[PATCH] [InstCombine/InstSimplify] Move ashr optimization from Instcombine to Instsimplify

[suyog sarda]

My bad !! Yes, its -instsimplify




On Fri, Jun 27, 2014 at 11:21 PM, Nick Lewycky <nlewycky at google.com> wrote:

> On 27 June 2014 05:31, suyog <suyog.sarda at samsung.com> wrote:
>
>> Hi Nick,
>>
>> I modified the test case to use FileCheck.
>>
>> I also believe the test case is in accordance to what we taught
>> instsimplify as mentioned by Rahul above.
>> Also, this test case was the original one for instcombine, the code for
>> which we moved to instsimplify.
>>
>> Can you point out what's specific wrong in the test case? Your inputs are
>> most welcomed :)
>>
>>
>> http://reviews.llvm.org/D4102
>>
>> Files:
>>   lib/Analysis/InstructionSimplify.cpp
>>   lib/Transforms/InstCombine/InstCombineShifts.cpp
>>   test/Transforms/InstSimplify/ashr-nop.ll
>>
>>
>> Index: lib/Analysis/InstructionSimplify.cpp
>> ===================================================================
>> --- lib/Analysis/InstructionSimplify.cpp
>> +++ lib/Analysis/InstructionSimplify.cpp
>> @@ -1346,6 +1346,11 @@
>>
>>        cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
>>      return X;
>>
>> +  // Arithmetic shifting an all-sign-bit value is a no-op.
>> +  unsigned NumSignBits = ComputeNumSignBits(Op0);
>> +  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
>> +    return Op0;
>> +
>>    return nullptr;
>>  }
>>
>> Index: lib/Transforms/InstCombine/InstCombineShifts.cpp
>> ===================================================================
>> --- lib/Transforms/InstCombine/InstCombineShifts.cpp
>> +++ lib/Transforms/InstCombine/InstCombineShifts.cpp
>> @@ -815,10 +815,5 @@
>>
>>
>>  APInt::getSignBit(I.getType()->getScalarSizeInBits())))
>>      return BinaryOperator::CreateLShr(Op0, Op1);
>>
>> -  // Arithmetic shifting an all-sign-bit value is a no-op.
>> -  unsigned NumSignBits = ComputeNumSignBits(Op0);
>> -  if (NumSignBits == Op0->getType()->getScalarSizeInBits())
>> -    return ReplaceInstUsesWith(I, Op0);
>> -
>>    return nullptr;
>>  }
>> Index: test/Transforms/InstSimplify/ashr-nop.ll
>> ===================================================================
>> --- test/Transforms/InstSimplify/ashr-nop.ll
>> +++ test/Transforms/InstSimplify/ashr-nop.ll
>> @@ -0,0 +1,10 @@
>> +; RUN: opt < %s -instcombine -S | FileCheck %s
>>
>
> Did you mean -instsimplify?
>
>
>> +
>> +; CHECK-LABEL: @foo
>> +; CHECK-NOT: ashr
>>
>> +define i32 @foo(i32 %x) {
>> +  %o = and i32 %x, 1
>> +  %n = add i32 %o, -1
>> +  %t = ashr i32 %n, 17
>> +  ret i32 %t
>> +}
>>
>
>
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>


-- 
With regards,
Suyog Sarda
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