From b9ebacdb4dccd0048b7fc8bcd2559d17e5293d38 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sat, 6 May 2006 23:05:41 +0000 Subject: [PATCH] constant fold sign_extend_inreg git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28151 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 4809db47756..60a749df2f7 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -1335,6 +1335,14 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, ConstantSDNode *N1C = dyn_cast(N1.Val); ConstantSDNode *N2C = dyn_cast(N2.Val); if (N1C) { + if (Opcode == ISD::SIGN_EXTEND_INREG) { + int64_t Val = N1C->getValue(); + unsigned FromBits = MVT::getSizeInBits(cast(N2)->getVT()); + Val <<= 64-FromBits; + Val >>= 64-FromBits; + return getConstant(Val, VT); + } + if (N2C) { uint64_t C1 = N1C->getValue(), C2 = N2C->getValue(); switch (Opcode) { @@ -1441,7 +1449,7 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, } } - // Fold a bunch of operators that + // Fold a bunch of operators when the RHS is undef. if (N2.getOpcode() == ISD::UNDEF) { switch (Opcode) { case ISD::ADD: -- 2.34.1