[PATCH][RTL-ifcvt] PR rtl-optimization/68506: Fix emitting order of insns in IF-THEN-JOIN case

[Richard Biener]

On Fri, Nov 27, 2015 at 10:44 AM, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
>
> On 26/11/15 16:54, Kyrill Tkachov wrote:
>>
>>
>> On 26/11/15 16:49, Bernd Schmidt wrote:
>>>
>>> On 11/26/2015 05:45 PM, Kyrill Tkachov wrote:
>>>>
>>>>          that doesn't help, punt.  */
>>>>
>>>> -  modified_in_a = emit_a != NULL_RTX && modified_in_p (orig_b, emit_a);
>>>>     if (tmp_b && then_bb)
>>>>       {
>>>
>>> These bits I thought would be part of a followup patch (which would also
>>> guard against single_set problems), and as I mentioned I'd rather have a
>>> checking assert.
>>
>> Yes, you're right. I have the checking_assert statement in the followup
>> that I've been testing.
>> I'll move the deletion of these two statements there as well to minimise
>> the changes to this patch.
>>
>> I'll move these bits to that patch, re-build cc1 and commit.
>>
>
> Here it is.
> I'm committing this to trunk.

I think this causes

FAIL: gcc.c-torture/execute/20050124-1.c   -O2  (internal compiler error)
FAIL: gcc.c-torture/execute/20050124-1.c   -O2  (test for excess errors)
WARNING: gcc.c-torture/execute/20050124-1.c   -O2  compilation failed to produce
 executable
FAIL: gcc.c-torture/execute/20050124-1.c   -O2 -flto -fno-use-linker-plugin -flt
o-partition=none  (internal compiler error)
FAIL: gcc.c-torture/execute/20050124-1.c   -O2 -flto -fno-use-linker-plugin -flt
o-partition=none  (test for excess errors)
....

/space/rguenther/src/svn/trunk2/gcc/testsuite/gcc.c-torture/execute/20050124-1.c:19:1:
internal compiler error: in noce_try_cmove_arith, at ifcvt.c:2180^M
0x11f919d noce_try_cmove_arith^M
        /space/rguenther/src/svn/trunk2/gcc/ifcvt.c:2180^M
0x11fb93f noce_process_if_block^M
        /space/rguenther/src/svn/trunk2/gcc/ifcvt.c:3525^M
0x11fdd0e noce_find_if_block^M
        /space/rguenther/src/svn/trunk2/gcc/ifcvt.c:3974^M
0x11fdd0e find_if_header^M
        /space/rguenther/src/svn/trunk2/gcc/ifcvt.c:4179^M
0x11fdd0e if_convert^M
        /space/rguenther/src/svn/trunk2/gcc/ifcvt.c:5326^M
0x11ff32d execute^M


on x86_64 with -m64 and -m32.

Richard.

> Thanks,
> Kyrill
>
> 2015-11-26  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>
>     PR rtl-optimization/68506
>     * ifcvt.c (noce_try_cmove_arith): Try emitting the else basic block
>     first if emit_a exists or then_bb modifies 'b'.  Reindent if-else
>     blocks.
>
> 2015-11-26  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>
>     PR rtl-optimization/68506
>     * gcc.c-torture/execute/pr68506.c: New test.
>
>> Thanks for your guidance,
>> Kyrill
>>
>>> So take these deletions out and leave them for the followup, and the
>>> patch is ok everywhere. No need for a full retest given that practically the
>>> same patch has been tested already, just make sure you can build cc1.
>>>
>>>
>>> Bernd
>>>
>>
>