diff --git a/src/libsodium/crypto_pwhash/argon2/argon2-core.c b/src/libsodium/crypto_pwhash/argon2/argon2-core.c
index c69ed710..b52b04d3 100644
--- a/src/libsodium/crypto_pwhash/argon2/argon2-core.c
+++ b/src/libsodium/crypto_pwhash/argon2/argon2-core.c
@@ -217,78 +217,6 @@ finalize(const argon2_context *context, argon2_instance_t *instance)
     }
 }
 
-uint32_t
-index_alpha(const argon2_instance_t *instance,
-            const argon2_position_t *position, uint32_t pseudo_rand,
-            int same_lane)
-{
-    /*
-     * Pass 0:
-     *      This lane : all already finished segments plus already constructed
-     * blocks in this segment
-     *      Other lanes : all already finished segments
-     * Pass 1+:
-     *      This lane : (SYNC_POINTS - 1) last segments plus already constructed
-     * blocks in this segment
-     *      Other lanes : (SYNC_POINTS - 1) last segments
-     */
-    uint32_t reference_area_size;
-    uint64_t relative_position;
-    uint32_t start_position, absolute_position;
-
-    if (position->pass == 0) {
-        /* First pass */
-        if (position->slice == 0) {
-            /* First slice */
-            reference_area_size =
-                position->index - 1; /* all but the previous */
-        } else {
-            if (same_lane) {
-                /* The same lane => add current segment */
-                reference_area_size =
-                    position->slice * instance->segment_length +
-                    position->index - 1;
-            } else {
-                reference_area_size =
-                    position->slice * instance->segment_length +
-                    ((position->index == 0) ? (-1) : 0);
-            }
-        }
-    } else {
-        /* Second pass */
-        if (same_lane) {
-            reference_area_size = instance->lane_length -
-                                  instance->segment_length + position->index -
-                                  1;
-        } else {
-            reference_area_size = instance->lane_length -
-                                  instance->segment_length +
-                                  ((position->index == 0) ? (-1) : 0);
-        }
-    }
-
-    /* 1.2.4. Mapping pseudo_rand to 0..<reference_area_size-1> and produce
-     * relative position */
-    relative_position = pseudo_rand;
-    relative_position = relative_position * relative_position >> 32;
-    relative_position = reference_area_size - 1 -
-                        (reference_area_size * relative_position >> 32);
-
-    /* 1.2.5 Computing starting position */
-    start_position = 0;
-
-    if (position->pass != 0) {
-        start_position = (position->slice == ARGON2_SYNC_POINTS - 1)
-                             ? 0
-                             : (position->slice + 1) * instance->segment_length;
-    }
-
-    /* 1.2.6. Computing absolute position */
-    absolute_position = (start_position + relative_position) %
-                        instance->lane_length; /* absolute position */
-    return absolute_position;
-}
-
 void
 fill_memory_blocks(argon2_instance_t *instance, uint32_t pass)
 {
diff --git a/src/libsodium/crypto_pwhash/argon2/argon2-core.h b/src/libsodium/crypto_pwhash/argon2/argon2-core.h
index 0c07bc2b..caab1038 100644
--- a/src/libsodium/crypto_pwhash/argon2/argon2-core.h
+++ b/src/libsodium/crypto_pwhash/argon2/argon2-core.h
@@ -136,9 +136,76 @@ typedef struct Argon2_thread_data {
  * If so we can reference the current segment
  * @pre All pointers must be valid
  */
-uint32_t index_alpha(const argon2_instance_t *instance,
-                     const argon2_position_t *position, uint32_t pseudo_rand,
-                     int same_lane);
+static uint32_t index_alpha(const argon2_instance_t *instance,
+                            const argon2_position_t *position, uint32_t pseudo_rand,
+                            int same_lane)
+{
+    /*
+     * Pass 0:
+     *      This lane : all already finished segments plus already constructed
+     * blocks in this segment
+     *      Other lanes : all already finished segments
+     * Pass 1+:
+     *      This lane : (SYNC_POINTS - 1) last segments plus already constructed
+     * blocks in this segment
+     *      Other lanes : (SYNC_POINTS - 1) last segments
+     */
+    uint32_t reference_area_size;
+    uint64_t relative_position;
+    uint32_t start_position, absolute_position;
+
+    if (position->pass == 0) {
+        /* First pass */
+        if (position->slice == 0) {
+            /* First slice */
+            reference_area_size =
+                position->index - 1; /* all but the previous */
+        } else {
+            if (same_lane) {
+                /* The same lane => add current segment */
+                reference_area_size =
+                    position->slice * instance->segment_length +
+                    position->index - 1;
+            } else {
+                reference_area_size =
+                    position->slice * instance->segment_length +
+                    ((position->index == 0) ? (-1) : 0);
+            }
+        }
+    } else {
+        /* Second pass */
+        if (same_lane) {
+            reference_area_size = instance->lane_length -
+                                  instance->segment_length + position->index -
+                                  1;
+        } else {
+            reference_area_size = instance->lane_length -
+                                  instance->segment_length +
+                                  ((position->index == 0) ? (-1) : 0);
+        }
+    }
+
+    /* 1.2.4. Mapping pseudo_rand to 0..<reference_area_size-1> and produce
+     * relative position */
+    relative_position = pseudo_rand;
+    relative_position = relative_position * relative_position >> 32;
+    relative_position = reference_area_size - 1 -
+                        (reference_area_size * relative_position >> 32);
+
+    /* 1.2.5 Computing starting position */
+    start_position = 0;
+
+    if (position->pass != 0) {
+        start_position = (position->slice == ARGON2_SYNC_POINTS - 1)
+                             ? 0
+                             : (position->slice + 1) * instance->segment_length;
+    }
+
+    /* 1.2.6. Computing absolute position */
+    absolute_position = (start_position + relative_position) %
+                        instance->lane_length; /* absolute position */
+    return absolute_position;
+}
 
 /*
  * Function that validates all inputs against predefined restrictions and return