Re: [PATCH] Segfault in rtx_varies_p

[Mark Mitchell <mark at codesourcery dot com>]

Paul Brook wrote:

> > > (insn (set (reg 103) (mem (plus (reg 101) (reg 102))))
> > > 	(expr_list:REG_EQUAL (plus (reg 101) (symbol_ref "bar")))
> > > 	(nil))
> > >      
> > This last REG_EQUAL note doesn't look right to me.
> >
> > It references "bar", rather than "digs".  Why is that?
> >    
>
> A typo, it should be "digs".
>  
Oh!

You should check that rtx_varies_p still returns true for the larger 
expression containing the NULL rtx; the (use mem:blk scratch) should 
cause us to believe that the entire expression is variable.

In that case, I think your patch is fine for mainline and csl-arm-branch.

For 3.4, we should show that it really is a regression.  We're taking a 
risk that we're somehow changing an ICE into wrong-code, and that would 
be worse.

Thanks,

--
Mark Mitchell
CodeSourcery, LLC
(916) 791-8304
mark@codesourcery.com