Re: [PATCH] loop-iv: Fix up bounds computation

[Jeff Law <jeffreyalaw@gmail.com>]

On 4/13/23 07:45, Jakub Jelinek wrote:
> On Thu, Apr 13, 2023 at 06:35:07AM -0600, Jeff Law wrote:
>> Bootstrap was successful with v3, but there's hundreds of testsuite failures
>> due to the simplify-rtx hunk.  compile/20070520-1.c for example when
>> compiled with:  -O3 -funroll-loops -march=rv64gc -mabi=lp64d
>>
>> Thursdays are my hell day.  It's unlikely I'd be able to look at this at all
>> today.
> 
> So, seems to me this is because loop-iv.cc asks for invalid RTL to be
> simplified, it calls simplify_gen_binary (AND, SImode,
> (subreg:SI (plus:DI (reg:DI 289 [ ivtmp_312 ])
>          (const_int 4294967295 [0xffffffff])) 0),
> (const_int 4294967295 [0xffffffff]))
> but 0xffffffff is not valid SImode CONST_INT, and unlike previously
> we no longer on WORD_REGISTER_OPERATIONS targets which have DImode
> word_mode optimize that into the op0, so the invalid constant is emitted
> into the IL and checking fails.
> 
> The following patch fixes that (and we optimize that & -1 away even earlier
> with that).
> 
> Could you please just quickly try to apply this patch, make in the stage3
> directory followed by
> make check-gcc RUNTESTFLAGS="... compile.exp='20070520-1.c ...'"
> (with all tests that regressed previously), whether this is the only spot
> or whether we need to fix some other place too?
> 
> 2023-04-13  Jakub Jelinek  <jakub@redhat.com>
> 
> 	* loop-iv.cc (iv_number_of_iterations): Use gen_int_mode instead
> 	of GEN_INT.
That fixes all the regressions and looks OK to me.

jeff