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-rw-r--r--include/llvm/CodeGen/LiveVariables.h5
-rw-r--r--lib/CodeGen/LiveVariables.cpp45
-rw-r--r--lib/CodeGen/PHIElimination.cpp50
-rw-r--r--lib/CodeGen/PHIElimination.h6
4 files changed, 52 insertions, 54 deletions
diff --git a/include/llvm/CodeGen/LiveVariables.h b/include/llvm/CodeGen/LiveVariables.h
index 39a4b89..a7bf600 100644
--- a/include/llvm/CodeGen/LiveVariables.h
+++ b/include/llvm/CodeGen/LiveVariables.h
@@ -283,6 +283,11 @@ public:
return getVarInfo(Reg).isLiveIn(MBB, Reg, *MRI);
}
+ /// isLiveOut - Determine if Reg is live out from MBB, when not considering
+ /// PHI nodes. This means that Reg is either killed by a successor block or
+ /// passed through one.
+ bool isLiveOut(unsigned Reg, const MachineBasicBlock &MBB);
+
/// addNewBlock - Add a new basic block BB between DomBB and SuccBB. All
/// variables that are live out of DomBB and live into SuccBB will be marked
/// as passing live through BB. This method assumes that the machine code is
diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index 68f80ac..3c88e37 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -720,6 +720,51 @@ bool LiveVariables::VarInfo::isLiveIn(const MachineBasicBlock &MBB,
return findKill(&MBB);
}
+bool LiveVariables::isLiveOut(unsigned Reg, const MachineBasicBlock &MBB) {
+ LiveVariables::VarInfo &VI = getVarInfo(Reg);
+
+ // Loop over all of the successors of the basic block, checking to see if
+ // the value is either live in the block, or if it is killed in the block.
+ std::vector<MachineBasicBlock*> OpSuccBlocks;
+ for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
+ E = MBB.succ_end(); SI != E; ++SI) {
+ MachineBasicBlock *SuccMBB = *SI;
+
+ // Is it alive in this successor?
+ unsigned SuccIdx = SuccMBB->getNumber();
+ if (VI.AliveBlocks.test(SuccIdx))
+ return true;
+ OpSuccBlocks.push_back(SuccMBB);
+ }
+
+ // Check to see if this value is live because there is a use in a successor
+ // that kills it.
+ switch (OpSuccBlocks.size()) {
+ case 1: {
+ MachineBasicBlock *SuccMBB = OpSuccBlocks[0];
+ for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
+ if (VI.Kills[i]->getParent() == SuccMBB)
+ return true;
+ break;
+ }
+ case 2: {
+ MachineBasicBlock *SuccMBB1 = OpSuccBlocks[0], *SuccMBB2 = OpSuccBlocks[1];
+ for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
+ if (VI.Kills[i]->getParent() == SuccMBB1 ||
+ VI.Kills[i]->getParent() == SuccMBB2)
+ return true;
+ break;
+ }
+ default:
+ std::sort(OpSuccBlocks.begin(), OpSuccBlocks.end());
+ for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
+ if (std::binary_search(OpSuccBlocks.begin(), OpSuccBlocks.end(),
+ VI.Kills[i]->getParent()))
+ return true;
+ }
+ return false;
+}
+
/// addNewBlock - Add a new basic block BB as an empty succcessor to DomBB. All
/// variables that are live out of DomBB will be marked as passing live through
/// BB.
diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp
index 2e30cc6..68a1c24 100644
--- a/lib/CodeGen/PHIElimination.cpp
+++ b/lib/CodeGen/PHIElimination.cpp
@@ -287,7 +287,7 @@ void llvm::PHIElimination::LowerAtomicPHINode(
// Okay, if we now know that the value is not live out of the block, we can
// add a kill marker in this block saying that it kills the incoming value!
- if (!ValueIsUsed && !isLiveOut(SrcReg, opBlock, *LV)) {
+ if (!ValueIsUsed && !LV->isLiveOut(SrcReg, opBlock)) {
// In our final twist, we have to decide which instruction kills the
// register. In most cases this is the copy, however, the first
// terminator instruction at the end of the block may also use the value.
@@ -353,59 +353,13 @@ bool llvm::PHIElimination::SplitPHIEdges(MachineFunction &MF,
// We break edges when registers are live out from the predecessor block
// (not considering PHI nodes). If the register is live in to this block
// anyway, we would gain nothing from splitting.
- if (!LV.isLiveIn(Reg, MBB) && isLiveOut(Reg, *PreMBB, LV))
+ if (!LV.isLiveIn(Reg, MBB) && LV.isLiveOut(Reg, *PreMBB))
SplitCriticalEdge(PreMBB, &MBB);
}
}
return true;
}
-bool llvm::PHIElimination::isLiveOut(unsigned Reg, const MachineBasicBlock &MBB,
- LiveVariables &LV) {
- LiveVariables::VarInfo &VI = LV.getVarInfo(Reg);
-
- // Loop over all of the successors of the basic block, checking to see if
- // the value is either live in the block, or if it is killed in the block.
- std::vector<MachineBasicBlock*> OpSuccBlocks;
- for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
- E = MBB.succ_end(); SI != E; ++SI) {
- MachineBasicBlock *SuccMBB = *SI;
-
- // Is it alive in this successor?
- unsigned SuccIdx = SuccMBB->getNumber();
- if (VI.AliveBlocks.test(SuccIdx))
- return true;
- OpSuccBlocks.push_back(SuccMBB);
- }
-
- // Check to see if this value is live because there is a use in a successor
- // that kills it.
- switch (OpSuccBlocks.size()) {
- case 1: {
- MachineBasicBlock *SuccMBB = OpSuccBlocks[0];
- for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
- if (VI.Kills[i]->getParent() == SuccMBB)
- return true;
- break;
- }
- case 2: {
- MachineBasicBlock *SuccMBB1 = OpSuccBlocks[0], *SuccMBB2 = OpSuccBlocks[1];
- for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
- if (VI.Kills[i]->getParent() == SuccMBB1 ||
- VI.Kills[i]->getParent() == SuccMBB2)
- return true;
- break;
- }
- default:
- std::sort(OpSuccBlocks.begin(), OpSuccBlocks.end());
- for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
- if (std::binary_search(OpSuccBlocks.begin(), OpSuccBlocks.end(),
- VI.Kills[i]->getParent()))
- return true;
- }
- return false;
-}
-
MachineBasicBlock *PHIElimination::SplitCriticalEdge(MachineBasicBlock *A,
MachineBasicBlock *B) {
assert(A && B && "Missing MBB end point");
diff --git a/lib/CodeGen/PHIElimination.h b/lib/CodeGen/PHIElimination.h
index f5872cb..b0b71ce 100644
--- a/lib/CodeGen/PHIElimination.h
+++ b/lib/CodeGen/PHIElimination.h
@@ -93,12 +93,6 @@ namespace llvm {
bool SplitPHIEdges(MachineFunction &MF, MachineBasicBlock &MBB,
LiveVariables &LV);
- /// isLiveOut - Determine if Reg is live out from MBB, when not
- /// considering PHI nodes. This means that Reg is either killed by
- /// a successor block or passed through one.
- bool isLiveOut(unsigned Reg, const MachineBasicBlock &MBB,
- LiveVariables &LV);
-
/// SplitCriticalEdge - Split a critical edge from A to B by
/// inserting a new MBB. Update branches in A and PHI instructions
/// in B. Return the new block.
generated by cgit v1.1 at 2025-05-31 20:40:06 +0000