[llvm-commits] [llvm] r147308 - in /llvm/trunk: lib/Target/X86/X86ISelLowering.cpp test/CodeGen/X86/avx-shuffle.ll

[Chad Rosier]

Hi Elena,
Just a few comments below.

On Dec 28, 2011, at 12:14 AM, Elena Demikhovsky wrote:

> Author: delena
> Date: Wed Dec 28 02:14:01 2011
> New Revision: 147308
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=147308&view=rev
> Log:
> Fixed a bug in LowerVECTOR_SHUFFLE and LowerBUILD_VECTOR.
> Matching MOVLP mask for AVX (265-bit vectors) was wrong.
> The failure was detected by conformance tests.

As far as I can tell this patch is addressing two bugs, one in LowerBUILD_VECTOR and another with LowerVECTOR_SHUFFLE/MOVLP.  These should really be fixed in two separate commits.

> 
> Modified:
>    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
>    llvm/trunk/test/CodeGen/X86/avx-shuffle.ll
> 
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=147308&r1=147307&r2=147308&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Wed Dec 28 02:14:01 2011
> @@ -3448,6 +3448,11 @@
> /// isMOVLPMask - Return true if the specified VECTOR_SHUFFLE operand
> /// specifies a shuffle of elements that is suitable for input to MOVLP{S|D}.
> bool X86::isMOVLPMask(ShuffleVectorSDNode *N) {
> +  EVT VT = N->getValueType(0);
> +
> +  if (VT.getSizeInBits() != 128)
> +    return false;
> +

I'm not sure I agree with the approach taken here...

>   unsigned NumElems = N->getValueType(0).getVectorNumElements();
> 
>   if (NumElems != 2 && NumElems != 4)
> @@ -3666,6 +3671,8 @@
> static bool isMOVLMask(const SmallVectorImpl<int> &Mask, EVT VT) {
>   if (VT.getVectorElementType().getSizeInBits() < 32)
>     return false;
> +  if (VT.getSizeInBits() == 256)
> +    return false;

..and here.  Aren't these functions behaving correctly?  I believe the real problem is the code that is predicated upon these functions; they don't fully support codegen when AVX is enabled.

And one moot point..  The conditional statements that checks the size of the vectors could be more consistent (i.e., both (VT.getSizeInBits != 128) or (VT.getSizeInBits != 128), but not a combination of the two).

>   int NumElts = VT.getVectorNumElements();
> 
> @@ -5158,16 +5165,30 @@
>         return DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Item);
>       } else if (ExtVT == MVT::i32 || ExtVT == MVT::f32 || ExtVT == MVT::f64 ||
>           (ExtVT == MVT::i64 && Subtarget->is64Bit())) {
> +        if (VT.getSizeInBits() == 256) {
> +          
> +          EVT VT128 = EVT::getVectorVT(*DAG.getContext(), ExtVT, NumElems / 2);
> +          Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT128, Item);
> +          SDValue ZeroVec = getZeroVector(VT, true, DAG, dl);              
> +          return Insert128BitVector(ZeroVec, Item, DAG.getConstant(0, MVT::i32),
> +                              DAG, dl);
> +        }
>         Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Item);
>         // Turn it into a MOVL (i.e. movss, movsd, or movd) to a zero vector.
>         return getShuffleVectorZeroOrUndef(Item, 0, true,Subtarget->hasXMMInt(),
>                                            DAG);
>       } else if (ExtVT == MVT::i16 || ExtVT == MVT::i8) {
>         Item = DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i32, Item);
> -        unsigned NumBits = VT.getSizeInBits();
> -        assert((NumBits == 128 || NumBits == 256) && 
> -               "Expected an SSE or AVX value type!");
> -        EVT MiddleVT = NumBits == 128 ? MVT::v4i32 : MVT::v8i32;
> +        if (VT.getSizeInBits() == 256) {
> +          
> +          EVT VT128 = EVT::getVectorVT(*DAG.getContext(), ExtVT, NumElems / 2);
> +          Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT128, Item);
> +          SDValue ZeroVec = getZeroVector(VT, true, DAG, dl);              
> +          return Insert128BitVector(ZeroVec, Item, DAG.getConstant(0, MVT::i32),
> +                              DAG, dl);
> +        }
> +        assert (VT.getSizeInBits() == 128 || "Expected an SSE value type!");
> +        EVT MiddleVT = MVT::v4i32;
>         Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, MiddleVT, Item);
>         Item = getShuffleVectorZeroOrUndef(Item, 0, true,
>                                            Subtarget->hasXMMInt(), DAG);
> 
> Modified: llvm/trunk/test/CodeGen/X86/avx-shuffle.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/avx-shuffle.ll?rev=147308&r1=147307&r2=147308&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/avx-shuffle.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/avx-shuffle.ll Wed Dec 28 02:14:01 2011
> @@ -13,8 +13,22 @@
> define <3 x i64> @test2(<2 x i64> %v) nounwind readnone {
> ; CHECK: test2:
> ; CHECK: vxorpd
> -; CHECK: vmovsd
> +; CHECK: vperm2f128
>   %1 = shufflevector <2 x i64> %v, <2 x i64> %v, <3 x i32> <i32 0, i32 1, i32 undef>
>   %2 = shufflevector <3 x i64> zeroinitializer, <3 x i64> %1, <3 x i32> <i32 3, i32 4, i32 2>
>   ret <3 x i64> %2
> }
> +
> +define <4 x i64> @test3(<4 x i64> %a, <4 x i64> %b) nounwind {
> +  %c = shufflevector <4 x i64> %a, <4 x i64> %b, <4 x i32> <i32 4, i32 5, i32 2, i32 undef>
> +  ret <4 x i64> %c
> +; CHECK: test3:
> +; CHECK: vperm2f128
> +}
> +
> +define <8 x float> @test4(float %a) nounwind {
> +  %b = insertelement <8 x float> zeroinitializer, float %a, i32 0
> +  ret <8 x float> %b
> +; CHECK: test4:
> +; CHECK: vinsertf128
> +}
> \ No newline at end of file
> 

Please make sure your test case ends with a newline.  This was fixed in r147481.

 Chad

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