[ConstantFolding] Add folding for [de]interleave2, insert and extract

llvm/lib/Analysis/ConstantFolding.cpp

@@ -1619,6 +1619,10 @@ bool llvm::canConstantFoldCallTo(const CallBase *Call, const Function *F) {
   case Intrinsic::vector_reduce_smax:
   case Intrinsic::vector_reduce_umin:
   case Intrinsic::vector_reduce_umax:
+  case Intrinsic::vector_extract:
+  case Intrinsic::vector_insert:
+  case Intrinsic::vector_interleave2:
+  case Intrinsic::vector_deinterleave2:
   // Target intrinsics
   case Intrinsic::amdgcn_perm:
   case Intrinsic::amdgcn_wave_reduce_umin:
@@ -3734,6 +3738,98 @@ static Constant *ConstantFoldFixedVectorCall(
     }
     return nullptr;
   }
+  case Intrinsic::vector_extract: {
+    auto *Vec = dyn_cast<Constant>(Operands[0]);
+    auto *Idx = cast<ConstantInt>(Operands[1]);
+    if (!Vec || !Idx || !isa<FixedVectorType>(Vec->getType()))
+      return nullptr;
+
+    unsigned NumElements = FVTy->getNumElements();
+    unsigned VecNumElements =
+        cast<FixedVectorType>(Vec->getType())->getNumElements();
+    unsigned StartingIndex = Idx->getZExtValue();
+
+    // Extracting entire vector is nop
+    if (NumElements == VecNumElements && StartingIndex == 0)
+      return Vec;
+
+    const unsigned NonPoisonNumElements =
+        std::min(StartingIndex + NumElements, VecNumElements);
+    for (unsigned I = StartingIndex; I < NonPoisonNumElements; ++I) {
+      Constant *Elt = Vec->getAggregateElement(I);
+      if (!Elt)
+        return nullptr;
+      Result[I - StartingIndex] = Elt;
+    }
+
+    // Remaining elements are poison since they are out of bounds.
+    for (unsigned I = NonPoisonNumElements, E = StartingIndex + NumElements;
+         I < E; ++I)
+      Result[I - StartingIndex] = PoisonValue::get(FVTy->getElementType());
+
+    return ConstantVector::get(Result);
+  }
+  case Intrinsic::vector_insert: {
+    auto *Vec = dyn_cast<Constant>(Operands[0]);
+    auto *SubVec = dyn_cast<Constant>(Operands[1]);
+    auto *Idx = dyn_cast<ConstantInt>(Operands[2]);
+    if (!Vec || !SubVec || !Idx || !isa<FixedVectorType>(Vec->getType()))
+      return nullptr;
+
+    unsigned SubVecNumElements =
+        cast<FixedVectorType>(SubVec->getType())->getNumElements();
+    unsigned VecNumElements =
+        cast<FixedVectorType>(Vec->getType())->getNumElements();
+    unsigned IdxN = Idx->getZExtValue();
+    // Replacing entire vector with a subvec is nop
+    if (SubVecNumElements == VecNumElements && IdxN == 0)
+      return SubVec;
+
+    // Make sure indices are in the range [0, VecNumElements), otherwise the
+    // result is a poison value.
