[llvm] 427520a - Revert "[InstCombine] factorize min/max intrinsic ops with common operand"

Thu Aug 12 12:42:16 PDT 2021

Reproducer?

On Thu, Aug 12, 2021 at 10:36 PM Amy Huang via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
>
>
> Author: Amy Huang
> Date: 2021-08-12T12:36:25-07:00
> New Revision: 427520a8fa09cc9e65e3ee118be7cc5f1ac21d10
>
> URL: https://github.com/llvm/llvm-project/commit/427520a8fa09cc9e65e3ee118be7cc5f1ac21d10
> DIFF: https://github.com/llvm/llvm-project/commit/427520a8fa09cc9e65e3ee118be7cc5f1ac21d10.diff
>
> LOG: Revert "[InstCombine] factorize min/max intrinsic ops with common operand"
>
> This reverts commit 6de1dbbd09c12abbec7eb187ffa1afbd47302dfa because it causes a
> compiler crash.
>
> Added:
>
>
> Modified:
>     llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
>     llvm/test/Transforms/InstCombine/minmax-intrinsics.ll
>
> Removed:
>
>
>
> ################################################################################
> diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
> index d6ccf0fcc708..210652e23377 100644
> --- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
> +++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
> @@ -795,60 +795,6 @@ static Instruction *foldClampRangeOfTwo(IntrinsicInst *II,
>    return SelectInst::Create(Cmp, ConstantInt::get(II->getType(), *C0), I1);
>  }
>
> -/// Reduce a sequence of min/max intrinsics with a common operand.
> -static Instruction *factorizeMinMaxTree(IntrinsicInst *II) {
> -  // Match 3 of the same min/max ops. Example: umin(umin(), umin()).
> -  auto *LHS = dyn_cast<IntrinsicInst>(II->getArgOperand(0));
> -  auto *RHS = dyn_cast<IntrinsicInst>(II->getArgOperand(1));
> -  Intrinsic::ID MinMaxID = II->getIntrinsicID();
> -  if (!LHS || !RHS || LHS->getIntrinsicID() != MinMaxID ||
> -      RHS->getIntrinsicID() != MinMaxID ||
> -      (!LHS->hasOneUse() && !RHS->hasOneUse()))
> -    return nullptr;
> -
> -  Value *A = LHS->getArgOperand(0);
> -  Value *B = LHS->getArgOperand(1);
> -  Value *C = RHS->getArgOperand(0);
> -  Value *D = RHS->getArgOperand(1);
> -
> -  // Look for a common operand.
> -  Value *MinMaxOp = nullptr;
> -  Value *ThirdOp = nullptr;
> -  if (LHS->hasOneUse()) {
> -    // If the LHS is only used in this chain and the RHS is used outside of it,
> -    // reuse the RHS min/max because that will eliminate the LHS.
> -    if (D == A || C == A) {
> -      // min(min(a, b), min(c, a)) --> min(min(c, a), b)
> -      // min(min(a, b), min(a, d)) --> min(min(a, d), b)
> -      MinMaxOp = RHS;
> -      ThirdOp = B;
> -    } else if (D == B || C == B) {
> -      // min(min(a, b), min(c, b)) --> min(min(c, b), a)
> -      // min(min(a, b), min(b, d)) --> min(min(b, d), a)
> -      MinMaxOp = RHS;
> -      ThirdOp = A;
> -    }
> -  } else {
> -    assert(RHS->hasOneUse() && "Expected one-use operand");
> -    // Reuse the LHS. This will eliminate the RHS.
> -    if (D == A || D == B) {
> -      // min(min(a, b), min(c, a)) --> min(min(a, b), c)
> -      // min(min(a, b), min(c, b)) --> min(min(a, b), c)
> -      MinMaxOp = LHS;
> -      ThirdOp = C;
> -    } else if (C == A || C == B) {
> -      // min(min(a, b), min(b, d)) --> min(min(a, b), d)
> -      // min(min(a, b), min(c, b)) --> min(min(a, b), d)
> -      MinMaxOp = LHS;
> -      ThirdOp = D;
> -    }
> -  }
> -
> -  Module *Mod = II->getModule();
> -  Function *MinMax = Intrinsic::getDeclaration(Mod, MinMaxID, II->getType());
