From 014bf215c3457bb34fee348265e8f63a70b4d503 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Mon, 15 Feb 2010 19:41:07 +0000 Subject: Split SelectionDAGISel::IsLegalAndProfitableToFold to IsLegalToFold and IsProfitableToFold. The generic version of the later simply checks whether the folding candidate has a single use. This allows the target isel routines more flexibility in deciding whether folding makes sense. The specific case we are interested in is folding constant pool loads with multiple uses. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96255 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'lib/CodeGen') diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index da2e6e42a3..eead526f09 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -1341,8 +1341,7 @@ static bool findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse, /// isNonImmUse - Start searching from Root up the DAG to check is Def can /// be reached. Return true if that's the case. However, ignore direct uses /// by ImmedUse (which would be U in the example illustrated in -/// IsLegalAndProfitableToFold) and by Root (which can happen in the store -/// case). +/// IsLegalToFold) and by Root (which can happen in the store case). /// FIXME: to be really generic, we should allow direct use by any node /// that is being folded. But realisticly since we only fold loads which /// have one non-chain use, we only need to watch out for load/op/store @@ -1353,11 +1352,17 @@ static inline bool isNonImmUse(SDNode *Root, SDNode *Def, SDNode *ImmedUse) { return findNonImmUse(Root, Def, ImmedUse, Root, Visited); } -/// IsLegalAndProfitableToFold - Returns true if the specific operand node N of -/// U can be folded during instruction selection that starts at Root and -/// folding N is profitable. -bool SelectionDAGISel::IsLegalAndProfitableToFold(SDNode *N, SDNode *U, - SDNode *Root) const { +/// IsProfitableToFold - Returns true if it's profitable to fold the specific +/// operand node N of U during instruction selection that starts at Root. +bool SelectionDAGISel::IsProfitableToFold(SDValue N, SDNode *U, + SDNode *Root) const { + if (OptLevel == CodeGenOpt::None) return false; + return N.hasOneUse(); +} + +/// IsLegalToFold - Returns true if the specific operand node N of +/// U can be folded during instruction selection that starts at Root. +bool SelectionDAGISel::IsLegalToFold(SDValue N, SDNode *U, SDNode *Root) const { if (OptLevel == CodeGenOpt::None) return false; // If Root use can somehow reach N through a path that that doesn't contain @@ -1411,7 +1416,7 @@ bool SelectionDAGISel::IsLegalAndProfitableToFold(SDNode *N, SDNode *U, VT = Root->getValueType(Root->getNumValues()-1); } - return !isNonImmUse(Root, N, U); + return !isNonImmUse(Root, N.getNode(), U); } SDNode *SelectionDAGISel::Select_INLINEASM(SDNode *N) { -- cgit v1.2.3-70-g09d2