The x=x "initialization" idea by paulkon...@comcast.net failed to turn off the warning for me.
Joe Buck may be right that gcc "already does the right thing" but actually I was dealing with not a 64-bit wide, but actually a 128-bit-wide type, which might later become 256-wide or even 512; and to load it with 0s actually needs a lot of loading of constants from the instruction stream. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)