diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp | 20 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/trunc.ll | 10 |
2 files changed, 6 insertions, 24 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp index a1ac64dda35..e60687fa7ad 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -463,23 +463,6 @@ Instruction *InstCombiner::shrinkBitwiseLogic(TruncInst &Trunc) { return BinaryOperator::Create(LogicOp->getOpcode(), NarrowOp0, NarrowC); } -/// Try to narrow the width of a splat shuffle. This could be generalized to any -/// shuffle with a constant operand, but we limit the transform to avoid -/// creating a shuffle type that targets may not be able to lower effectively. -static Instruction *shrinkSplatShuffle(TruncInst &Trunc, - InstCombiner::BuilderTy &Builder) { - auto *Shuf = dyn_cast<ShuffleVectorInst>(Trunc.getOperand(0)); - if (Shuf && Shuf->hasOneUse() && isa<UndefValue>(Shuf->getOperand(1)) && - Shuf->getMask()->getSplatValue()) { - // trunc (shuf X, Undef, SplatMask) --> shuf (trunc X), Undef, SplatMask - Constant *NarrowUndef = UndefValue::get(Trunc.getType()); - Value *NarrowOp = Builder.CreateTrunc(Shuf->getOperand(0), Trunc.getType()); - return new ShuffleVectorInst(NarrowOp, NarrowUndef, Shuf->getMask()); - } - - return nullptr; -} - Instruction *InstCombiner::visitTrunc(TruncInst &CI) { if (Instruction *Result = commonCastTransforms(CI)) return Result; @@ -571,9 +554,6 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) { if (Instruction *I = shrinkBitwiseLogic(CI)) return I; - if (Instruction *I = shrinkSplatShuffle(CI, *Builder)) - return I; - if (Src->hasOneUse() && isa<IntegerType>(SrcTy) && shouldChangeType(SrcTy, DestTy)) { // Transform "trunc (shl X, cst)" -> "shl (trunc X), cst" so long as the diff --git a/llvm/test/Transforms/InstCombine/trunc.ll b/llvm/test/Transforms/InstCombine/trunc.ll index ba72908d3c4..581e990df0f 100644 --- a/llvm/test/Transforms/InstCombine/trunc.ll +++ b/llvm/test/Transforms/InstCombine/trunc.ll @@ -478,12 +478,13 @@ define <4 x i8> @wide_shuf(<4 x i32> %x) { ret <4 x i8> %trunc } +; FIXME: ; trunc (shuffle X, undef, SplatMask) --> shuffle (trunc X), undef, SplatMask define <4 x i8> @wide_splat1(<4 x i32> %x) { ; CHECK-LABEL: @wide_splat1( -; CHECK-NEXT: [[TMP1:%.*]] = trunc <4 x i32> %x to <4 x i8> -; CHECK-NEXT: [[TRUNC:%.*]] = shufflevector <4 x i8> [[TMP1]], <4 x i8> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2> +; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2> +; CHECK-NEXT: [[TRUNC:%.*]] = trunc <4 x i32> [[SHUF]] to <4 x i8> ; CHECK-NEXT: ret <4 x i8> [[TRUNC]] ; %shuf = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> <i32 2, i32 2, i32 2, i32 2> @@ -491,13 +492,14 @@ define <4 x i8> @wide_splat1(<4 x i32> %x) { ret <4 x i8> %trunc } +; FIXME: ; Test weird types. ; trunc (shuffle X, undef, SplatMask) --> shuffle (trunc X), undef, SplatMask define <3 x i31> @wide_splat2(<3 x i33> %x) { ; CHECK-LABEL: @wide_splat2( -; CHECK-NEXT: [[TMP1:%.*]] = trunc <3 x i33> %x to <3 x i31> -; CHECK-NEXT: [[TRUNC:%.*]] = shufflevector <3 x i31> [[TMP1]], <3 x i31> undef, <3 x i32> <i32 1, i32 1, i32 1> +; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <3 x i33> %x, <3 x i33> undef, <3 x i32> <i32 1, i32 1, i32 1> +; CHECK-NEXT: [[TRUNC:%.*]] = trunc <3 x i33> [[SHUF]] to <3 x i31> ; CHECK-NEXT: ret <3 x i31> [[TRUNC]] ; %shuf = shufflevector <3 x i33> %x, <3 x i33> undef, <3 x i32> <i32 1, i32 1, i32 1> |
