Patch: default to -mieee on alpha

[Jeff Sturm]

On 11 Feb 2003, Tom Tromey wrote:
> I'm curious about something, though.  How does this interact with
> strict or non-strict fp?

No idea.

> Does -mieee have a negative performance impact?

Yes, it places trap barriers in the instruction stream for fp operations.

> If so, is -mno-ieee something we could or would want to
> support for non-strictfp code?

Possibly.  The difficulty is that fp traps become unrecoverable.  For
example, this class will terminate on SIGFPE without -mieee:

public class PD {
  public static void main(String[] args) {
    double x = Double.NaN;
    System.out.println(x == x);
  }
}

Even x86 with -ffast-math doesn't fault on this code (though it returns
the wrong answer).

BTW is this example OK for the testsuite?  In libjava.lang?

Jeff