> -  return CallInst::Create(MinMax, { MinMaxOp, ThirdOp });
> -}
> -
>  /// CallInst simplification. This mostly only handles folding of intrinsic
>  /// instructions. For normal calls, it allows visitCallBase to do the heavy
>  /// lifting.
> @@ -1110,9 +1056,6 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
>          if (Instruction *R = FoldOpIntoSelect(*II, Sel))
>            return R;
>
> -    if (Instruction *NewMinMax = factorizeMinMaxTree(II))
> -      return NewMinMax;
> -
>      break;
>    }
>    case Intrinsic::bswap: {
>
> diff  --git a/llvm/test/Transforms/InstCombine/minmax-intrinsics.ll b/llvm/test/Transforms/InstCombine/minmax-intrinsics.ll
> index 8693526f198c..54e133ded3c9 100644
> --- a/llvm/test/Transforms/InstCombine/minmax-intrinsics.ll
> +++ b/llvm/test/Transforms/InstCombine/minmax-intrinsics.ll
> @@ -907,8 +907,9 @@ define <3 x i1> @umin_ne_zero2(<3 x i8> %a, <3 x i8> %b) {
>
>  define i8 @smax(i8 %x, i8 %y, i8 %z) {
>  ; CHECK-LABEL: @smax(
> -; CHECK-NEXT:    [[M2:%.*]] = call i8 @llvm.smax.i8(i8 [[X:%.*]], i8 [[Z:%.*]])
> -; CHECK-NEXT:    [[M3:%.*]] = call i8 @llvm.smax.i8(i8 [[M2]], i8 [[Y:%.*]])
> +; CHECK-NEXT:    [[M1:%.*]] = call i8 @llvm.smax.i8(i8 [[X:%.*]], i8 [[Y:%.*]])
> +; CHECK-NEXT:    [[M2:%.*]] = call i8 @llvm.smax.i8(i8 [[X]], i8 [[Z:%.*]])
> +; CHECK-NEXT:    [[M3:%.*]] = call i8 @llvm.smax.i8(i8 [[M1]], i8 [[M2]])
>  ; CHECK-NEXT:    ret i8 [[M3]]
>  ;
>    %m1 = call i8 @llvm.smax.i8(i8 %x, i8 %y)
> @@ -919,8 +920,9 @@ define i8 @smax(i8 %x, i8 %y, i8 %z) {
>
>  define <3 x i8> @smin(<3 x i8> %x, <3 x i8> %y, <3 x i8> %z) {
>  ; CHECK-LABEL: @smin(
> -; CHECK-NEXT:    [[M2:%.*]] = call <3 x i8> @llvm.smin.v3i8(<3 x i8> [[X:%.*]], <3 x i8> [[Z:%.*]])
> -; CHECK-NEXT:    [[M3:%.*]] = call <3 x i8> @llvm.smin.v3i8(<3 x i8> [[M2]], <3 x i8> [[Y:%.*]])
> +; CHECK-NEXT:    [[M1:%.*]] = call <3 x i8> @llvm.smin.v3i8(<3 x i8> [[Y:%.*]], <3 x i8> [[X:%.*]])
> +; CHECK-NEXT:    [[M2:%.*]] = call <3 x i8> @llvm.smin.v3i8(<3 x i8> [[X]], <3 x i8> [[Z:%.*]])
> +; CHECK-NEXT:    [[M3:%.*]] = call <3 x i8> @llvm.smin.v3i8(<3 x i8> [[M1]], <3 x i8> [[M2]])
>  ; CHECK-NEXT:    ret <3 x i8> [[M3]]
>  ;
>    %m1 = call <3 x i8> @llvm.smin.v3i8(<3 x i8> %y, <3 x i8> %x)
> @@ -933,7 +935,8 @@ define i8 @umax(i8 %x, i8 %y, i8 %z) {
>  ; CHECK-LABEL: @umax(
>  ; CHECK-NEXT:    [[M1:%.*]] = call i8 @llvm.umax.i8(i8 [[X:%.*]], i8 [[Y:%.*]])
>  ; CHECK-NEXT:    call void @use(i8 [[M1]])
> -; CHECK-NEXT:    [[M3:%.*]] = call i8 @llvm.umax.i8(i8 [[M1]], i8 [[Z:%.*]])
> +; CHECK-NEXT:    [[M2:%.*]] = call i8 @llvm.umax.i8(i8 [[Z:%.*]], i8 [[X]])
> +; CHECK-NEXT:    [[M3:%.*]] = call i8 @llvm.umax.i8(i8 [[M1]], i8 [[M2]])
>  ; CHECK-NEXT:    ret i8 [[M3]]
>  ;
>    %m1 = call i8 @llvm.umax.i8(i8 %x, i8 %y)
> @@ -945,9 +948,10 @@ define i8 @umax(i8 %x, i8 %y, i8 %z) {
>
>  define i8 @umin(i8 %x, i8 %y, i8 %z) {
>  ; CHECK-LABEL: @umin(
> -; CHECK-NEXT:    [[M2:%.*]] = call i8 @llvm.umin.i8(i8 [[Z:%.*]], i8 [[X:%.*]])
> +; CHECK-NEXT:    [[M1:%.*]] = call i8 @llvm.umin.i8(i8 [[Y:%.*]], i8 [[X:%.*]])
> +; CHECK-NEXT:    [[M2:%.*]] = call i8 @llvm.umin.i8(i8 [[Z:%.*]], i8 [[X]])
>  ; CHECK-NEXT:    call void @use(i8 [[M2]])
> -; CHECK-NEXT:    [[M3:%.*]] = call i8 @llvm.umin.i8(i8 [[M2]], i8 [[Y:%.*]])
> +; CHECK-NEXT:    [[M3:%.*]] = call i8 @llvm.umin.i8(i8 [[M1]], i8 [[M2]])
>  ; CHECK-NEXT:    ret i8 [[M3]]
>  ;
>    %m1 = call i8 @llvm.umin.i8(i8 %y, i8 %x)
>
>
>
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