From 863ac769b850d75a390bfdc20b62d7d120fb69a9 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 19 Sep 2006 05:02:39 +0000 Subject: [PATCH] Fold extract_element(cst) to cst git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30478 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 55b128f515d..c310ac7faea 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -1330,12 +1330,18 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, break; } case ISD::EXTRACT_ELEMENT: + assert(N2C && (unsigned)N2C->getValue() < 2 && "Bad EXTRACT_ELEMENT!"); + // EXTRACT_ELEMENT of BUILD_PAIR is often formed while legalize is expanding // 64-bit integers into 32-bit parts. Instead of building the extract of // the BUILD_PAIR, only to have legalize rip it apart, just do it now. - if (N2C && N1.getOpcode() == ISD::BUILD_PAIR) { - assert((unsigned)N2C->getValue() < 2 && "Bad EXTRACT_ELEMENT!"); + if (N1.getOpcode() == ISD::BUILD_PAIR) return N1.getOperand(N2C->getValue()); + + // EXTRACT_ELEMENT of a constant int is also very common. + if (ConstantSDNode *C = dyn_cast(N1)) { + unsigned Shift = MVT::getSizeInBits(VT) * N2C->getValue(); + return getConstant(C->getValue() >> Shift, VT); } break; -- 2.34.1