[llvm] r353082 - [WarnMissedTransforms] Do not warn about already vectorized loops.

[Hans Wennborg via llvm-commits]

Merged to 8.0 in r353166. Please let me know if there are any follow-ups.

Thanks,
Hans

On Mon, Feb 4, 2019 at 8:55 PM Michael Kruse via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
>
> Author: meinersbur
> Date: Mon Feb  4 11:55:59 2019
> New Revision: 353082
>
> URL: http://llvm.org/viewvc/llvm-project?rev=353082&view=rev
> Log:
> [WarnMissedTransforms] Do not warn about already vectorized loops.
>
> LoopVectorize adds llvm.loop.isvectorized, but leaves
> llvm.loop.vectorize.enable. Do not consider such a loop for user-forced
> vectorization since vectorization already happened -- by prioritizing
> llvm.loop.isvectorized except for TM_SuppressedByUser.
>
> Fixes http://llvm.org/PR40546
>
> Differential Revision: https://reviews.llvm.org/D57542
>
> Added:
>     llvm/trunk/test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll
> Modified:
>     llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp
>
> Modified: llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp?rev=353082&r1=353081&r2=353082&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/LoopUtils.cpp Mon Feb  4 11:55:59 2019
> @@ -378,17 +378,17 @@ TransformationMode llvm::hasVectorizeTra
>    Optional<int> InterleaveCount =
>        getOptionalIntLoopAttribute(L, "llvm.loop.interleave.count");
>
> -  if (Enable == true) {
> -    // 'Forcing' vector width and interleave count to one effectively disables
> -    // this tranformation.
> -    if (VectorizeWidth == 1 && InterleaveCount == 1)
> -      return TM_SuppressedByUser;
> -    return TM_ForcedByUser;
> -  }
> +  // 'Forcing' vector width and interleave count to one effectively disables
> +  // this tranformation.
> +  if (Enable == true && VectorizeWidth == 1 && InterleaveCount == 1)
> +    return TM_SuppressedByUser;
>
>    if (getBooleanLoopAttribute(L, "llvm.loop.isvectorized"))
>      return TM_Disable;
>
> +  if (Enable == true)
> +    return TM_ForcedByUser;
> +
>    if (VectorizeWidth == 1 && InterleaveCount == 1)
>      return TM_Disable;
>
>
> Added: llvm/trunk/test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll?rev=353082&view=auto
> ==============================================================================
> --- llvm/trunk/test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll (added)
> +++ llvm/trunk/test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll Mon Feb  4 11:55:59 2019
> @@ -0,0 +1,33 @@
> +; RUN: opt -transform-warning -disable-output < %s 2>&1 | FileCheck -allow-empty %s
> +;
> +; llvm.org/PR40546
> +; Do not warn about about leftover llvm.loop.vectorize.enable for already
> +; vectorized loops.
> +
> +target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
> +
> +define void @test(i32 %n) {
> +entry:
> +  %cmp = icmp eq i32 %n, 0
> +  br i1 %cmp, label %simd.if.end, label %omp.inner.for.body.preheader
> +
> +omp.inner.for.body.preheader:
> +  %wide.trip.count = zext i32 %n to i64
> +  br label %omp.inner.for.body
> +
> +omp.inner.for.body:
> +  %indvars.iv = phi i64 [ 0, %omp.inner.for.body.preheader ], [ %indvars.iv.next, %omp.inner.for.body ]
> +  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
> +  %exitcond = icmp eq i64 %indvars.iv.next, %wide.trip.count
> +  br i1 %exitcond, label %simd.if.end, label %omp.inner.for.body, !llvm.loop !0
> +
> +simd.if.end:
> +  ret void
> +}
> +
> +!0 = distinct !{!0, !1, !2}
> +!1 = !{!"llvm.loop.vectorize.enable", i1 true}
> +!2 = !{!"llvm.loop.isvectorized"}
> +
> +
> +; CHECK-NOT: loop not vectorized
>
>
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