[llvm] r255175 - [X86] Enable shrink-wrapping by default, but keep it disabled for stack frames

[Joerg Sonnenberger via llvm-commits]

On Wed, Dec 09, 2015 at 11:08:19PM -0000, Quentin Colombet via llvm-commits wrote:
> Author: qcolombet
> Date: Wed Dec  9 17:08:18 2015
> New Revision: 255175
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=255175&view=rev
> Log:
> [X86] Enable shrink-wrapping by default, but keep it disabled for stack frames
> without a frame pointer when unwind may happen.
> This is a workaround for a bug in the way we emit the CFI directives for
> frameless unwind information. See PR25614.

This hangs when compiling the attached input with -O2.

Joerg
-------------- next part --------------
a, b, c;
void fn1() {
  if (c)
    return;
  fn2();
}

fn3() {
  if (a)
    b = 0;
  do {
    fn1();
    fn4();
  } while (!c);
}