This is reported by Coverity. The algorithm description at
ftp://ftp.icm.edu.pl/packages/ggi/doc/hw/sparc/Sparc.pdf suggests
that the 32-bit parts of rs2, after the left shift, is treated
as a 64-bit integer. Bits 32 and above are used to do the
saturating truncation.
Backports commit 12a3567c4099be194b44987ac5d7d65b99bcfab7 from qemu