illegally shared subreg

[Stan Shebs]

Geoff Keating wrote:

>>Date: Fri, 11 Oct 2002 10:31:40 -0400 (EDT)
>>From: "Kaveh R. Ghazi" <ghazi@caip.rutgers.edu>
>>
>
>>Geoff/Stuart,
>>
>>This patch:
>>
>> > 2002-10-10  Stuart Hastings  <stuart@apple.com>
>> >  > 	* cse.c (struct cse_reg_info): Add subreg_ticked.
>> > 	(SUBREG_TICKED): New.
>> > 	(get_cse_reg_info): Initialize SUBREG_TICKED.
>> > 	(mention_regs): Use it.
>> > 	(invalidate): Set SUBREG_TICKED.
>> > 	(invalidate_for_call): Likewise.
>> > 	(addr_affects_sp_p): Likewise.
>>
>>can't be right.  It causes these new warnings:
>>
>> > cse.c:1226: warning: comparison between pointer and integer
>> > cse.c:1233: warning: assignment makes integer from pointer without a cast
>>
>>because you've got an int on one side and an rtx on the other.
>>(Irix6-cc gets a hard error on these lines instead of a warning.)
>>
>
>*sigh*.  The code would have worked in nearly all circumstances, since
>REGs are usually shared.  I will commit a patch (following Graham's
>suggestion) to fix the problem shortly.
>
>
>>PS: I wish the regression checker would notice warning regressions to
>>catch things like this.  I.e. things that don't cause a bootstrap or
>>testsuite failure, but which are clearly bugs.  We've discussed
>>strategies for implementing this without too much trouble in the past,
>>I hope this example will encourage you to see that it's worthwhile. :-)
>>
>
>Yes.  I'd really rather notice this sort of thing before it gets to
>the regression tester, though, ideally with a build failure; there are
>no circumstances under which 'assignment makes integer from pointer'
>is an OK warning while bootstrapping GCC, and notice that both Stuart
>and I both bootstrapped with this patch and didn't notice the warning.
>
Thus the oft-expressed wish to have -Werror in the 2nd and 3rd stages...

How close are we anyway?  Warnings in the mainline bootstrap seem
to be few and far between these days, in fact I can't remember the
last time I saw one.

Stan

>