On Oct 12, 2015, at 3:32 PM, Chen Gang <xili_gchen_5...@hotmail.com> wrote:
>
> OK, thanks. If we really need to fix it, which target hook should I use?
> (or do we need a new target hook?)
So, the first discussion would be if it is, or is not a bug. If it isn’t, then
there is no fix. No fix, no target hook. So far, Bernd said not a bug.
So, I’ll note that one _can_ do this with the stack pointer, as a fixed
register.
When the frame pointer is fixed, one cannot do this.
The code that does this is:
/* Diagnose uses of the hard frame pointer when it is used as a global
register. Often we can get away with letting the user appropriate
the frame pointer, but we should let them know when code generation
makes that impossible. */
if (global_regs[HARD_FRAME_POINTER_REGNUM] && frame_pointer_needed)
{
tree decl = global_regs_decl[HARD_FRAME_POINTER_REGNUM];
error_at (DECL_SOURCE_LOCATION (current_function_decl),
"frame pointer required, but reserved");
inform (DECL_SOURCE_LOCATION (decl), "for %qD", decl);
}
to `fix it’, one would simple remove this chunk as misguided and fix up any
code gen issues exposed.
