[Bug c/71602] [6/7 regression] ICE on __builtin_va_arg in build_va_arg, at c-family/c-common.c:5810

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71602

--- Comment #10 from vries at gcc dot gnu.org ---
Created attachment 39482
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39482&action=edit
alternate approach patch

Alternate approach patch, fixing the problem by making canonical_va_list_type
more strict, as suggested at
https://gcc.gnu.org/ml/gcc-patches/2016-06/msg01709.html .

Passes x86_64 m64/m32 bootstrap and reg-test.

Todo: cleanup patch, add changelog entry and submit