[llvm] r293673 - InterleaveAccessPass: Avoid constructing invalid shuffle masks

[Hans Wennborg via llvm-commits]

It was requested on PR31823 that this should be merged to 4.0.

Merged in r293805.

(I first merged r293309, which moved the tests, in r293804.)


On Tue, Jan 31, 2017 at 10:37 AM, Matthias Braun via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: matze
> Date: Tue Jan 31 12:37:53 2017
> New Revision: 293673
>
> URL: http://llvm.org/viewvc/llvm-project?rev=293673&view=rev
> Log:
> InterleaveAccessPass: Avoid constructing invalid shuffle masks
>
> Fix a bug where we would construct shufflevector instructions addressing
> invalid elements.
>
> Differential Revision: https://reviews.llvm.org/D29313
>
> Modified:
>     llvm/trunk/lib/CodeGen/InterleavedAccessPass.cpp
>     llvm/trunk/test/Transforms/InterleavedAccess/AArch64/interleaved-accesses.ll
>     llvm/trunk/test/Transforms/InterleavedAccess/ARM/interleaved-accesses.ll
>
> Modified: llvm/trunk/lib/CodeGen/InterleavedAccessPass.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/InterleavedAccessPass.cpp?rev=293673&r1=293672&r2=293673&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/InterleavedAccessPass.cpp (original)
> +++ llvm/trunk/lib/CodeGen/InterleavedAccessPass.cpp Tue Jan 31 12:37:53 2017
> @@ -174,7 +174,7 @@ static bool isDeInterleaveMask(ArrayRef<
>  /// I.e. <0, LaneLen, ... , LaneLen*(Factor - 1), 1, LaneLen + 1, ...>
>  /// E.g. For a Factor of 2 (LaneLen=4): <0, 4, 1, 5, 2, 6, 3, 7>
>  static bool isReInterleaveMask(ArrayRef<int> Mask, unsigned &Factor,
> -                               unsigned MaxFactor) {
> +                               unsigned MaxFactor, unsigned OpNumElts) {
>    unsigned NumElts = Mask.size();
>    if (NumElts < 4)
>      return false;
> @@ -246,6 +246,9 @@ static bool isReInterleaveMask(ArrayRef<
>
>        if (StartMask < 0)
>          break;
> +      // We must stay within the vectors; This case can happen with undefs.
> +      if (StartMask + LaneLen > OpNumElts*2)
> +        break;
>      }
>
>      // Found an interleaved mask of current factor.
> @@ -406,7 +409,8 @@ bool InterleavedAccess::lowerInterleaved
>
>    // Check if the shufflevector is RE-interleave shuffle.
>    unsigned Factor;
> -  if (!isReInterleaveMask(SVI->getShuffleMask(), Factor, MaxFactor))
> +  unsigned OpNumElts = SVI->getOperand(0)->getType()->getVectorNumElements();
> +  if (!isReInterleaveMask(SVI->getShuffleMask(), Factor, MaxFactor, OpNumElts))
>      return false;
>
>    DEBUG(dbgs() << "IA: Found an interleaved store: " << *SI << "\n");
>
> Modified: llvm/trunk/test/Transforms/InterleavedAccess/AArch64/interleaved-accesses.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InterleavedAccess/AArch64/interleaved-accesses.ll?rev=293673&r1=293672&r2=293673&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/InterleavedAccess/AArch64/interleaved-accesses.ll (original)
> +++ llvm/trunk/test/Transforms/InterleavedAccess/AArch64/interleaved-accesses.ll Tue Jan 31 12:37:53 2017
> @@ -547,3 +547,21 @@ define void @store_general_mask_factor3_
>    store <12 x i32> %interleaved.vec, <12 x i32>* %ptr, align 4
>    ret void
>  }
> +
> + at g = external global <4 x float>
> +
> +; The following does not give a valid interleaved store
> +; NEON-LABEL: define void @no_interleave
> +; NEON-NOT: call void @llvm.aarch64.neon.st2
> +; NEON: shufflevector
> +; NEON: store
> +; NEON: ret void
> +; NO_NEON-LABEL: define void @no_interleave
> +; NO_NEON: shufflevector
> +; NO_NEON: store
> +; NO_NEON: ret void
> +define void @no_interleave(<4 x float> %a0) {
> +  %v0 = shufflevector <4 x float> %a0, <4 x float> %a0, <4 x i32> <i32 0, i32 3, i32 7, i32 undef>
> +  store <4 x float> %v0, <4 x float>* @g, align 16
> +  ret void
> +}
>
> Modified: llvm/trunk/test/Transforms/InterleavedAccess/ARM/interleaved-accesses.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InterleavedAccess/ARM/interleaved-accesses.ll?rev=293673&r1=293672&r2=293673&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/InterleavedAccess/ARM/interleaved-accesses.ll (original)
> +++ llvm/trunk/test/Transforms/InterleavedAccess/ARM/interleaved-accesses.ll Tue Jan 31 12:37:53 2017
> @@ -626,3 +626,21 @@ define void @store_general_mask_factor3_
>    store <12 x i32> %interleaved.vec, <12 x i32>* %ptr, align 4
>    ret void
>  }
> +
> + at g = external global <4 x float>
> +
> +; The following does not give a valid interleaved store
> +; NEON-LABEL: define void @no_interleave
> +; NEON-NOT: call void @llvm.arm.neon.vst2
> +; NEON: shufflevector
> +; NEON: store
> +; NEON: ret void
> +; NO_NEON-LABEL: define void @no_interleave
> +; NO_NEON: shufflevector
> +; NO_NEON: store
> +; NO_NEON: ret void
> +define void @no_interleave(<4 x float> %a0) {
> +  %v0 = shufflevector <4 x float> %a0, <4 x float> %a0, <4 x i32> <i32 0, i32 7, i32 1, i32 undef>
> +  store <4 x float> %v0, <4 x float>* @g, align 16
> +  ret void
> +}
>
>
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