diff --git a/ext/opcache/Optimizer/zend_inference.c b/ext/opcache/Optimizer/zend_inference.c
index a130a7fba0d..9f9925e181b 100644
--- a/ext/opcache/Optimizer/zend_inference.c
+++ b/ext/opcache/Optimizer/zend_inference.c
@@ -2019,7 +2019,10 @@ static void handle_type_narrowing(const zend_op_array *op_array, zend_ssa *ssa,
 {
 	if (1) {
 		/* Right now, this is always a bug */
-		zend_error(E_WARNING, "Narrowing occurred during type inference. Please file a bug report on bugs.php.net");
+		int def_op_num = ssa->vars[var].definition;
+		const zend_op *def_opline = def_op_num >= 0 ? &op_array->opcodes[def_op_num] : NULL;
+		const char *def_op_name = def_opline ? zend_get_opcode_name(def_opline->opcode) : "PHI";
+		zend_error(E_WARNING, "Narrowing occurred during type inference of %s. Please file a bug report on bugs.php.net", def_op_name);
 	} else {
 		/* if new_type set resets some bits from old_type set
 		 * We have completely recalculate types of some dependent SSA variables
@@ -2555,7 +2558,7 @@ static int zend_update_type_info(const zend_op_array *op_array,
 					tmp |= MAY_BE_RCN;
 				}
 			}
-			if ((t1 & MAY_BE_ANY) == MAY_BE_LONG) {
+			if ((t1 & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_LONG) {
 				if (!ssa_var_info[ssa_ops[i].op1_use].has_range ||
 				    (opline->opcode == ZEND_PRE_DEC &&
 				     (ssa_var_info[ssa_ops[i].op1_use].range.underflow ||
@@ -2617,7 +2620,7 @@ static int zend_update_type_info(const zend_op_array *op_array,
 			if (t1 & (MAY_BE_RC1|MAY_BE_RCN)) {
 				tmp |= MAY_BE_RC1;
 			}
-			if ((t1 & MAY_BE_ANY) == MAY_BE_LONG) {
+			if ((t1 & (MAY_BE_ANY|MAY_BE_UNDEF)) == MAY_BE_LONG) {
 				if (!ssa_var_info[ssa_ops[i].op1_use].has_range ||
 				     (opline->opcode == ZEND_PRE_DEC &&
 				      (ssa_var_info[ssa_ops[i].op1_use].range.underflow ||
diff --git a/ext/opcache/Optimizer/zend_optimizer.c b/ext/opcache/Optimizer/zend_optimizer.c
index d3f30392fb2..602627df7ed 100644
--- a/ext/opcache/Optimizer/zend_optimizer.c
+++ b/ext/opcache/Optimizer/zend_optimizer.c
@@ -1481,8 +1481,11 @@ int zend_optimize_script(zend_script *script, zend_long optimization_level, zend
 		for (i = 0; i < call_graph.op_arrays_count; i++) {
 			func_info = ZEND_FUNC_INFO(call_graph.op_arrays[i]);
 			if (func_info) {
-				zend_dfa_analyze_op_array(call_graph.op_arrays[i], &ctx, &func_info->ssa);
-				func_info->flags = func_info->ssa.cfg.flags;
+				if (zend_dfa_analyze_op_array(call_graph.op_arrays[i], &ctx, &func_info->ssa) == SUCCESS) {
+					func_info->flags = func_info->ssa.cfg.flags;
+				} else {
+					ZEND_SET_FUNC_INFO(call_graph.op_arrays[i], NULL);
+				}
 			}
 		}
 
diff --git a/ext/opcache/tests/bug77058.phpt b/ext/opcache/tests/bug77058.phpt
new file mode 100644
index 00000000000..6a5a83cef7a
--- /dev/null
+++ b/ext/opcache/tests/bug77058.phpt
@@ -0,0 +1,20 @@
+--TEST--
+Bug #77058: Type inference in opcache causes side effects
+--FILE--
+<?php 
+
+function myfunc(){
+  $Nr = 0;
+  while(1){
+    $x--;
+    $x++;
+    if( ++ $Nr >= 2 ) break;
+  }
+  echo "'$Nr' is expected to be 2", PHP_EOL;
+}
+myfunc();
+
+?>
+--EXPECTF--
+Notice: Undefined variable: x in %s on line %d
+'2' is expected to be 2