I noticed a lot of warning when building Gambit-REPL in clang, so I decided to see whether they could be triggered in gcc.
So I configured gambit with
./configure 'CC=/pkgs/gcc-devel/bin/gcc -W -Wall -march=native -Wconversion' '--enable-single-host' '--enable-multiple-versions'
and indeed, the -Wconversion did pop up a lot of warnings; the log is attached.
I'm a bit concerned when we have individual vector sizes > 2GB, etc. (My home machine now comes with 32GB RAM; at work, there's a server with 160GB.)
Brad