From c56a81dff1553536efee17445ef5eab276f22380 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 11 Apr 2007 06:43:25 +0000 Subject: [PATCH] don't create shifts by zero, fix some problems with my previous patch git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35887 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index eb63647b436..2c9d41cc577 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2136,7 +2136,7 @@ SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) { SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), DAG.getConstant(~0ULL, VT), DAG.getConstant(0, VT), cast(N0.getOperand(2))->get()); - if (SCC.Val) return SCC; + if (SCC.Val && SCC.Val != N) return SCC; } return SDOperand(); @@ -2226,7 +2226,7 @@ SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) { SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), DAG.getConstant(1, VT), DAG.getConstant(0, VT), cast(N0.getOperand(2))->get()); - if (SCC.Val) return SCC; + if (SCC.Val && SCC.Val != N) return SCC; } return SDOperand(); @@ -2320,7 +2320,8 @@ SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) { SimplifySelectCC(N0.getOperand(0), N0.getOperand(1), DAG.getConstant(1, VT), DAG.getConstant(0, VT), cast(N0.getOperand(2))->get()); - if (SCC.Val) return SCC; + if (SCC.Val && SCC.Val != N && SCC.getOpcode() != ISD::ZERO_EXTEND) + return SCC; } return SDOperand(); @@ -4139,6 +4140,9 @@ SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1, } AddToWorkList(SCC.Val); AddToWorkList(Temp.Val); + + if (N2C->getValue() == 1) + return Temp; // shl setcc result by log2 n2c return DAG.getNode(ISD::SHL, N2.getValueType(), Temp, DAG.getConstant(Log2_64(N2C->getValue()), -- 2.34.1