Fix T81226: Crash opening 64bit files with endian switching

Endian switching when loading 64bit blend files on a 64bit system was
crashing as the endian switching is only applicable when loading
on 32 bit systems.

This crash goes back to 2.7x, it looks like this never worked
all the way back to the first commit.

1 files changed, 6 insertions, 2 deletions

diff --git a/source/blender/makesdna/intern/dna_genfile.c b/source/blender/makesdna/intern/dna_genfile.c
index 511f9f354c9..d7360c67210 100644
--- a/source/blender/makesdna/intern/dna_genfile.c
+++ b/source/blender/makesdna/intern/dna_genfile.c
@@ -1030,8 +1030,12 @@ void DNA_struct_switch_endian(const SDNA *oldsdna, int oldSDNAnr, char *data)
     else {
       /* non-struct field type */
       if (ispointer(name)) {
-        if (oldsdna->pointer_size == 8) {
-          BLI_endian_switch_int64_array((int64_t *)cur, old_name_array_len);
+        /* See readfile.c (#bh4_from_bh8 swap endian argument),
+         * this is only done when reducing the size of a pointer from 4 to 8. */
+        if (sizeof(void *) < 8) {
+          if (oldsdna->pointer_size == 8) {
+            BLI_endian_switch_int64_array((int64_t *)cur, old_name_array_len);
+          }
         }
       }
       else {