Move the FindCopyInsertPoint method of PHIElimination to a new standalone
function so that it can be shared with StrongPHIElimination.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120951 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp
index 0af0a40..3bc083e 100644
--- a/lib/CodeGen/PHIElimination.cpp
+++ b/lib/CodeGen/PHIElimination.cpp
@@ -15,6 +15,7 @@
#define DEBUG_TYPE "phielim"
#include "PHIElimination.h"
+#include "PHIEliminationUtils.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineDominators.h"
@@ -121,51 +122,7 @@
return true;
}
-// FindCopyInsertPoint - Find a safe place in MBB to insert a copy from SrcReg
-// when following the CFG edge to SuccMBB. This needs to be after any def of
-// SrcReg, but before any subsequent point where control flow might jump out of
-// the basic block.
-MachineBasicBlock::iterator
-llvm::PHIElimination::FindCopyInsertPoint(MachineBasicBlock &MBB,
- MachineBasicBlock &SuccMBB,
- unsigned SrcReg) {
- // Handle the trivial case trivially.
- if (MBB.empty())
- return MBB.begin();
- // Usually, we just want to insert the copy before the first terminator
- // instruction. However, for the edge going to a landing pad, we must insert
- // the copy before the call/invoke instruction.
- if (!SuccMBB.isLandingPad())
- return MBB.getFirstTerminator();
-
- // Discover any defs/uses in this basic block.
- SmallPtrSet<MachineInstr*, 8> DefUsesInMBB;
- for (MachineRegisterInfo::reg_iterator RI = MRI->reg_begin(SrcReg),
- RE = MRI->reg_end(); RI != RE; ++RI) {
- MachineInstr *DefUseMI = &*RI;
- if (DefUseMI->getParent() == &MBB)
- DefUsesInMBB.insert(DefUseMI);
- }
-
- MachineBasicBlock::iterator InsertPoint;
- if (DefUsesInMBB.empty()) {
- // No defs. Insert the copy at the start of the basic block.
- InsertPoint = MBB.begin();
- } else if (DefUsesInMBB.size() == 1) {
- // Insert the copy immediately after the def/use.
- InsertPoint = *DefUsesInMBB.begin();
- ++InsertPoint;
- } else {
- // Insert the copy immediately after the last def/use.
- InsertPoint = MBB.end();
- while (!DefUsesInMBB.count(&*--InsertPoint)) {}
- ++InsertPoint;
- }
-
- // Make sure the copy goes after any phi nodes however.
- return MBB.SkipPHIsAndLabels(InsertPoint);
-}
/// LowerAtomicPHINode - Lower the PHI node at the top of the specified block,
/// under the assuption that it needs to be lowered in a way that supports
@@ -294,7 +251,7 @@
// Find a safe location to insert the copy, this may be the first terminator
// in the block (or end()).
MachineBasicBlock::iterator InsertPos =
- FindCopyInsertPoint(opBlock, MBB, SrcReg);
+ findPHICopyInsertPoint(&opBlock, &MBB, SrcReg);
// Insert the copy.
if (!reusedIncoming && IncomingReg)