Re: [PATCH] Fix PR80334

[Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>]

Hi Richard,

> On Thu, 6 Apr 2017, Rainer Orth wrote:
>
>> Hi Richard,
>> 
>> > The following patch makes sure to preserve (mis-)alignment of memory
>> > references when IVOPTs generates TARGET_MEM_REFs for them.
>> >
>> > Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
>> >
>> > Richard.
>> >
>> > 2017-04-06  Richard Biener  <rguenther@suse.de>
>> >
>> > 	PR tree-optimization/80334
>> > 	* tree-ssa-loop-ivopts.c (rewrite_use_address): Properly
>> > 	preserve alignment of accesses.
>> >
>> > 	* g++.dg/torture/pr80334.C: New testcase.
>> 
>> the new testcase FAILs on 32-bit Solaris/SPARC:
>> 
>> +FAIL: g++.dg/torture/pr80334.C   -O0  (test for excess errors)
>> +FAIL: g++.dg/torture/pr80334.C   -O1  (test for excess errors)
>> +FAIL: g++.dg/torture/pr80334.C   -O2  (test for excess errors)
>> +FAIL: g++.dg/torture/pr80334.C   -O2 -flto  (test for excess errors)
>> +FAIL: g++.dg/torture/pr80334.C -O2 -flto -flto-partition=none (test for
>> exce
>> ss errors)
>> +FAIL: g++.dg/torture/pr80334.C -O3 -fomit-frame-pointer -funroll-loops
>> -fpeel
>> -loops -ftracer -finline-functions  (test for excess errors)
>> +FAIL: g++.dg/torture/pr80334.C   -O3 -g  (test for excess errors)
>> +FAIL: g++.dg/torture/pr80334.C   -Os  (test for excess errors)
>> 
>> Excess errors:
>> /vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.dg/torture/pr80334.C:11:20:
>> warning: requested alignment 16 is larger than 8 [-Wattributes]
>
> Any suggestion how to mitigate that?  Possible solution includes
> adding { target { ! ... } } to dg-do run.

No idea.  However, according to gcc-testresults there are other
failures: s390-ibm-inux-gnu and s390x-ibm-linux-gnu so far.

This might argue against just excluding a random list of failing targets.

	Rainer

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Rainer Orth, Center for Biotechnology, Bielefeld University