3407,7 +3407,8 @@ static void zend_compile_list_assign(
 
 	if (result) {
 		if ((type == BP_VAR_R || type == BP_VAR_IS) && expr_node->op_type == IS_VAR) {
-			zend_emit_op_tmp(result, ZEND_DEREF, expr_node, NULL);
+			/* Deref. */
+			zend_emit_op_tmp(result, ZEND_QM_ASSIGN, expr_node, NULL);
 		} else {
 			*result = *expr_node;
 		}
@@ -3650,8 +3651,9 @@ static void zend_compile_assign_ref(znode *result, zend_ast *ast, uint32_t type)
 	}
 
 	if (result && (type == BP_VAR_R || type == BP_VAR_IS)) {
+		/* Deref. */
 		znode tmp_result = *result;
-		zend_emit_op_tmp(result, ZEND_DEREF, &tmp_result, NULL);
+		zend_emit_op_tmp(result, ZEND_QM_ASSIGN, &tmp_result, NULL);
 	}
 }
 /* }}} */
@@ -10729,7 +10731,7 @@ static void zend_compile_conditional(znode *result, zend_ast *ast) /* {{{ */
 
 	zend_compile_expr(&false_node, false_ast);
 
-	opline_qm_assign2 = zend_emit_op(NULL, ZEND_QM_ASSIGN, &false_node, NULL);
+	opline_qm_assign2 = zend_emit_op_tmp(NULL, ZEND_QM_ASSIGN, &false_node, NULL);
 	SET_NODE(opline_qm_assign2->result, result);
 
 	zend_update_jump_target_to_next(opnum_jmp);

Zend/zend_vm_def.h

@@ -10006,27 +10006,6 @@ ZEND_VM_HANDLER(209, ZEND_INIT_PARENT_PROPERTY_HOOK_CALL, CONST, UNUSED|NUM, NUM
 	ZEND_VM_NEXT_OPCODE();
 }
 
-ZEND_VM_HANDLER(211, ZEND_DEREF, VAR, UNUSED)
-{
-	USE_OPLINE
-
-	zval *value = GET_OP1_ZVAL_PTR(BP_VAR_R);
-
-	if (Z_TYPE_P(value) == IS_REFERENCE) {
-		zend_reference *ref = Z_REF_P(value);
-		ZVAL_COPY_VALUE(EX_VAR(opline->result.var), &ref->val);
-		if (GC_DELREF(ref) == 0) {
-			efree_size(ref, sizeof(zend_reference));
-		} else {
-			Z_TRY_ADDREF_P(EX_VAR(opline->result.var));
-		}
-	} else {
-		ZVAL_COPY_VALUE(EX_VAR(opline->result.var), value);
-	}
-
-	ZEND_VM_NEXT_OPCODE();
-}
-
 ZEND_VM_HOT_TYPE_SPEC_HANDLER(ZEND_JMP, (OP_JMP_ADDR(op, op->op1) > op), ZEND_JMP_FORWARD, JMP_ADDR, ANY)
 {
 	USE_OPLINE