[Bug rtl-optimization/19599] New: function pointer prevents tail-call optimisation

[pb at gcc dot gnu dot org]

This code:

int g(int);

int f(int x)
{
  return g(x);
}

is correctly compiled to just

f:
      b    g


But, if g is a function pointer:

int (*g)(int);

int f(int x)
{
  return g(x);
}

then the generated code becomes much less efficient:

f:
        str     lr, [sp, #-4]!
        ldr     r3, .L3
        mov     lr, pc
        ldr     pc, [r3, #0]
        ldr     pc, [sp], #4

-- 
           Summary: function pointer prevents tail-call optimisation
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pb at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: arm-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19599