On Tue, Mar 6, 2012 at 12:51 AM, Richard Kenner
>> I found a weird piece of code that was added by kenner in a really early
>> revision. It checks for VAR_DECLs with frame or stack pointers as
>> DECL_RTL, and the comment in front of it mentions strength reduction.
>> Presumably this was for the old loop optimizer? I can't think of
>> anything that would require this in a modern version of gcc.
> I think such a VAR_DECL would occur in cases of alloca. I don't understand
> the comment about strength reduction (despite obviously having written it!)
> because the old loop optimizer ran on RTL and this is talking about trees.
> My guess is that this isn't dead.
I don't see how a VAR_DECL can ever get a DECL_RTL equal to one of
the mentioned regs.
The patch is ok if a gcc_unreachable () inside the if () passes bootstrap.