From 0543df2871fde151a848be40a94222e3870490a2 Mon Sep 17 00:00:00 2001
From: "E. Branlard" <1318316+ebranlard@users.noreply.github.com>
Date: Mon, 20 Sep 2021 19:00:52 -0600
Subject: [PATCH] Fix AD Driver unallocated variable error with GCC 11 (#834)

---
 modules/aerodyn/src/AeroDyn_Driver_Subs.f90 | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/modules/aerodyn/src/AeroDyn_Driver_Subs.f90 b/modules/aerodyn/src/AeroDyn_Driver_Subs.f90
index 7f6b2867f..9c67fdb7f 100644
--- a/modules/aerodyn/src/AeroDyn_Driver_Subs.f90
+++ b/modules/aerodyn/src/AeroDyn_Driver_Subs.f90
@@ -569,15 +569,17 @@ subroutine concatOutputHeaders(dvr, WriteOutputHdr, WriteOutputUnt, errStat, err
    errStat = ErrID_None
    errMsg  = ''
 
+
    if (.not.allocated(dvr%out%WriteOutputHdr)) then
       call move_alloc(WriteOutputHdr, dvr%out%WriteOutputHdr)
       call move_alloc(WriteOutputUnt, dvr%out%WriteOutputUnt)   
    else
+      nOld = size(dvr%out%WriteOutputHdr)
+      nAdd = size(WriteOutputHdr)
+
       call move_alloc(dvr%out%WriteOutputHdr, TmpHdr)
       call move_alloc(dvr%out%WriteOutputUnt, TmpUnt)   
 
-      nOld = size(dvr%out%WriteOutputHdr)
-      nAdd = size(WriteOutputHdr)
       allocate(dvr%out%WriteOutputHdr(nOld+nAdd))
       allocate(dvr%out%WriteOutputUnt(nOld+nAdd))
       dvr%out%WriteOutputHdr(1:nOld) = TmpHdr