[Bug inline-asm/94180] New: inconsistent operand constraints: "+X"

[frederic.recoules@univ-grenoble-alpes.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94180

            Bug ID: 94180
           Summary: inconsistent operand constraints: "+X"
           Product: gcc
           Version: 9.2.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: inline-asm
          Assignee: unassigned at gcc dot gnu.org
          Reporter: frederic.recoules@univ-grenoble-alpes.fr
  Target Milestone: ---

Consider the following code snippet:

int main (int argc, char *argv[])
{
    int k = 0;
    asm ("" : "+X" (k));
    return k;
}

It produces the following error:

<source>: In function 'main':

<source>:17:5: error: inconsistent operand constraints in an 'asm'

   17 |     asm ("" : "+X" (k));

      |     ^~~