From d2c9db3f1f904c6dba0ed00892d4ac47164a3e0a Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Sat, 11 May 2019 18:33:12 +1000
Subject: [PATCH] AP_FlashStorage: fixed build error with -O0

---
 libraries/AP_FlashStorage/AP_FlashStorage.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_FlashStorage/AP_FlashStorage.cpp b/libraries/AP_FlashStorage/AP_FlashStorage.cpp
index 77c89ab145..1754a349bf 100644
--- a/libraries/AP_FlashStorage/AP_FlashStorage.cpp
+++ b/libraries/AP_FlashStorage/AP_FlashStorage.cpp
@@ -315,7 +315,9 @@ bool AP_FlashStorage::write_all()
     debug("write_all to sector %u at %u with reserved_space=%u\n",
            current_sector, write_offset, reserved_space);
     for (uint16_t ofs=0; ofs<storage_size; ofs += max_write) {
-        uint8_t n = MIN(max_write, storage_size-ofs);
+        // local variable needed to overcome problem with MIN() macro and -O0
+        const uint8_t max_write_local = max_write;
+        uint8_t n = MIN(max_write_local, storage_size-ofs);
         if (!all_zero(ofs, n)) {
             if (!write(ofs, n)) {
                 return false;