llvm dev - Sep 2008 - [LLVMdev] Bad legalization?

I am getting an assert on a bad legalization.

Assertion failed: Result.getValueType() == Op.getValueType() &&
"Bad
legalization!", file ..\..\lib\CodeGen\SelectionDAG\LegalizeDAG.cpp,
line 3976

 

Can someone explain to me what this means in term of backend code
generation, how it might be occurring, and possible ways to fix this? I
don't see how the value type of an operation and the result being the
same can cause an issue.

The IR code in question is as follows:

 

define void @ test_unary_func_absolute_value(i32 %x, i32 addrspace(11)*
%result) {

entry:

        %call = tail call i32 (...)* @abs( i32 %x )             ; <i32>
[#uses=1]

        store i32 %call, i32 addrspace(11)* %result

        ret void

}

 

declare i32 @abs(...)

 

Micah Villmow

Systems Engineer

Advanced Technology & Performance

Advanced Micro Devices Inc.

4555 Great America Pkwy,

Santa Clara, CA. 95054

P: 408-572-6219

F: 408-572-6596

 

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On Mon, Sep 15, 2008 at 3:05 PM, Villmow, Micah <Micah.Villmow at amd.com>
wrote:
> I am getting an assert on a bad legalization.
>
> Assertion failed: Result.getValueType() == Op.getValueType() &&
"Bad
> legalization!", file ..\..\lib\CodeGen\SelectionDAG\LegalizeDAG.cpp,
line
> 3976
>
>
>
> Can someone explain to me what this means in term of backend code
> generation, how it might be occurring, and possible ways to fix this? I
> don't see how the value type of an operation and the result being the
same
> can cause an issue.
This roughly means that the type of the result of running
SelectionDAGLegalize::LegalizeOp is not the same as the type of the
argument to LegalizeOp.  Most likely, your custom legalization messing
up, although it's possible there's a bug in
SelectionDAGLegalize::LegalizeOp.

-Eli

On Sep 15, 2008, at 3:05 PM, Villmow, Micah wrote:
> I am getting an assert on a bad legalization.
> Assertion failed: Result.getValueType() == Op.getValueType() &&
"Bad
> legalization!", file ..\..\lib\CodeGen\SelectionDAG\LegalizeDAG.cpp,  
> line 3976
>
When you run into issues like this, it helps if you provide a bit more  
information. Please dump out Result, Op, DAG, and / or the DAG before  
legalization starts.

> Can someone explain to me what this means in term of backend code  
> generation, how it might be occurring, and possible ways to fix  
> this? I don’t see how the value type of an operation and the result  
> being the same can cause an issue.
Quite the opposite. It's asserting because the value types of op  
(before legalization) and Result (after) are different.

Evan
> The IR code in question is as follows:
>
> define void @ test_unary_func_absolute_value(i32 %x, i32  
> addrspace(11)* %result) {
> entry:
>         %call = tail call i32 (...)* @abs( i32 %x )             ;  
> <i32> [#uses=1]
>         store i32 %call, i32 addrspace(11)* %result
>         ret void
> }
>
> declare i32 @abs(...)
>
> Micah Villmow
> Systems Engineer
> Advanced Technology & Performance
> Advanced Micro Devices Inc.
> 4555 Great America Pkwy,
> Santa Clara, CA. 95054
> P: 408-572-6219
> F: 408-572-6596
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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It is conceivable that it's sensitive to the name "abs", try
changing
it.

On Sep 15, 2008, at 11:47 PMPDT, Evan Cheng wrote:
>
> On Sep 15, 2008, at 3:05 PM, Villmow, Micah wrote:
>
>> I am getting an assert on a bad legalization.
>> Assertion failed: Result.getValueType() == Op.getValueType() &&
>> "Bad legalization!", file ..\..\lib\CodeGen\SelectionDAG 
>> \LegalizeDAG.cpp, line 3976
>>
>
> When you run into issues like this, it helps if you provide a bit  
> more information. Please dump out Result, Op, DAG, and / or the DAG  
> before legalization starts.
>
>
>> Can someone explain to me what this means in term of backend code  
>> generation, how it might be occurring, and possible ways to fix  
>> this? I don’t see how the value type of an operation and the result  
>> being the same can cause an issue.
>
> Quite the opposite. It's asserting because the value types of op  
> (before legalization) and Result (after) are different.
>
> Evan
>
>> The IR code in question is as follows:
>>
>> define void @ test_unary_func_absolute_value(i32 %x, i32  
>> addrspace(11)* %result) {
>> entry:
>>         %call = tail call i32 (...)* @abs( i32 %x )             ;  
>> <i32> [#uses=1]
>>         store i32 %call, i32 addrspace(11)* %result
>>         ret void
>> }
>>
>> declare i32 @abs(...)
>>
>> Micah Villmow
>> Systems Engineer
>> Advanced Technology & Performance
>> Advanced Micro Devices Inc.
>> 4555 Great America Pkwy,
>> Santa Clara, CA. 95054
>> P: 408-572-6219
>> F: 408-572-6596
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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