Index: lib/CodeGen/SelectionDAG/LegalizeTypes.cpp =================================================================== --- lib/CodeGen/SelectionDAG/LegalizeTypes.cpp +++ lib/CodeGen/SelectionDAG/LegalizeTypes.cpp @@ -1007,6 +1007,8 @@ // Calculate the element offset and add it to the pointer. unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size. + assert(EltSize * 8 == EltVT.getSizeInBits() && + "Converting bits to bytes lost precision"); Index = DAG.getNode(ISD::MUL, dl, Index.getValueType(), Index, DAG.getConstant(EltSize, dl, Index.getValueType())); Index: lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp =================================================================== --- lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp +++ lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp @@ -1554,9 +1554,25 @@ if (CustomLowerNode(N, N->getValueType(0), true)) return SDValue(); - // Store the vector to the stack. - EVT EltVT = VecVT.getVectorElementType(); + // Make the vector elements byte-addressable if they aren't already. SDLoc dl(N); + EVT EltVT = VecVT.getVectorElementType(); + if (EltVT.getSizeInBits() < 8) { + SmallVector ElementOps; + for (unsigned i = 0; i < VecVT.getVectorNumElements(); ++i) { + ElementOps.push_back(DAG.getAnyExtOrTrunc( + DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, EltVT, Vec, + DAG.getConstant(i, dl, MVT::i8)), + dl, MVT::i8)); + } + + EltVT = MVT::i8; + VecVT = EVT::getVectorVT(*DAG.getContext(), EltVT, + VecVT.getVectorNumElements()); + Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, VecVT, ElementOps); + } + + // Store the vector to the stack. SDValue StackPtr = DAG.CreateStackTemporary(VecVT); SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Vec, StackPtr, MachinePointerInfo(), false, false, 0); Index: test/CodeGen/Mips/llvm-ir/extractelement.ll =================================================================== --- /dev/null +++ test/CodeGen/Mips/llvm-ir/extractelement.ll @@ -0,0 +1,19 @@ +; RUN: llc < %s -march=mips -mcpu=mips2 | FileCheck %s -check-prefix=ALL + +; This test triggered a bug in the vector splitting where the type legalizer +; attempted to extract the element with by storing the vector, then reading +; an element back. However, the address calculation was: +; Base + Index * (EltSizeInBits / 8) +; and EltSizeInBits was 1. This caused the index to be forgotten. +define i1 @via_stack_bug(i8 signext %idx) { + %1 = extractelement <2 x i1> , i8 %idx + ret i1 %1 +} + +; ALL-LABEL: via_stack_bug: +; ALL-DAG: addiu [[ONE:\$[0-9]+]], $zero, 1 +; ALL-DAG: sb [[ONE]], 7($sp) +; ALL-DAG: sb $zero, 6($sp) +; ALL-DAG: addiu [[VPTR:\$[0-9]+]], $sp, 6 +; ALL-DAG: addu [[EPTR:\$[0-9]+]], $4, [[VPTR]] +; ALL: lbu $2, 0([[EPTR]])