[llvm] r213799 - X86: restrict combine to when type sizes are safe.

Bill Wendling isanbard at gmail.com
Mon Aug 4 22:29:11 PDT 2014


Done. Thanks!

-bw

On Aug 4, 2014, at 11:19 AM, Jim Grosbach <grosbach at apple.com> wrote:

>> 
>> On Aug 3, 2014, at 9:07 AM, Saleem Abdulrasool <compnerd at compnerd.org> wrote:
>> 
>> On Wed, Jul 23, 2014 at 1:41 PM, Jim Grosbach <grosbach at apple.com> wrote:
>> Author: grosbach
>> Date: Wed Jul 23 15:41:38 2014
>> New Revision: 213799
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=213799&view=rev
>> Log:
>> X86: restrict combine to when type sizes are safe.
>> 
>> The folding of unary operations through a vector compare and mask operation
>> is only safe if the unary operation result is of the same size as its input.
>> For example, it's not safe for [su]itofp from v4i32 to v4f64.
>> 
>> Modified:
>>     llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
>>     llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
>>     llvm/trunk/test/CodeGen/AArch64/arm64-setcc-int-to-fp-combine.ll
>>     llvm/trunk/test/CodeGen/X86/x86-setcc-int-to-fp-combine.ll
>> 
>> Should this get pulled into the 3.5 branch?
> 
> Yes. Good catch.
> 
>>  
>> Modified: llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp?rev=213799&r1=213798&r2=213799&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp (original)
>> +++ llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp Wed Jul 23 15:41:38 2014
>> @@ -6492,11 +6492,13 @@ static SDValue performVectorCompareAndMa
>>    //       AND(VECTOR_CMP(x,y), constant2)
>>    //    constant2 = UNARYOP(constant)
>> 
>> -  // Early exit if this isn't a vector operation or if the operand of the
>> -  // unary operation isn't a bitwise AND.
>> +  // Early exit if this isn't a vector operation, the operand of the
>> +  // unary operation isn't a bitwise AND, or if the sizes of the operations
>> +  // aren't the same.
>>    EVT VT = N->getValueType(0);
>>    if (!VT.isVector() || N->getOperand(0)->getOpcode() != ISD::AND ||
>> -      N->getOperand(0)->getOperand(0)->getOpcode() != ISD::SETCC)
>> +      N->getOperand(0)->getOperand(0)->getOpcode() != ISD::SETCC ||
>> +      VT.getSizeInBits() != N->getOperand(0)->getValueType(0).getSizeInBits())
>>      return SDValue();
>> 
>>    // Now check that the other operand of the AND is a constant splat. We could
>> 
>> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=213799&r1=213798&r2=213799&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
>> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Wed Jul 23 15:41:38 2014
>> @@ -21806,11 +21806,13 @@ static SDValue performVectorCompareAndMa
>>    //       AND(VECTOR_CMP(x,y), constant2)
>>    //    constant2 = UNARYOP(constant)
>> 
>> -  // Early exit if this isn't a vector operation or if the operand of the
>> -  // unary operation isn't a bitwise AND.
>> +  // Early exit if this isn't a vector operation, the operand of the
>> +  // unary operation isn't a bitwise AND, or if the sizes of the operations
>> +  // aren't the same.
>>    EVT VT = N->getValueType(0);
>>    if (!VT.isVector() || N->getOperand(0)->getOpcode() != ISD::AND ||
>> -      N->getOperand(0)->getOperand(0)->getOpcode() != ISD::SETCC)
>> +      N->getOperand(0)->getOperand(0)->getOpcode() != ISD::SETCC ||
>> +      VT.getSizeInBits() != N->getOperand(0)->getValueType(0).getSizeInBits())
>>      return SDValue();
>> 
>>    // Now check that the other operand of the AND is a constant splat. We could
>> 
>> Modified: llvm/trunk/test/CodeGen/AArch64/arm64-setcc-int-to-fp-combine.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/arm64-setcc-int-to-fp-combine.ll?rev=213799&r1=213798&r2=213799&view=diff
