[llvm] r271810 - [InstCombine] allow vector constants for cast+icmp fold

[Sanjay Patel via llvm-commits]

Yes, good catch. 'CI' is actually performing triple duty here...it's an
abbreviation of 'CompareInst', 'CastInst' or 'ConstantInt' depending on
where it's used!

On Sat, Jun 4, 2016 at 4:47 PM, David Majnemer <david.majnemer at gmail.com>
wrote:

>
>
> On Sat, Jun 4, 2016 at 3:04 PM, Sanjay Patel via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: spatel
>> Date: Sat Jun  4 17:04:05 2016
>> New Revision: 271810
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=271810&view=rev
>> Log:
>> [InstCombine] allow vector constants for cast+icmp fold
>>
>> This is step 1 of unknown towards fixing PR28001:
>> https://llvm.org/bugs/show_bug.cgi?id=28001
>>
>>
>> Modified:
>>     llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
>>     llvm/trunk/test/Transforms/InstCombine/cast.ll
>>     llvm/trunk/test/Transforms/InstCombine/signed-comparison.ll
>>
>> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=271810&r1=271809&r2=271810&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
>> (original)
>> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Sat
>> Jun  4 17:04:05 2016
>> @@ -2439,7 +2439,7 @@ Instruction *InstCombiner::visitICmpInst
>>    }
>>
>>    // If we aren't dealing with a constant on the RHS, exit early.
>> -  auto *CI = dyn_cast<ConstantInt>(ICI.getOperand(1));
>> +  auto *CI = dyn_cast<Constant>(ICI.getOperand(1));
>>    if (!CI)
>>      return nullptr;
>>
>
> In InstCombine, variables named `CI` are typically `ConstantInt`.  I'd
> suggest renaming `CI` to `C`.
>
>
>>
>>
>> Modified: llvm/trunk/test/Transforms/InstCombine/cast.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/cast.ll?rev=271810&r1=271809&r2=271810&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/test/Transforms/InstCombine/cast.ll (original)
>> +++ llvm/trunk/test/Transforms/InstCombine/cast.ll Sat Jun  4 17:04:05
>> 2016
>> @@ -214,12 +214,9 @@ define i1 @test19(i32 %X) {
>>    ret i1 %Z
>>  }
>>
>> -; FIXME: Vector should be the same as scalar.
>> -
>>  define <2 x i1> @test19vec(<2 x i32> %X) {
>>  ; CHECK-LABEL: @test19vec(
>> -; CHECK-NEXT:    [[C:%.*]] = sext <2 x i32> %X to <2 x i64>
>> -; CHECK-NEXT:    [[Z:%.*]] = icmp slt <2 x i64> [[C]], <i64 12345, i64
>> 2147483647>
>> +; CHECK-NEXT:    [[Z:%.*]] = icmp slt <2 x i32> %X, <i32 12345, i32
>> 2147483647>
>>  ; CHECK-NEXT:    ret <2 x i1> [[Z]]
>>  ;
>>    %c = sext <2 x i32> %X to <2 x i64>
>> @@ -227,6 +224,16 @@ define <2 x i1> @test19vec(<2 x i32> %X)
>>    ret <2 x i1> %Z
>>  }
>>
>> +define <3 x i1> @test19vec2(<3 x i1> %X) {
>> +; CHECK-LABEL: @test19vec2(
>> +; CHECK-NEXT:    [[CMPEQ:%.*]] = icmp eq <3 x i1> %X, zeroinitializer
>> +; CHECK-NEXT:    ret <3 x i1> [[CMPEQ]]
>> +;
>> +  %sext = sext <3 x i1> %X to <3 x i32>
>> +  %cmpeq = icmp eq <3 x i32> %sext, zeroinitializer
>> +  ret <3 x i1> %cmpeq
>> +}
>> +
>>  define i1 @test20(i1 %B) {
>>  ; CHECK-LABEL: @test20(
>>  ; CHECK-NEXT:    ret i1 false
>>
>> Modified: llvm/trunk/test/Transforms/InstCombine/signed-comparison.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/signed-comparison.ll?rev=271810&r1=271809&r2=271810&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/test/Transforms/InstCombine/signed-comparison.ll (original)
>> +++ llvm/trunk/test/Transforms/InstCombine/signed-comparison.ll Sat Jun
>> 4 17:04:05 2016
>> @@ -13,12 +13,9 @@ define i1 @scalar_zext_slt(i16 %t4) {
>>    ret i1 %t6
>>  }
>>
>> -; FIXME: Vector compare should work the same as scalar.
>> -
>>  define <4 x i1> @vector_zext_slt(<4 x i16> %t4) {
>>  ; CHECK-LABEL: @vector_zext_slt(
>> -; CHECK-NEXT:    [[T5:%.*]] = zext <4 x i16> %t4 to <4 x i32>
>> -; CHECK-NEXT:    [[T6:%.*]] = icmp ult <4 x i32> [[T5]], <i32 500, i32
>> 0, i32 501, i32 65535>
>> +; CHECK-NEXT:    [[T6:%.*]] = icmp ult <4 x i16> %t4, <i16 500, i16 0,
>> i16 501, i16 -1>
>>  ; CHECK-NEXT:    ret <4 x i1> [[T6]]
>>  ;
>>    %t5 = zext <4 x i16> %t4 to <4 x i32>
>>
>>
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>>
>
>
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