1 files changed, 8 insertions, 0 deletions
diff --git a/gcc/lto/lto-symtab.c b/gcc/lto/lto-symtab.c
index ce9e146..5ab9977 100644
--- a/gcc/lto/lto-symtab.c
+++ b/gcc/lto/lto-symtab.c
@@ -655,6 +655,14 @@ lto_symtab_merge_decls_2 (symtab_node *first, bool diagnosed_p)
   /* Diagnose all mismatched re-declarations.  */
   FOR_EACH_VEC_ELT (mismatches, i, decl)
     {
+      /* Do not diagnose two built-in declarations, there is no useful
+         location in that case.  It also happens for AVR if two built-ins
+         use the same asm name because their libgcc assembler code is the
+         same, see PR78562.  */
+      if (DECL_IS_BUILTIN (prevailing->decl)
+	  && DECL_IS_BUILTIN (decl))
+	continue;
+
       int level = warn_type_compatibility_p (TREE_TYPE (prevailing->decl),
 					     TREE_TYPE (decl),
 					     DECL_COMDAT (decl));