[llvm-commits] [llvm] r162751 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineMulDivRem.cpp test/Transforms/InstCombine/2012-08-28-udiv_ashl.ll

[Benjamin Kramer]

On 28.08.2012, at 15:39, Duncan Sands <baldrick at free.fr> wrote:

> Hi Benjamin,
>> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp (original)
>> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp Tue Aug 28 08:08:13 2012
>> @@ -464,11 +464,11 @@
>> 
>>    // Udiv ((Lshl x, C1) , C2) ->  x / (C2 * 1<<C1);
>>    if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
>> -    Value *X = 0, *C1 = 0;
>> -    if (match(Op0, m_LShr(m_Value(X), m_Value(C1))) && C2->getBitWidth() < 65) {
>> -      uint64_t NC = cast<ConstantInt>(C2)->getZExtValue() *
>> -                    (1<< cast<ConstantInt>(C1)->getZExtValue());
>> -      return BinaryOperator::CreateUDiv(X, ConstantInt::get(I.getType(), NC));
>> +    Value *X;
>> +    ConstantInt *C1;
>> +    if (match(Op0, m_LShr(m_Value(X), m_ConstantInt(C1)))) {
>> +      APInt NC = C2->getValue().shl(C1->getZExtValue());
> 
> shouldn't this use getLimitedValue just in case?

Thanks for noticing, fixed in r162755.

- Ben

> 
>> +      return BinaryOperator::CreateUDiv(X, Builder->getInt(NC));
>>      }
>>    }
>> 
>> @@ -545,11 +545,11 @@
>> 
>>    // Sdiv ((Ashl x, C1) , C2) ->  x / (C2 * 1<<C1);
>>    if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
>> -    Value *X = 0, *C1 = 0;
>> -    if (match(Op0, m_AShr(m_Value(X), m_Value(C1))) && C2->getBitWidth() < 65) {
>> -      uint64_t NC = cast<ConstantInt>(C2)->getZExtValue() *
>> -                    (1<< cast<ConstantInt>(C1)->getZExtValue());
>> -      return BinaryOperator::CreateSDiv(X, ConstantInt::get(I.getType(), NC));
>> +    Value *X;
>> +    ConstantInt *C1;
>> +    if (match(Op0, m_AShr(m_Value(X), m_ConstantInt(C1)))) {
> 
> Likewise.
> 
> Ciao, Duncan.
> 
>> +      APInt NC = C2->getValue().shl(C1->getZExtValue());
>> +      return BinaryOperator::CreateSDiv(X, Builder->getInt(NC));
>>      }
>>    }
> 
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