[Bug libfortran/79956] [7 Regression] many new -Wmaybe-uninitialized warnings with bootstrap-O3

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79956

--- Comment #20 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
The following fixes the warning for me:

diff --git a/libgfortran/m4/reshape.m4 b/libgfortran/m4/reshape.m4
index 787844ec42d..42379d58a29 100644
--- a/libgfortran/m4/reshape.m4
+++ b/libgfortran/m4/reshape.m4
@@ -236,6 +236,10 @@ reshape_'rtype_ccode` ('rtype` * const restrict ret,
     }

   sdim = GFC_DESCRIPTOR_RANK (source);
+
+  if (!sdim)
+    return;
+
   ssize = 1;
   sempty = 0;
   for (n = 0; n < sdim; n++)