If such a mechanism existed, asm programs would able to be structured to honor their declaration as such; thereby enable implementations of set/longjump to exclude them from being otherwise improperly save/restored, for example, etc.
-- Summary: GCC needs mechanism to expose compile-time declared reserved global registers to asm programs. Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: schlie at comcast dot net CC: gcc-bugs at gcc dot gnu dot org GCC build triplet: *-*-* GCC host triplet: *-*-* GCC target triplet: *-*-* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19795