[Bug tree-optimization/116647] [15 Regression] Internal compiler error in operator[], at vec.h:910

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116647

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
So first of all we classify something as double reduction that isn't.  Adding a
check to that fixes the issue.