The fix to PR33552 unfortunately breaks the Linux kernel build. Reduced testcase attached, but hey, I'll put it inline as well:
int f(int n) { int x; asm("" : "=&c"(n), "=r"(x) : "1"(n), "0"(n)); return n; } And the error is: usercopy.i:5: error: 'asm' operand has impossible constraints -- Summary: Breakage caused by the fix to PR33552 Product: gcc Version: 4.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: inline-asm AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: segher at kernel dot crashing dot org GCC target triplet: i386-linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33600