From fd8c39b77331fbb6f994665b45eba1b2cc6ced6d Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Fri, 7 Jan 2005 21:56:24 +0000 Subject: [PATCH] Simplify: truncate ({zero|sign}_extend (X)) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19353 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 3fdc7fe995f..25ec8ff0529 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -428,6 +428,15 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT, if (Operand.getValueType() == VT) return Operand; // noop truncate if (OpOpcode == ISD::TRUNCATE) return getNode(ISD::TRUNCATE, VT, Operand.Val->getOperand(0)); + else if (OpOpcode == ISD::ZERO_EXTEND || OpOpcode == ISD::SIGN_EXTEND) { + // If the source is smaller than the dest, we still need an extend. + if (Operand.Val->getOperand(0).getValueType() < VT) + return getNode(OpOpcode, VT, Operand.Val->getOperand(0)); + else if (Operand.Val->getOperand(0).getValueType() > VT) + return getNode(ISD::TRUNCATE, VT, Operand.Val->getOperand(0)); + else + return Operand.Val->getOperand(0); + } break; }