Revert r133607. This is causing failures in the Clang gccTestSuite.
Specifically, gcc.c-torture/compile/pr21356.c.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133646 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TailDuplication.cpp b/lib/CodeGen/TailDuplication.cpp
index 6e832d9..d16369a 100644
--- a/lib/CodeGen/TailDuplication.cpp
+++ b/lib/CodeGen/TailDuplication.cpp
@@ -568,9 +568,9 @@
TailDuplicatePass::isSimpleBB(MachineBasicBlock *TailBB) {
if (TailBB->succ_size() != 1)
return false;
- MachineBasicBlock::iterator I = TailBB->begin();
+ MachineBasicBlock::iterator I = TailBB->getFirstNonPHI();
MachineBasicBlock::iterator E = TailBB->end();
- while (I != E && I->isDebugValue())
+ while (I->isDebugValue() && I != E)
++I;
if (I == E)
return true;
@@ -712,7 +712,7 @@
DenseSet<unsigned> UsedByPhi;
getRegsUsedByPHIs(*TailBB, &UsedByPhi);
- if (isSimpleBB(TailBB))
+ if (0 && isSimpleBB(TailBB))
return duplicateSimpleBB(TailBB, TDBBs, UsedByPhi, Copies);
// Iterate through all the unique predecessors and tail-duplicate this