https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97259
H.J. Lu <hjl.tools at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |INVALID Status|UNCONFIRMED |RESOLVED --- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> --- Never mind. The register operand is a memory-mapped I/O address.