+    if (IdxN >= VecNumElements || IdxN + SubVecNumElements > VecNumElements ||
+        (IdxN && (SubVecNumElements % IdxN) != 0))
+      return PoisonValue::get(FVTy);
+
+    unsigned I = 0;
+    for (; I < IdxN; ++I) {
+      Constant *Elt = Vec->getAggregateElement(I);
+      if (!Elt)
+        return nullptr;
+      Result[I] = Elt;
+    }
+    for (; I < IdxN + SubVecNumElements; ++I) {
+      Constant *Elt = SubVec->getAggregateElement(I - IdxN);
+      if (!Elt)
+        return nullptr;
+      Result[I] = Elt;
+    }
+    for (; I < VecNumElements; ++I) {
+      Constant *Elt = Vec->getAggregateElement(I);
+      if (!Elt)
+        return nullptr;
+      Result[I] = Elt;
+    }
+    return ConstantVector::get(Result);
+  }
+  case Intrinsic::vector_interleave2: {
+    auto *Vec0 = dyn_cast<Constant>(Operands[0]);
+    auto *Vec1 = dyn_cast<Constant>(Operands[1]);
+    if (!Vec0 || !Vec1)
+      return nullptr;
+
+    unsigned NumElements =
+        cast<FixedVectorType>(Vec0->getType())->getNumElements();
+    for (unsigned I = 0; I < NumElements; ++I) {
+      Constant *Elt0 = Vec0->getAggregateElement(I);
+      Constant *Elt1 = Vec1->getAggregateElement(I);
+      if (!Elt0 || !Elt1)
+        return nullptr;
+      Result[2 * I] = Elt0;
+      Result[2 * I + 1] = Elt1;
+    }
+    return ConstantVector::get(Result);
+  }
   default:
     break;
   }
@@ -3872,6 +3968,26 @@ ConstantFoldStructCall(StringRef Name, Intrinsic::ID IntrinsicID,
       return nullptr;
     return ConstantStruct::get(StTy, SinResult, CosResult);
   }
+  case Intrinsic::vector_deinterleave2: {
+    auto *Vec = dyn_cast<Constant>(Operands[0]);
+    if (!Vec)
+      return nullptr;
+
+    unsigned NumElements =
+        cast<VectorType>(Vec->getType())->getElementCount().getKnownMinValue() /
+        2;
+    SmallVector<Constant *, 4> Res0(NumElements), Res1(NumElements);
+    for (unsigned I = 0; I < NumElements; ++I) {
+      Constant *Elt0 = Vec->getAggregateElement(2 * I);
+      Constant *Elt1 = Vec->getAggregateElement(2 * I + 1);
+      if (!Elt0 || !Elt1)
+        return nullptr;
+      Res0[I] = Elt0;
+      Res1[I] = Elt1;
+    }
+    return ConstantStruct::get(StTy, ConstantVector::get(Res0),
+                               ConstantVector::get(Res1));
+  }
   default:
     // TODO: Constant folding of vector intrinsics that fall through here does
     // not work (e.g. overflow intrinsics)

llvm/test/Transforms/InstSimplify/ConstProp/vector-calls.ll

@@ -0,0 +1,100 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -passes=instsimplify,verify -disable-verify -S | FileCheck %s
+
+define <3 x i32> @fold_vector_extract() {
+; CHECK-LABEL: define <3 x i32> @fold_vector_extract() {
+; CHECK-NEXT:    ret <3 x i32> <i32 3, i32 4, i32 5>
+;
+  %1 = call <3 x i32> @llvm.vector.extract.v3i32.v8i32(<8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>, i64 3)
+  ret <3 x i32> %1
+}
+
+@a = external global i16, align 1
+
+define <3 x i32> @fold_vector_extract_constexpr() {
+; CHECK-LABEL: define <3 x i32> @fold_vector_extract_constexpr() {
+; CHECK-NEXT:    ret <3 x i32> <i32 ptrtoint (ptr @a to i32), i32 1, i32 2>
+;
+  %1 = call <3 x i32> @llvm.vector.extract.v3i32.v8i32(<8 x i32> <i32 ptrtoint (ptr @a to i32), i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>, i64 0)
+  ret <3 x i32> %1
+}
+
+define <3 x i32> @fold_vector_extract_last_poison() {
+; CHECK-LABEL: define <3 x i32> @fold_vector_extract_last_poison() {
+; CHECK-NEXT:    ret <3 x i32> <i32 6, i32 7, i32 poison>
+;
