[llvm-commits] [llvm] r71241 - in /llvm/trunk: include/llvm/CodeGen/SelectionDAGISel.h lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp lib/Target/X86/X86ISelDAGToDAG.cpp
Anton Korobeynikov
asl at math.spbu.ru
Fri May 8 11:51:58 PDT 2009
Author: asl
Date: Fri May 8 13:51:58 2009
New Revision: 71241
URL: http://llvm.org/viewvc/llvm-project?rev=71241&view=rev
Log:
Factor out cycle-finder code and make it generic.
Modified:
llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h?rev=71241&r1=71240&r2=71241&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h Fri May 8 13:51:58 2009
@@ -88,10 +88,8 @@
/// U can be folded during instruction selection that starts at Root and
/// folding N is profitable.
virtual
- bool IsLegalAndProfitableToFold(SDNode *N, SDNode *U, SDNode *Root) const {
- return true;
- }
-
+ bool IsLegalAndProfitableToFold(SDNode *N, SDNode *U, SDNode *Root) const;
+
/// CreateTargetHazardRecognizer - Return a newly allocated hazard recognizer
/// to use for this target when scheduling the DAG.
virtual ScheduleHazardRecognizer *CreateTargetHazardRecognizer();
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp?rev=71241&r1=71240&r2=71241&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Fri May 8 13:51:58 2009
@@ -1203,4 +1203,120 @@
Ops.push_back(InOps.back());
}
+/// findFlagUse - Return use of MVT::Flag value produced by the specified
+/// SDNode.
+///
+static SDNode *findFlagUse(SDNode *N) {
+ unsigned FlagResNo = N->getNumValues()-1;
+ for (SDNode::use_iterator I = N->use_begin(), E = N->use_end(); I != E; ++I) {
+ SDUse &Use = I.getUse();
+ if (Use.getResNo() == FlagResNo)
+ return Use.getUser();
+ }
+ return NULL;
+}
+
+/// findNonImmUse - Return true if "Use" is a non-immediate use of "Def".
+/// This function recursively traverses up the operand chain, ignoring
+/// certain nodes.
+static bool findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse,
+ SDNode *Root,
+ SmallPtrSet<SDNode*, 16> &Visited) {
+ if (Use->getNodeId() < Def->getNodeId() ||
+ !Visited.insert(Use))
+ return false;
+
+ for (unsigned i = 0, e = Use->getNumOperands(); i != e; ++i) {
+ SDNode *N = Use->getOperand(i).getNode();
+ if (N == Def) {
+ if (Use == ImmedUse || Use == Root)
+ continue; // We are not looking for immediate use.
+ assert(N != Root);
+ return true;
+ }
+
+ // Traverse up the operand chain.
+ if (findNonImmUse(N, Def, ImmedUse, Root, Visited))
+ return true;
+ }
+ return false;
+}
+
+/// 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).
+/// 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
+/// and load/op/cmp case where the root (store / cmp) may reach the load via
+/// its chain operand.
+static inline bool isNonImmUse(SDNode *Root, SDNode *Def, SDNode *ImmedUse) {
+ SmallPtrSet<SDNode*, 16> Visited;
+ 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 {
+ if (OptLevel == CodeGenOpt::None) return false;
+
+ // If Root use can somehow reach N through a path that that doesn't contain
+ // U then folding N would create a cycle. e.g. In the following
+ // diagram, Root can reach N through X. If N is folded into into Root, then
+ // X is both a predecessor and a successor of U.
+ //
+ // [N*] //
+ // ^ ^ //
+ // / \ //
+ // [U*] [X]? //
+ // ^ ^ //
+ // \ / //
+ // \ / //
+ // [Root*] //
+ //
+ // * indicates nodes to be folded together.
+ //
+ // If Root produces a flag, then it gets (even more) interesting. Since it
+ // will be "glued" together with its flag use in the scheduler, we need to
+ // check if it might reach N.
+ //
+ // [N*] //
+ // ^ ^ //
+ // / \ //
+ // [U*] [X]? //
+ // ^ ^ //
+ // \ \ //
+ // \ | //
+ // [Root*] | //
+ // ^ | //
+ // f | //
+ // | / //
+ // [Y] / //
+ // ^ / //
+ // f / //
+ // | / //
+ // [FU] //
+ //
+ // If FU (flag use) indirectly reaches N (the load), and Root folds N
+ // (call it Fold), then X is a predecessor of FU and a successor of
+ // Fold. But since Fold and FU are flagged together, this will create
+ // a cycle in the scheduling graph.
