[llvm-commits] CVS: llvm/lib/Transforms/Scalar/IndVarSimplify.cpp

[Tanya Lattner]

Should this be added as a regression test?

-Tanya

On Jun 27, 2007, at 7:00 PM, Sheng Zhou wrote:

> Chris,
>
> Attached is the testcase, which will get:
>
> opt: /developer/home2/zsth/llvm-gcc-dev/HEAD/llvm/llvm/lib/VMCore/ 
> Constants.cpp:1559: static llvm::Constant*  
> llvm::ConstantExpr::getZExt(llvm::Constant*, const llvm::Type*):  
> Assertion `C->getType()->getPrimitiveSizeInBits() < Ty- 
> >getPrimitiveSizeInBits()&& "SrcTy must be smaller than DestTy for  
> ZExt!"' failed.
>
> The condition "IterationCount->getType() != LargestType" doesn't  
> mean the IterationCount->getType's bitwidth < LargestType's
> so, sometimes, (like in this testcase), it need a trunc not ext.  
> This patch is to fix it.
>
> Sheng
>
>
>
>   DOUT << "INDVARS: New CanIV: " << *IndVar;
>>
>>    if (!isa<SCEVCouldNotCompute>(IterationCount)) {
>> -    if (IterationCount->getType() != LargestType)
>> +    if (IterationCount->getType()->getPrimitiveSizeInBits() <
>> +        LargestType->getPrimitiveSizeInBits())
>>        IterationCount = SCEVZeroExtendExpr::get(IterationCount,   
>> LargestType);
>> +    else if (IterationCount->getType() != LargestType)
>> +      IterationCount = SCEVTruncateExpr::get(IterationCount,   
>> LargestType);
>>      if (Instruction *DI = LinearFunctionTestReplace(L,   
>> IterationCount,Rewriter))
>>        DeadInsts.insert(DI);
>>    }
>
>
> <testcase.bc>
> ; ModuleID = 'testcase.bc'
> target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32- 
> i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64"
> target triple = "i686-pc-linux-gnu"
>
> define i32 @testcase(i5 zext  %k) {
> entry:
> 	br label %bb2
>
> bb:		; preds = %bb2
> 	%tmp1 = add i32 %tmp2, %result		; <i32> [#uses=1]
> 	%indvar_next1 = add i5 %k_0, 1		; <i5> [#uses=1]
> 	br label %bb2
>
> bb2:		; preds = %bb, %entry
> 	%k_0 = phi i5 [ 0, %entry ], [ %indvar_next1, %bb ]		; <i5> [#uses=2]
> 	%result = phi i32 [ 0, %entry ], [ %tmp1, %bb ]		; <i32> [#uses=2]
> 	%tmp2 = zext i5 %k_0 to i32		; <i32> [#uses=1]
> 	%exitcond = icmp eq i32 %tmp2, 16		; <i1> [#uses=1]
> 	br i1 %exitcond, label %bb3, label %bb
>
> bb3:		; preds = %bb2
> 	ret i32 %result
> }
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