[llvm] r221820 - [CodeGenPrepare][AArch64] Fix a TLI legality check on iPTR to use a lowered instead.

[Ahmed Bougacha]

The others went into r221827, with an explanation in case there's a
problem some day.

- Ahmed


On Wed, Nov 12, 2014 at 2:54 PM, Quentin Colombet <qcolombet at apple.com> wrote:
>
> On Nov 12, 2014, at 2:47 PM, Ahmed Bougacha <ahmed.bougacha at gmail.com> wrote:
>
>> On Wed, Nov 12, 2014 at 2:35 PM, Quentin Colombet <qcolombet at apple.com> wrote:
>>> Hi Ahmed,
>>>
>>> We have other uses of this construction in CodeGenPrepare, shouldn’t we fix those too?
>>
>> Yes, I was actually looking at them to try and come up with testcases.
>>
>> There is one result of EVT::getEVT() that is passed to
>> allowsMisalignedMemoryAccesses, and that one is the target's
>> responsibility, and wouldn't hit the assert anyway.
>>
>> There are two that involve TLI legality checks. For both I don't think
>> it's possible for them to fail as is:
>> - one only looks at binary operators, and we don't have any of those
>> on pointers IIRC.
>> - the other looks at extensions only
>>
>> I'm changing them just in case (for the first, there's actually a
>> comment saying that we should also look at cast operators, and in that
>> case we will hit the same problem), but they won't have test cases.
>
> Fair enough, thanks!
>
> Q.
>
>>
>> Anyway, thanks for having a look, I'm committing the other changes as we speak.
>>
>> -Ahmed
>>
>>> Thanks,
>>> Quentin
>>>
>>> On Nov 12, 2014, at 2:16 PM, Ahmed Bougacha <ahmed.bougacha at gmail.com> wrote:
>>>
>>>> Author: ab
>>>> Date: Wed Nov 12 16:16:55 2014
>>>> New Revision: 221820
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=221820&view=rev
>>>> Log:
>>>> [CodeGenPrepare][AArch64] Fix a TLI legality check on iPTR to use a lowered instead.
>>>>
>>>> Fixes PR21548.  Related to PR20474.
>>>>
>>>>
>>>> Modified:
>>>>   llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
>>>>   llvm/trunk/test/Transforms/CodeGenPrepare/AArch64/trunc-weird-user.ll
>>>>
>>>> Modified: llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp?rev=221820&r1=221819&r2=221820&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp (original)
>>>> +++ llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp Wed Nov 12 16:16:55 2014
>>>> @@ -682,8 +682,8 @@ SinkShiftAndTruncate(BinaryOperator *Shi
>>>>    // FIXME: always querying the result type is just an
>>>>    // approximation; some nodes' legality is determined by the
>>>>    // operand or other means. There's no good way to find out though.
>>>> -    if (TLI.isOperationLegalOrCustom(ISDOpcode,
>>>> -                                     EVT::getEVT(TruncUser->getType(), true)))
>>>> +    if (TLI.isOperationLegalOrCustom(
>>>> +            ISDOpcode, TLI.getValueType(TruncUser->getType(), true)))
>>>>      continue;
>>>>
>>>>    // Don't bother for PHI nodes.
>>>>
>>>> Modified: llvm/trunk/test/Transforms/CodeGenPrepare/AArch64/trunc-weird-user.ll
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/CodeGenPrepare/AArch64/trunc-weird-user.ll?rev=221820&r1=221819&r2=221820&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/test/Transforms/CodeGenPrepare/AArch64/trunc-weird-user.ll (original)
>>>> +++ llvm/trunk/test/Transforms/CodeGenPrepare/AArch64/trunc-weird-user.ll Wed Nov 12 16:16:55 2014
>>>> @@ -15,3 +15,22 @@ define %foo @test_merge(i32 %in) {
>>>>  %struct = insertvalue %foo undef, i8 %byte, 0
>>>>  ret %"foo" %struct
>>>> }
>>>> +
>>>> +define i64* @test_merge_PR21548(i32 %a, i64* %p1, i64* %p2, i64* %p3) {
>>>> +; CHECK-LABEL: @test_merge_PR21548
>>>> +  %as = lshr i32 %a, 3
>>>> +  %Tr = trunc i32 %as to i1
>>>> +  br i1 %Tr, label %BB2, label %BB3
>>>> +
>>>> +BB2:
>>>> +  ; Similarly to above:
>>>> +  ; CodeGenPrepare was requesting the EVT for i8* to determine
>>>> +  ; whether the select user of the trunc was legal. This asserted.
>>>> +
>>>> +; CHECK: select i1 {{%.*}}, i64* %p1, i64* %p2
>>>> +  %p = select i1 %Tr, i64* %p1, i64* %p2
>>>> +  ret i64* %p
>>>> +
>>>> +BB3:
>>>> +  ret i64* %p3
>>>> +}
>>>>
>>>>
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>>>
>