Move the decision logic whether it's a good idea to split a critical edge to clients. Also fixed an erroneous check. An edge is only a back edge when the from and to blocks are in the same loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111256 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index f506f12..d351db5 100644
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -439,14 +439,6 @@
if (TII->AnalyzeBranch(*this, TBB, FBB, Cond))
return NULL;
- // Avoid splitting backedges of loops. It would introduce small out-of-line
- // blocks into the loop which is very bad for code placement.
- if (this == Succ)
- return NULL;
- MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>();
- if (MLI->isLoopHeader(Succ))
- return NULL;
-
MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock();
MF->insert(llvm::next(MachineFunction::iterator(this)), NMBB);
DEBUG(dbgs() << "Splitting critical edge:"
@@ -479,7 +471,7 @@
P->getAnalysisIfAvailable<MachineDominatorTree>())
MDT->addNewBlock(NMBB, this);
- if (MLI)
+ if (MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>())
if (MachineLoop *TIL = MLI->getLoopFor(this)) {
// If one or the other blocks were not in a loop, the new block is not
// either, and thus LI doesn't need to be updated.