From 05324ab01567f5b7a90f587ec36f54c1bef53c99 Mon Sep 17 00:00:00 2001 From: Manman Ren Date: Fri, 31 Jan 2014 01:10:35 +0000 Subject: This patch teaches the DAGCombiner how to fold insert_subvector nodes when the input is a concat_vectors and the insert replaces one of the concat halves: Lower half: fold (insert_subvector (concat_vectors X, Y), Z) -> (concat_vectors Z, Y) Upper half: fold (insert_subvector (concat_vectors X, Y), Z) -> (concat_vectors X, Z) This can be seen with the following IR: define <8 x float> @lower_half(<4 x float> %v1, <4 x float> %v2, <4 x float> %v3) { %1 = shufflevector <4 x float> %v1, <4 x float> %v2, <8 x i32> %2 = tail call <8 x float> @llvm.x86.avx.vinsertf128.ps.256(<8 x float> %1, <4 x float> %v3, i8 0) The vinsertf128 intrinsic is converted into an insert_subvector node in SelectionDAGBuilder.cpp. Using AVX, without the patch this generates two vinsertf128 instructions: vinsertf128 $1, %xmm1, %ymm0, %ymm0 vinsertf128 $0, %xmm2, %ymm0, %ymm0 With the patch this is optimized into: vinsertf128 $1, %xmm1, %ymm2, %ymm0 Patch by Robert Lougher. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200506 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 29 +++++++++++++++++++++++++++++ test/CodeGen/X86/vec_shuf-insert.ll | 28 ++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) create mode 100644 test/CodeGen/X86/vec_shuf-insert.ll diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 7dd85a8be7..32c07ad4f5 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -274,6 +274,7 @@ namespace { SDValue visitCONCAT_VECTORS(SDNode *N); SDValue visitEXTRACT_SUBVECTOR(SDNode *N); SDValue visitVECTOR_SHUFFLE(SDNode *N); + SDValue visitINSERT_SUBVECTOR(SDNode *N); SDValue XformToShuffleWithZero(SDNode *N); SDValue ReassociateOps(unsigned Opc, SDLoc DL, SDValue LHS, SDValue RHS); @@ -1230,6 +1231,7 @@ SDValue DAGCombiner::visit(SDNode *N) { case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N); case ISD::EXTRACT_SUBVECTOR: return visitEXTRACT_SUBVECTOR(N); case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); + case ISD::INSERT_SUBVECTOR: return visitINSERT_SUBVECTOR(N); } return SDValue(); } @@ -10433,6 +10435,33 @@ SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { return SDValue(); } +SDValue DAGCombiner::visitINSERT_SUBVECTOR(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N2 = N->getOperand(2); + + // If the input vector is a concatenation, and the insert replaces + // one of the halves, we can optimize into a single concat_vectors. + if (N0.getOpcode() == ISD::CONCAT_VECTORS && + N0->getNumOperands() == 2 && N2.getOpcode() == ISD::Constant) { + APInt InsIdx = cast(N2)->getAPIntValue(); + EVT VT = N->getValueType(0); + + // Lower half: fold (insert_subvector (concat_vectors X, Y), Z) -> + // (concat_vectors Z, Y) + if (InsIdx == 0) + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, + N->getOperand(1), N0.getOperand(1)); + + // Upper half: fold (insert_subvector (concat_vectors X, Y), Z) -> + // (concat_vectors X, Z) + if (InsIdx == VT.getVectorNumElements()/2) + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, + N0.getOperand(0), N->getOperand(1)); + } + + return SDValue(); +} + /// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform /// an AND to a vector_shuffle with the destination vector and a zero vector. /// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==> diff --git a/test/CodeGen/X86/vec_shuf-insert.ll b/test/CodeGen/X86/vec_shuf-insert.ll new file mode 100644 index 0000000000..254fdbc15b --- /dev/null +++ b/test/CodeGen/X86/vec_shuf-insert.ll @@ -0,0 +1,28 @@ +; RUN: llc < %s -mtriple=x86_64-unknown-linux -mcpu=corei7-avx | FileCheck %s + +; These tests check that an insert_subvector which replaces one of the halves +; of a concat_vectors is optimized into a single vinsertf128. + +declare <8 x float> @llvm.x86.avx.vinsertf128.ps.256(<8 x float>, <4 x float>, i8) + +define <8 x float> @lower_half(<4 x float> %v1, <4 x float> %v2, <4 x float> %v3) { + %1 = shufflevector <4 x float> %v1, <4 x float> %v2, <8 x i32> + %2 = tail call <8 x float> @llvm.x86.avx.vinsertf128.ps.256(<8 x float> %1, <4 x float> %v3, i8 0) + ret <8 x float> %2 + +; CHECK-LABEL: lower_half +; CHECK-NOT: vinsertf128 +; CHECK: vinsertf128 $1, %xmm1, %ymm2, %ymm0 +; CHECK-NEXT: ret +} + +define <8 x float> @upper_half(<4 x float> %v1, <4 x float> %v2, <4 x float> %v3) { + %1 = shufflevector <4 x float> %v1, <4 x float> %v2, <8 x i32> + %2 = tail call <8 x float> @llvm.x86.avx.vinsertf128.ps.256(<8 x float> %1, <4 x float> %v3, i8 1) + ret <8 x float> %2 + +; CHECK-LABEL: upper_half +; CHECK-NOT: vinsertf128 +; CHECK: vinsertf128 $1, %xmm2, %ymm0, %ymm0 +; CHECK-NEXT: ret +} -- cgit v1.2.3