+  %1 = call <3 x i32> @llvm.vector.extract.v3i32.v8i32(<8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>, i64 6)
+  ret <3 x i32> %1
+}
+
+define <3 x i32> @fold_vector_extract_poison() {
+; CHECK-LABEL: define <3 x i32> @fold_vector_extract_poison() {
+; CHECK-NEXT:    ret <3 x i32> poison
+;
+  %1 = call <3 x i32> @llvm.vector.extract.v3i32.v8i32(<8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>, i64 8)
+  ret <3 x i32> %1
+}
+
+define <8 x i32> @fold_vector_extract_nop() {
+; CHECK-LABEL: define <8 x i32> @fold_vector_extract_nop() {
+; CHECK-NEXT:    ret <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+;
+  %1 = call <8 x i32> @llvm.vector.extract.v3i32.v8i32(<8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>, i64 0)
+  ret <8 x i32> %1
+}
+
+define <8 x i32> @fold_vector_insert() {
+; CHECK-LABEL: define <8 x i32> @fold_vector_insert() {
+; CHECK-NEXT:    ret <8 x i32> <i32 9, i32 10, i32 11, i32 12, i32 5, i32 6, i32 7, i32 8>
+;
+  %1 = call <8 x i32> @llvm.vector.insert.v8i32(<8 x i32> <i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8>, <4 x i32> <i32 9, i32 10, i32 11, i32 12>, i64 0)
+  ret <8 x i32> %1
+}
+
+define <8 x i32> @fold_vector_insert_nop() {
+; CHECK-LABEL: define <8 x i32> @fold_vector_insert_nop() {
+; CHECK-NEXT:    ret <8 x i32> <i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18>
+;
+  %1 = call <8 x i32> @llvm.vector.insert.v8i32(<8 x i32> <i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8>, <8 x i32> <i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18>, i64 0)
+  ret <8 x i32> %1
+}
+
+define <8 x i32> @fold_vector_insert_poison_idx_range() {
+; CHECK-LABEL: define <8 x i32> @fold_vector_insert_poison_idx_range() {
+; CHECK-NEXT:    ret <8 x i32> poison
+;
+  %1 = call <8 x i32> @llvm.vector.insert.v8i32(<8 x i32> <i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8>, <6 x i32> <i32 9, i32 10, i32 11, i32 12, i32 13, i32 14>, i64 6)
+  ret <8 x i32> %1
+}
+
+define <8 x i32> @fold_vector_insert_poison_large_idx() {
+; CHECK-LABEL: define <8 x i32> @fold_vector_insert_poison_large_idx() {
+; CHECK-NEXT:    ret <8 x i32> poison
+;
+  %1 = call <8 x i32> @llvm.vector.insert.v8i32(<8 x i32> <i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8>, <6 x i32> <i32 9, i32 10, i32 11, i32 12, i32 13, i32 14>, i64 -2)
+  ret <8 x i32> %1
+}
+
+define <8 x i32> @fold_vector_interleave2() {
+; CHECK-LABEL: define <8 x i32> @fold_vector_interleave2() {
+; CHECK-NEXT:    ret <8 x i32> <i32 1, i32 5, i32 2, i32 6, i32 3, i32 7, i32 4, i32 8>
+;
+  %1 = call<8 x i32> @llvm.vector.interleave2.v8i32(<4 x i32> <i32 1, i32 2, i32 3, i32 4>, <4 x i32> <i32 5, i32 6, i32 7, i32 8>)
+  ret <8 x i32> %1
+}
+
+define {<4 x i32>, <4 x i32>} @fold_vector_deinterleav2() {
+; CHECK-LABEL: define { <4 x i32>, <4 x i32> } @fold_vector_deinterleav2() {
+; CHECK-NEXT:    ret { <4 x i32>, <4 x i32> } { <4 x i32> <i32 1, i32 2, i32 3, i32 4>, <4 x i32> <i32 5, i32 6, i32 7, i32 8> }
+;
+  %1 = call {<4 x i32>, <4 x i32>} @llvm.vector.deinterleave2.v4i32.v8i32(<8 x i32> <i32 1, i32 5, i32 2, i32 6, i32 3, i32 7, i32 4, i32 8>)
+  ret {<4 x i32>, <4 x i32>} %1
+}
+
+define {<vscale x 4 x i32>, <vscale x 4 x i32>} @fold_scalable_vector_deinterleav2() {
+; CHECK-LABEL: define { <vscale x 4 x i32>, <vscale x 4 x i32> } @fold_scalable_vector_deinterleav2() {
+; CHECK-NEXT:    ret { <vscale x 4 x i32>, <vscale x 4 x i32> } zeroinitializer
+;
+  %1 = call {<vscale x 4 x i32>, <vscale x 4 x i32>} @llvm.vector.deinterleave2.v4i32.v8i32(<vscale x 8 x i32> zeroinitializer)
+  ret {<vscale x 4 x i32>, <vscale x 4 x i32>} %1
+}