https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70948
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
The following should fix it, I am going to test it on x86_64:
Index: gcc/tree-ssa-structalias.c
===================================================================
--- gcc/tree-ssa-structalias.c (revision 235945)
+++ gcc/tree-ssa-structalias.c (working copy)
@@ -4492,7 +4492,7 @@ find_func_aliases_for_builtin_call (stru
tree valist = gimple_call_arg (t, 0);
struct constraint_expr rhs, *lhsp;
unsigned i;
- get_constraint_for (valist, &lhsc);
+ get_constraint_for_ptr_offset (valist, NULL_TREE, &lhsc);
do_deref (&lhsc);
/* The va_list gets access to pointers in variadic
arguments. Which we know in the case of IPA analysis
