[Bug inline-asm/39590] New: inline asm %z on amd64 says "ll" instead of "q"

felix-gcc at fefe dot de gcc-bugzilla@gcc.gnu.org
Mon Mar 30 18:17:00 GMT 2009


I am trying to write an inline asm statement that atomically adds a number to a
memory variable.  Here's what I came up with:

#define atomic_add(mem,val) asm volatile ("lock; add%z0 %1, %0": "+m" (mem):
"ir" (val))

This appears to work fine on x86, but in 64-bit mode %z returns "ll" instead of
"q" for 64-bit values like size_t, and thus the assembler complains like this:

t.c:53: Error: no such instruction: `addll $3,x.5802(%rip)'

If I understand %z correctly, this is exactly what it is meant for... right?
Please make it return "q" in this case.


-- 
           Summary: inline asm %z on amd64 says "ll" instead of "q"
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: inline-asm
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: felix-gcc at fefe dot de
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39590



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