diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstructionCombining.cpp | 18 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/vec_shuffle.ll | 16 |
2 files changed, 22 insertions, 12 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp index 99d3d478aaf..99874b31912 100644 --- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -1393,7 +1393,10 @@ Instruction *InstCombiner::foldShuffledBinop(BinaryOperator &Inst) { if (match(&Inst, m_c_BinOp( m_OneUse(m_ShuffleVector(m_Value(V1), m_Undef(), m_Constant(Mask))), m_Constant(C))) && - V1->getType() == Inst.getType()) { + V1->getType()->getVectorNumElements() <= VWidth) { + assert(Inst.getType()->getScalarType() == V1->getType()->getScalarType() && + "Shuffle should not change scalar type"); + unsigned V1Width = V1->getType()->getVectorNumElements(); // Find constant NewC that has property: // shuffle(NewC, ShMask) = C // If such constant does not exist (example: ShMask=<0,0> and C=<1,2>) @@ -1402,14 +1405,21 @@ Instruction *InstCombiner::foldShuffledBinop(BinaryOperator &Inst) { SmallVector<int, 16> ShMask; ShuffleVectorInst::getShuffleMask(Mask, ShMask); SmallVector<Constant *, 16> - NewVecC(VWidth, UndefValue::get(C->getType()->getScalarType())); + NewVecC(V1Width, UndefValue::get(C->getType()->getScalarType())); bool MayChange = true; for (unsigned I = 0; I < VWidth; ++I) { if (ShMask[I] >= 0) { - assert(ShMask[I] < (int)VWidth); + assert(ShMask[I] < (int)VWidth && "Not expecting narrowing shuffle"); Constant *CElt = C->getAggregateElement(I); Constant *NewCElt = NewVecC[ShMask[I]]; - if (!CElt || (!isa<UndefValue>(NewCElt) && NewCElt != CElt)) { + // Bail out if: + // 1. The constant vector contains a constant expression. + // 2. The shuffle needs an element of the constant vector that can't + // be mapped to a new constant vector. + // 3. This is a widening shuffle that copies elements of V1 into the + // extended elements (extending with undef is allowed). + if (!CElt || (!isa<UndefValue>(NewCElt) && NewCElt != CElt) || + I >= V1Width) { MayChange = false; break; } diff --git a/llvm/test/Transforms/InstCombine/vec_shuffle.ll b/llvm/test/Transforms/InstCombine/vec_shuffle.ll index 17aad9325bb..cf09427557e 100644 --- a/llvm/test/Transforms/InstCombine/vec_shuffle.ll +++ b/llvm/test/Transforms/InstCombine/vec_shuffle.ll @@ -474,12 +474,12 @@ define <2 x float> @fmul_const_invalid_constant(<2 x float> %v) { ret <2 x float> %r } -; TODO: Reduce the width of the binop by moving it ahead of a shuffle. +; Reduce the width of the binop by moving it ahead of a shuffle. define <4 x i8> @widening_shuffle_add_1(<2 x i8> %x) { ; CHECK-LABEL: @widening_shuffle_add_1( -; CHECK-NEXT: [[WIDEX:%.*]] = shufflevector <2 x i8> [[X:%.*]], <2 x i8> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef> -; CHECK-NEXT: [[R:%.*]] = add <4 x i8> [[WIDEX]], <i8 42, i8 43, i8 44, i8 45> +; CHECK-NEXT: [[TMP1:%.*]] = add <2 x i8> [[X:%.*]], <i8 42, i8 43> +; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i8> [[TMP1]], <2 x i8> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef> ; CHECK-NEXT: ret <4 x i8> [[R]] ; %widex = shufflevector <2 x i8> %x, <2 x i8> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef> @@ -487,12 +487,12 @@ define <4 x i8> @widening_shuffle_add_1(<2 x i8> %x) { ret <4 x i8> %r } -; TODO: Reduce the width of the binop by moving it ahead of a shuffle. +; Reduce the width of the binop by moving it ahead of a shuffle. define <4 x i8> @widening_shuffle_add_2(<2 x i8> %x) { ; CHECK-LABEL: @widening_shuffle_add_2( -; CHECK-NEXT: [[WIDEX:%.*]] = shufflevector <2 x i8> [[X:%.*]], <2 x i8> undef, <4 x i32> <i32 1, i32 0, i32 undef, i32 undef> -; CHECK-NEXT: [[R:%.*]] = add <4 x i8> [[WIDEX]], <i8 42, i8 43, i8 44, i8 45> +; CHECK-NEXT: [[TMP1:%.*]] = add <2 x i8> [[X:%.*]], <i8 43, i8 42> +; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i8> [[TMP1]], <2 x i8> undef, <4 x i32> <i32 1, i32 0, i32 undef, i32 undef> ; CHECK-NEXT: ret <4 x i8> [[R]] ; %widex = shufflevector <2 x i8> %x, <2 x i8> undef, <4 x i32> <i32 1, i32 0, i32 undef, i32 undef> @@ -500,7 +500,7 @@ define <4 x i8> @widening_shuffle_add_2(<2 x i8> %x) { ret <4 x i8> %r } -; Widening shuffles have the same mask/constant constraint as non-size-changing shuffles. +; Negative test - widening shuffles have the same mask/constant constraint as non-size-changing shuffles. define <4 x i8> @widening_shuffle_add_invalid_constant(<2 x i8> %x) { ; CHECK-LABEL: @widening_shuffle_add_invalid_constant( @@ -513,7 +513,7 @@ define <4 x i8> @widening_shuffle_add_invalid_constant(<2 x i8> %x) { ret <4 x i8> %r } -; And widening shuffles have an additional constraint - they must not extend with anything but undefs. +; Negative test - widening shuffles have an additional constraint: they must not extend with anything but undefs. define <4 x i8> @widening_shuffle_add_invalid_mask(<2 x i8> %x) { ; CHECK-LABEL: @widening_shuffle_add_invalid_mask( |
