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

[Quentin Colombet]

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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>>