+
+ MVT VT = Root->getValueType(Root->getNumValues()-1);
+ while (VT == MVT::Flag) {
+ SDNode *FU = findFlagUse(Root);
+ if (FU == NULL)
+ break;
+ Root = FU;
+ VT = Root->getValueType(Root->getNumValues()-1);
+ }
+
+ return !isNonImmUse(Root, N, U);
+}
+
+
char SelectionDAGISel::ID = 0;
Modified: llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp?rev=71241&r1=71240&r2=71241&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp Fri May 8 13:51:58 2009
@@ -249,60 +249,6 @@
};
}
-/// findFlagUse - Return use of MVT::Flag value produced by the specified
-/// SDNode.
-///
-static SDNode *findFlagUse(SDNode *N) {
- unsigned FlagResNo = N->getNumValues()-1;
- for (SDNode::use_iterator I = N->use_begin(), E = N->use_end(); I != E; ++I) {
- SDUse &Use = I.getUse();
- if (Use.getResNo() == FlagResNo)
- return Use.getUser();
- }
- return NULL;
-}
-
-/// findNonImmUse - Return true if "Use" is a non-immediate use of "Def".
-/// This function recursively traverses up the operand chain, ignoring
-/// certain nodes.
-static bool findNonImmUse(SDNode *Use, SDNode* Def, SDNode *ImmedUse,
- SDNode *Root,
- SmallPtrSet<SDNode*, 16> &Visited) {
- if (Use->getNodeId() < Def->getNodeId() ||
- !Visited.insert(Use))
- return false;
-
- for (unsigned i = 0, e = Use->getNumOperands(); i != e; ++i) {
- SDNode *N = Use->getOperand(i).getNode();
- if (N == Def) {
- if (Use == ImmedUse || Use == Root)
- continue; // We are not looking for immediate use.
- assert(N != Root);
- return true;
- }
-
- // Traverse up the operand chain.
- if (findNonImmUse(N, Def, ImmedUse, Root, Visited))
- return true;
- }
- return false;
-}
-
-/// 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).
-/// 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
-/// and load/op/cmp case where the root (store / cmp) may reach the load via
-/// its chain operand.
-static inline bool isNonImmUse(SDNode *Root, SDNode *Def, SDNode *ImmedUse) {
- SmallPtrSet<SDNode*, 16> Visited;
- return findNonImmUse(Root, Def, ImmedUse, Root, Visited);
-}
-
bool X86DAGToDAGISel::IsLegalAndProfitableToFold(SDNode *N, SDNode *U,
SDNode *Root) const {
@@ -351,58 +297,8 @@
}
}
- // If Root use can somehow reach N through a path that that doesn't contain
- // U then folding N would create a cycle. e.g. In the following
- // diagram, Root can reach N through X. If N is folded into into Root, then
- // X is both a predecessor and a successor of U.
- //
- // [N*] //
- // ^ ^ //
- // / \ //
- // [U*] [X]? //
- // ^ ^ //
- // \ / //
- // \ / //
- // [Root*] //
- //
- // * indicates nodes to be folded together.
- //
- // If Root produces a flag, then it gets (even more) interesting. Since it
- // will be "glued" together with its flag use in the scheduler, we need to
- // check if it might reach N.
- //
- // [N*] //
- // ^ ^ //
- // / \ //
- // [U*] [X]? //
- // ^ ^ //
- // \ \ //
- // \ | //
- // [Root*] | //
- // ^ | //
- // f | //
- // | / //
- // [Y] / //
- // ^ / //
- // f / //
- // | / //
- // [FU] //
- //
- // If FU (flag use) indirectly reaches N (the load), and Root folds N
- // (call it Fold), then X is a predecessor of FU and a successor of
- // Fold. But since Fold and FU are flagged together, this will create
- // a cycle in the scheduling graph.
-
- MVT VT = Root->getValueType(Root->getNumValues()-1);
- while (VT == MVT::Flag) {
- SDNode *FU = findFlagUse(Root);
- if (FU == NULL)
- break;
- Root = FU;
- VT = Root->getValueType(Root->getNumValues()-1);
- }
-
- return !isNonImmUse(Root, N, U);
+ // Proceed to 'generic' cycle finder code
+ return SelectionDAGISel::IsLegalAndProfitableToFold(N, U, Root);
}
/// MoveBelowTokenFactor - Replace TokenFactor operand with load's chain operand
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