Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp =================================================================== --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -12240,6 +12240,14 @@ // converts. } + // extract_vector_elt (v2i32 (bitcast i64:x)), 0 -> i32 (trunc i64:x) + if (ConstEltNo && InVec.getOpcode() == ISD::BITCAST && InVec.hasOneUse() && + ConstEltNo->isNullValue()) { + SDValue BCSrc = InVec.getOperand(0); + if (BCSrc.getValueType().isScalarInteger()) + return DAG.getNode(ISD::TRUNCATE, SDLoc(InVec), NVT, BCSrc); + } + // Transform: (EXTRACT_VECTOR_ELT( VECTOR_SHUFFLE )) -> EXTRACT_VECTOR_ELT. // We only perform this optimization before the op legalization phase because // we may introduce new vector instructions which are not backed by TD Index: lib/Target/X86/X86ISelLowering.cpp =================================================================== --- lib/Target/X86/X86ISelLowering.cpp +++ lib/Target/X86/X86ISelLowering.cpp @@ -24697,13 +24697,7 @@ if (InputVector.getOpcode() == ISD::BITCAST && InputVector.hasOneUse() && N->getValueType(0) == MVT::i32 && InputVector.getValueType() == MVT::v2i32) { - - // The bitcast source is a direct mmx result. SDValue MMXSrc = InputVector.getNode()->getOperand(0); - if (MMXSrc.getValueType() == MVT::x86mmx) - return DAG.getNode(X86ISD::MMX_MOVD2W, SDLoc(InputVector), - N->getValueType(0), - InputVector.getNode()->getOperand(0)); // The mmx is indirect: (i64 extract_elt (v1i64 bitcast (x86mmx ...))). if (MMXSrc.getOpcode() == ISD::EXTRACT_VECTOR_ELT && MMXSrc.hasOneUse() && @@ -27750,11 +27744,22 @@ static SDValue PerformTRUNCATECombine(SDNode *N, SelectionDAG &DAG, const X86Subtarget &Subtarget) { + + SDValue Src = N->getOperand(0); + // Try to detect AVG pattern first. - if (SDValue Avg = detectAVGPattern(N->getOperand(0), N->getValueType(0), DAG, + if (SDValue Avg = detectAVGPattern(Src, N->getValueType(0), DAG, Subtarget, SDLoc(N))) return Avg; + // The bitcast source is a direct mmx result. + // Detect bitcasts between i32 to x86mmx + if (Src.getOpcode() == ISD::BITCAST && N->getValueType(0) == MVT::i32) { + SDValue BCSrc = Src.getOperand(0); + if (BCSrc.getValueType() == MVT::x86mmx) + return DAG.getNode(X86ISD::MMX_MOVD2W, SDLoc(N), MVT::i32, BCSrc); + } + return combineVectorTruncation(N, DAG, Subtarget); } Index: test/CodeGen/AMDGPU/extractelt-to-trunc.ll =================================================================== --- /dev/null +++ test/CodeGen/AMDGPU/extractelt-to-trunc.ll @@ -0,0 +1,17 @@ +; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s + +; Make sure the add and load are reduced to 32-bits even with the +; bitcast to vector. +; GCN-LABEL: {{^}}bitcast_int_to_vector_extract_0: +; GCN-DAG: s_load_dword [[B:s[0-9]+]] +; GCN-DAG: buffer_load_dword [[A:v[0-9]+]] +; GCN: v_add_i32_e32 [[ADD:v[0-9]+]], vcc, [[B]], [[A]] +; GCN: buffer_store_dword [[ADD]] +define void @bitcast_int_to_vector_extract_0(i32 addrspace(1)* %out, i64 addrspace(1)* %in, i64 %b) { + %a = load i64, i64 addrspace(1)* %in + %add = add i64 %a, %b + %val.bc = bitcast i64 %add to <2 x i32> + %extract = extractelement <2 x i32> %val.bc, i32 0 + store i32 %extract, i32 addrspace(1)* %out + ret void +}