Author: lattner
Date: Tue Jan 15 23:49:24 2008
New Revision: 46050
URL: http://llvm.org/viewvc/llvm-project?rev=46050&view=rev
Log:
Factor the ReachesChainWithoutSideEffects out of dag combiner into
a public SDOperand::reachesChainWithoutSideEffects method. No
functionality change.
Modified:
llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h?rev=46050&r1=46049&r2=46050&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGNodes.h Tue Jan 15 23:49:24 2008
@@ -780,6 +780,14 @@
inline bool isTargetOpcode() const;
inline unsigned getTargetOpcode() const;
+
+ /// reachesChainWithoutSideEffects - Return true if this operand (which must
+ /// be a chain) reaches the specified operand without crossing any
+ /// side-effecting instructions. In practice, this looks through token
+ /// factors and non-volatile loads. In order to remain efficient, this only
+ /// looks a couple of nodes in, it does not do an exhaustive search.
+ bool reachesChainWithoutSideEffects(SDOperand Dest, unsigned Depth = 2)
const;
+
/// hasOneUse - Return true if there is exactly one operation using this
/// result value of the defining operator.
inline bool hasOneUse() const;
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=46050&r1=46049&r2=46050&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Tue Jan 15 23:49:24 2008
@@ -4122,33 +4122,6 @@
return SDOperand();
}
-/// ReachesChainWithoutSideEffects - Do a little local search to see if Src can
-/// reach Dest without any side effects like a store, or call. Non-volatile
-/// loads are ok though.
-static bool ReachesChainWithoutSideEffects(SDOperand Src, SDOperand Dest,
- unsigned Depth = 0) {
- if (Src == Dest) return true;
-
- // Don't search too deeply, we just want to be able to see through
- // TokenFactor's etc.
- if (Depth == 2) return false;
-
- // If this is a token factor, all inputs to the TF happen in parallel. If
any
- // of the operands of the TF reach dest, then we can do the xform.
- if (Src.getOpcode() == ISD::TokenFactor) {
- for (unsigned i = 0, e = Src.getNumOperands(); i != e; ++i)
- if (ReachesChainWithoutSideEffects(Src.getOperand(i), Dest, Depth+1))
- return true;
- return false;
- }
-
- // Loads don't have side effects, look through them.
- if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Src)) {
- if (!Ld->isVolatile())
- return ReachesChainWithoutSideEffects(Ld->getChain(), Dest, Depth+1);
- }
- return false;
-}
SDOperand DAGCombiner::visitSTORE(SDNode *N) {
StoreSDNode *ST = cast<StoreSDNode>(N);
@@ -4283,7 +4256,7 @@
!ST->isVolatile() &&
// There can't be any side effects between the load and store, such as
// a call or store.
- ReachesChainWithoutSideEffects(Chain, SDOperand(Ld, 1))) {
+ Chain.reachesChainWithoutSideEffects(SDOperand(Ld, 1))) {
// The store is dead, remove it.
return Chain;
}
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=46050&r1=46049&r2=46050&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Tue Jan 15 23:49:24
2008
@@ -3562,6 +3562,37 @@
return false;
}
+/// reachesChainWithoutSideEffects - Return true if this operand (which must
+/// be a chain) reaches the specified operand without crossing any
+/// side-effecting instructions. In practice, this looks through token
+/// factors and non-volatile loads. In order to remain efficient, this only
+/// looks a couple of nodes in, it does not do an exhaustive search.
+bool SDOperand::reachesChainWithoutSideEffects(SDOperand Dest,
+ unsigned Depth) const {
+ if (*this == Dest) return true;
+
+ // Don't search too deeply, we just want to be able to see through
+ // TokenFactor's etc.
+ if (Depth == 0) return false;
+
+ // If this is a token factor, all inputs to the TF happen in parallel. If
any
+ // of the operands of the TF reach dest, then we can do the xform.
+ if (getOpcode() == ISD::TokenFactor) {
+ for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+ if (getOperand(i).reachesChainWithoutSideEffects(Dest, Depth-1))
+ return true;
+ return false;
+ }
+
+ // Loads don't have side effects, look through them.
+ if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(*this)) {
+ if (!Ld->isVolatile())
+ return Ld->getChain().reachesChainWithoutSideEffects(Dest, Depth-1);
+ }
+ return false;
+}
+
+
static void findPredecessor(SDNode *N, const SDNode *P, bool &found,
SmallPtrSet<SDNode *, 32> &Visited) {
if (found || !Visited.insert(N))
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