diff --git a/Zend/Optimizer/zend_ssa.c b/Zend/Optimizer/zend_ssa.c
index 67165a9b26d..84f0d4d260f 100644
--- a/Zend/Optimizer/zend_ssa.c
+++ b/Zend/Optimizer/zend_ssa.c
@@ -17,12 +17,13 @@
    +----------------------------------------------------------------------+
 */
 
-#include "zend_compile.h"
-#include "zend_dfg.h"
 #include "zend_ssa.h"
+#include "zend_arena.h"
+#include "zend_optimizer_internal.h"
+#include "zend_dfg.h"
 #include "zend_dump.h"
-#include "zend_inference.h"
-#include "Optimizer/zend_optimizer_internal.h"
+#include "zend_inference.h" // for zend_sub_will_overflow()
+#include "zend_type_info.h" // for MAY_BE_REF
 
 static bool dominates(const zend_basic_block *blocks, int a, int b) {
 	while (blocks[b].level > blocks[a].level) {
diff --git a/Zend/Optimizer/zend_ssa.h b/Zend/Optimizer/zend_ssa.h
index 9fde352c79c..035cce5cae2 100644
--- a/Zend/Optimizer/zend_ssa.h
+++ b/Zend/Optimizer/zend_ssa.h
@@ -19,8 +19,14 @@
 #ifndef ZEND_SSA_H
 #define ZEND_SSA_H
 
-#include "zend_optimizer.h"
 #include "zend_cfg.h"
+#include "zend_compile.h" // for struct _zend_op
+#include "zend_long.h"
+#include "zend_portability.h" // for BEGIN_EXTERN_C
+#include "zend_types.h" // for zend_result
+
+typedef struct _zend_class_entry zend_class_entry;
+typedef struct _zend_script zend_script;
 
 typedef struct _zend_ssa_range {
 	zend_long              min;