diff options
| -rw-r--r-- | llvm/include/llvm/IR/Instructions.h | 12 | ||||
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp | 3 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/vec_shuffle.ll | 25 |
3 files changed, 28 insertions, 12 deletions
diff --git a/llvm/include/llvm/IR/Instructions.h b/llvm/include/llvm/IR/Instructions.h index 54730208476..476c412fd52 100644 --- a/llvm/include/llvm/IR/Instructions.h +++ b/llvm/include/llvm/IR/Instructions.h @@ -2457,13 +2457,23 @@ public: /// Return true if this shuffle returns a vector with a different number of /// elements than its source vectors. - /// Example: shufflevector <4 x n> A, <4 x n> B, <1,2> + /// Examples: shufflevector <4 x n> A, <4 x n> B, <1,2,3> + /// shufflevector <4 x n> A, <4 x n> B, <1,2,3,4,5> bool changesLength() const { unsigned NumSourceElts = Op<0>()->getType()->getVectorNumElements(); unsigned NumMaskElts = getMask()->getType()->getVectorNumElements(); return NumSourceElts != NumMaskElts; } + /// Return true if this shuffle returns a vector with a greater number of + /// elements than its source vectors. + /// Example: shufflevector <2 x n> A, <2 x n> B, <1,2,3> + bool increasesLength() const { + unsigned NumSourceElts = Op<0>()->getType()->getVectorNumElements(); + unsigned NumMaskElts = getMask()->getType()->getVectorNumElements(); + return NumSourceElts < NumMaskElts; + } + /// Return true if this shuffle mask chooses elements from exactly one source /// vector. /// Example: <7,5,undef,7> diff --git a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp index f6c6bab73a0..5dea7de6f05 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineVectorOps.cpp @@ -1464,7 +1464,8 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) { if (isRHSID) return replaceInstUsesWith(SVI, RHS); } - if (isa<UndefValue>(RHS) && CanEvaluateShuffled(LHS, Mask)) { + if (isa<UndefValue>(RHS) && !SVI.increasesLength() && + CanEvaluateShuffled(LHS, Mask)) { Value *V = EvaluateInDifferentElementOrder(LHS, Mask); return replaceInstUsesWith(SVI, V); } diff --git a/llvm/test/Transforms/InstCombine/vec_shuffle.ll b/llvm/test/Transforms/InstCombine/vec_shuffle.ll index 352be09a28a..ce323a40eb2 100644 --- a/llvm/test/Transforms/InstCombine/vec_shuffle.ll +++ b/llvm/test/Transforms/InstCombine/vec_shuffle.ll @@ -184,14 +184,15 @@ define <2 x i8> @test13a(i8 %x1, i8 %x2) { ret <2 x i8> %D } -; TODO: Increasing length of vector ops is not a good canonicalization. - +; Increasing length of vector ops is not a good canonicalization. + define <3 x i32> @add_wider(i32 %y, i32 %z) { -; CHECK-LABEL: @add( -; CHECK-NEXT: [[TMP1:%.*]] = insertelement <3 x i32> undef, i32 [[Y:%.*]], i32 0 -; CHECK-NEXT: [[TMP2:%.*]] = insertelement <3 x i32> [[TMP1]], i32 [[Z:%.*]], i32 1 -; CHECK-NEXT: [[TMP3:%.*]] = add <3 x i32> [[TMP2]], <i32 255, i32 255, i32 undef> -; CHECK-NEXT: ret <3 x i32> [[TMP3]] +; CHECK-LABEL: @add_wider( +; CHECK-NEXT: [[I0:%.*]] = insertelement <2 x i32> undef, i32 [[Y:%.*]], i32 0 +; CHECK-NEXT: [[I1:%.*]] = insertelement <2 x i32> [[I0]], i32 [[Z:%.*]], i32 1 +; CHECK-NEXT: [[A:%.*]] = add <2 x i32> [[I1]], <i32 255, i32 255> +; CHECK-NEXT: [[EXT:%.*]] = shufflevector <2 x i32> [[A]], <2 x i32> undef, <3 x i32> <i32 0, i32 1, i32 undef> +; CHECK-NEXT: ret <3 x i32> [[EXT]] ; %i0 = insertelement <2 x i32> undef, i32 %y, i32 0 %i1 = insertelement <2 x i32> %i0, i32 %z, i32 1 @@ -200,11 +201,15 @@ define <3 x i32> @add_wider(i32 %y, i32 %z) { ret <3 x i32> %ext } -; FIXME: Increasing length of vector ops must be safe from illegal undef propagation. +; Increasing length of vector ops must be safe from illegal undef propagation. define <3 x i32> @div_wider(i32 %y, i32 %z) { -; CHECK-LABEL: @div( -; CHECK-NEXT: ret <3 x i32> undef +; CHECK-LABEL: @div_wider( +; CHECK-NEXT: [[I0:%.*]] = insertelement <2 x i32> undef, i32 [[Y:%.*]], i32 0 +; CHECK-NEXT: [[I1:%.*]] = insertelement <2 x i32> [[I0]], i32 [[Z:%.*]], i32 1 +; CHECK-NEXT: [[A:%.*]] = sdiv <2 x i32> [[I1]], <i32 255, i32 255> +; CHECK-NEXT: [[EXT:%.*]] = shufflevector <2 x i32> [[A]], <2 x i32> undef, <3 x i32> <i32 0, i32 1, i32 undef> +; CHECK-NEXT: ret <3 x i32> [[EXT]] ; %i0 = insertelement <2 x i32> undef, i32 %y, i32 0 %i1 = insertelement <2 x i32> %i0, i32 %z, i32 1 |
