[Bug rtl-optimization/116037] [15 Regression] wrong code at -O2 with vector masking and add

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116037

--- Comment #3 from Jeffrey A. Law <law at gcc dot gnu.org> ---
So this is fixed by a patch I'm still working on.  Essentially I want to stop
relying on an empty LIVE_TMP to denote that we skipped a destination's set. 
That's not quite ready yet, but I think it's damn close.