[llvm] r209638 - [PPC] Use alias symbols in address computation.

[Rafael Espíndola]

> I don't have one. If you could try a bootstrap, that would be great.

The difference is from cases like


define void @foo()  {
  ret void
}
declare i32 @bar(i8*)
define  void @zed() {
  call i32 @bar(i8* bitcast (void ()* @foo to i8*))
  ret void
}


trunk produces
        addis 3, 2, .LC1 at toc@ha
        ld 3, .LC1 at toc@l(3)

and the patch produces

        addis 3, 2, .LC1 at toc@ha
        addi 3, 3, .LC1 at toc@l

So it looks like it decides to use a constant pool and then passes the
address of the pool. If instead of a function we have a variable, both
trunk and patch work by doing

        addis 3, 2, var at toc@ha
        addi 3, 3, var at toc@l

that is, they don't create the constant pool entry.

It is easy to fix the patch to do a load for functions, but I wonder
why it is considered better/necessary to create a constant pull for
them. Couldn't we use

        addis 3, 2, func at toc@ha
        addi 3, 3, func at toc@l

Cheers,
Rafael