>> ==============================================================================
>> --- llvm/trunk/test/CodeGen/AArch64/arm64-setcc-int-to-fp-combine.ll (original)
>> +++ llvm/trunk/test/CodeGen/AArch64/arm64-setcc-int-to-fp-combine.ll Wed Jul 23 15:41:38 2014
>> @@ -11,3 +11,17 @@ define <4 x float> @foo(<4 x float> %val
>>    %result = sitofp <4 x i32> %ext to <4 x float>
>>    ret <4 x float> %result
>>  }
>> +; Make sure the operation doesn't try to get folded when the sizes don't match,
>> +; as that ends up crashing later when trying to form a bitcast operation for
>> +; the folded nodes.
>> +define void @foo1(<4 x float> %val, <4 x float> %test, <4 x double>* %p) nounwind {
>> +; CHECK-LABEL: foo1:
>> +; CHECK: movi.4s
>> +; CHECK: scvtf.2d
>> +; CHECK: scvtf.2d
>> +  %cmp = fcmp oeq <4 x float> %val, %test
>> +  %ext = zext <4 x i1> %cmp to <4 x i32>
>> +  %result = sitofp <4 x i32> %ext to <4 x double>
>> +  store <4 x double> %result, <4 x double>* %p
>> +  ret void
>> +}
>> 
>> Modified: llvm/trunk/test/CodeGen/X86/x86-setcc-int-to-fp-combine.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/x86-setcc-int-to-fp-combine.ll?rev=213799&r1=213798&r2=213799&view=diff
>> ==============================================================================
>> --- llvm/trunk/test/CodeGen/X86/x86-setcc-int-to-fp-combine.ll (original)
>> +++ llvm/trunk/test/CodeGen/X86/x86-setcc-int-to-fp-combine.ll Wed Jul 23 15:41:38 2014
>> @@ -17,14 +17,38 @@ define <4 x float> @foo(<4 x float> %val
>>    ret <4 x float> %result
>>  }
>> 
>> -define void @bar(<4 x float>* noalias %result) nounwind {
>> +; Make sure the operation doesn't try to get folded when the sizes don't match,
>> +; as that ends up crashing later when trying to form a bitcast operation for
>> +; the folded nodes.
>> +define void @foo1(<4 x float> %val, <4 x float> %test, <4 x double>* %p) nounwind {
>>  ; CHECK-LABEL: LCPI1_0:
>> +; CHECK-NEXT: .long 1                       ## 0x1
>> +; CHECK-NEXT: .long 1                       ## 0x1
>> +; CHECK-NEXT: .long 1                       ## 0x1
>> +; CHECK-NEXT: .long 1                       ## 0x1
>> +; CHECK-LABEL: foo1:
>> +;   FIXME: The operation gets scalarized. If/when the compiler learns to better
>> +;          use [V]CVTDQ2PD, this will need updated.
>> +; CHECK: cvtsi2sdq
>> +; CHECK: cvtsi2sdq
>> +; CHECK: cvtsi2sdq
>> +; CHECK: cvtsi2sdq
>> +  %cmp = fcmp oeq <4 x float> %val, %test
>> +  %ext = zext <4 x i1> %cmp to <4 x i32>
>> +  %result = sitofp <4 x i32> %ext to <4 x double>
>> +  store <4 x double> %result, <4 x double>* %p
>> +  ret void
>> +}
>> +
>> +; Also test the general purpose constant folding of int->fp.
>> +define void @foo2(<4 x float>* noalias %result) nounwind {
>> +; CHECK-LABEL: LCPI2_0:
>>  ; CHECK-NEXT: .long 1082130432              ## float 4.000000e+00
>>  ; CHECK-NEXT: .long 1084227584              ## float 5.000000e+00
>>  ; CHECK-NEXT: .long 1086324736              ## float 6.000000e+00
>>  ; CHECK-NEXT: .long 1088421888              ## float 7.000000e+00
>> -; CHECK-LABEL: bar:
>> -; CHECK:  movaps LCPI1_0(%rip), %xmm0
>> +; CHECK-LABEL: foo2:
>> +; CHECK:  movaps LCPI2_0(%rip), %xmm0
>> 
>>    %val = uitofp <4 x i32> <i32 4, i32 5, i32 6, i32 7> to <4 x float>
>>    store <4 x float> %val, <4 x float>* %result
>> 
>> 
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>> 
>> 
>> 
>> -- 
>> Saleem Abdulrasool
>> compnerd (at) compnerd (dot) org

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