Re: Proposed patch for PR 7507 and PR 9289

[Dale Johannesen <dalej at apple dot com>]

On Friday, January 17, 2003, at 05:45  PM, Christian Ehrhardt wrote:

> On Fri, Jan 17, 2003 at 10:31:34AM -0800, Dale Johannesen wrote:
> > This is (at least) the 3rd bug like this that has shown up.  Might it
> > be a
> > good idea to rewrite the low-level label infrastructure to allow
> > duplicate labels in the placeholder alternatives?  That might be
> > stabler.
> Assume that we actually allow labels in a call placeholder.
> This would mean that we generate different CODE_LABEL insns for
> each alternative in the call placeholder because same insn can't
> be in different chains. As long as the only jumps to the label are
> from within the same call placeholder this is fine but there may
> well be jumps from outside the call placeholder. These jumps would
> have a hard time to figure out what the label number is that they
> should jump to....
I had in mind multiple labels with the same number (but different 
insns),
in different placeholders.  Exactly one of them would survive after the
placeholders are resolved.  If you can construct a case where one 
placeholder
contains a label jumped to from outside and another doesn't, that would 
break.
That's not possible, because choosing the placeholder without the label 
would
result in invalid RTL.

This was just an idea thrown out, I didn't intend it to block approval 
of your
patch.  I have no authority, but the patch looks correct to me.