Revert r123419. It still breaks llvm-gcc-i386-linux-selfhost.

llvm-svn: 123423

2 files changed, 7 insertions, 24 deletions

diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp
index 36963875f9e..ad1ab287e34 100644
--- a/llvm/lib/CodeGen/MachineBasicBlock.cpp
+++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp
@@ -155,22 +155,11 @@ MachineBasicBlock::SkipPHIsAndLabels(MachineBasicBlock::iterator I) {
 }
 
 MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() {
-  iterator B = begin(), I = end();
-  iterator Term = I;
-  while (I != B) {
-    --I;
-    // Ignore any debug values after the first terminator.
-    if (I->isDebugValue())
-      continue;
-    // Stop once we see a non-debug non-terminator.
-    if (!I->getDesc().isTerminator())
-      break;
-    // Earliest terminator so far.
-    Term = I;
-  }
-  // Return the first terminator, or end().
-  // Everything after Term is terminators and debug values.
-  return Term;
+  iterator I = end();
+  while (I != begin() && (--I)->getDesc().isTerminator())
+    ; /*noop */
+  if (I != end() && !I->getDesc().isTerminator()) ++I;
+  return I;
 }
 
 MachineBasicBlock::iterator MachineBasicBlock::getLastNonDebugInstr() {
diff --git a/llvm/lib/CodeGen/PHIElimination.cpp b/llvm/lib/CodeGen/PHIElimination.cpp
index b940e269112..923fa213e7b 100644
--- a/llvm/lib/CodeGen/PHIElimination.cpp
+++ b/llvm/lib/CodeGen/PHIElimination.cpp
@@ -339,8 +339,6 @@ void PHIElimination::LowerAtomicPHINode(
 #ifndef NDEBUG
         for (MachineBasicBlock::iterator TI = llvm::next(Term);
              TI != opBlock.end(); ++TI) {
-          if (TI->isDebugValue())
-            continue;
           assert(!TI->readsRegister(SrcReg) &&
                  "Terminator instructions cannot use virtual registers unless"
                  "they are the first terminator in a block!");
@@ -349,13 +347,9 @@ void PHIElimination::LowerAtomicPHINode(
       } else if (reusedIncoming || !IncomingReg) {
         // We may have to rewind a bit if we didn't insert a copy this time.
         KillInst = Term;
-        while (KillInst != opBlock.begin()) {
-          --KillInst;
-          if (KillInst->isDebugValue())
-            continue;
-          if (KillInst->readsRegister(SrcReg))
+        while (KillInst != opBlock.begin())
+          if ((--KillInst)->readsRegister(SrcReg))
             break;
-        }
       } else {
         // We just inserted this copy.
         KillInst = prior(InsertPos);