Make if-conversion ignore dbg_value instructions in its analysis. rdar://7797940

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105498 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 23 insertions, 4 deletions

diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index c61fd17e79..2abcb51b4e 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -514,7 +514,15 @@ bool IfConverter::ValidDiamond(BBInfo &TrueBBI, BBInfo &FalseBBI,
 
   MachineBasicBlock::iterator TI = TrueBBI.BB->begin();
   MachineBasicBlock::iterator FI = FalseBBI.BB->begin();
-  while (TI != TrueBBI.BB->end() && FI != FalseBBI.BB->end()) {
+  while (1) {
+    // Skip dbg_value instructions
+    if (TI->isDebugValue())
+      ++TI;
+    if (FI->isDebugValue())
+      ++FI;
+    if (TI == TrueBBI.BB->end() || FI == FalseBBI.BB->end())
+      break;
+
     if (!TI->isIdenticalTo(FI))
       break;
     ++Dups1;
@@ -524,7 +532,15 @@ bool IfConverter::ValidDiamond(BBInfo &TrueBBI, BBInfo &FalseBBI,
 
   TI = firstNonBranchInst(TrueBBI.BB, TII);
   FI = firstNonBranchInst(FalseBBI.BB, TII);
-  while (TI != TrueBBI.BB->begin() && FI != FalseBBI.BB->begin()) {
+  while (1) {
+    // Skip dbg_value instructions
+    if (TI->isDebugValue())
+      --TI;
+    if (FI->isDebugValue())
+      --FI;
+    if (TI == TrueBBI.BB->begin() || FI == FalseBBI.BB->begin())
+      break;
+
     if (!TI->isIdenticalTo(FI))
       break;
     ++Dups2;
@@ -569,6 +585,9 @@ void IfConverter::ScanInstructions(BBInfo &BBI) {
   BBI.ClobbersPred = false;
   for (MachineBasicBlock::iterator I = BBI.BB->begin(), E = BBI.BB->end();
        I != E; ++I) {
+    if (I->isDebugValue())
+      continue;
+
     const TargetInstrDesc &TID = I->getDesc();
     if (TID.isNotDuplicable())
       BBI.CannotBeCopied = true;
@@ -1137,7 +1156,7 @@ void IfConverter::PredicateBlock(BBInfo &BBI,
                                  MachineBasicBlock::iterator E,
                                  SmallVectorImpl<MachineOperand> &Cond) {
   for (MachineBasicBlock::iterator I = BBI.BB->begin(); I != E; ++I) {
-    if (TII->isPredicated(I))
+    if (I->isDebugValue() || TII->isPredicated(I))
       continue;
     if (!TII->PredicateInstruction(I, Cond)) {
 #ifndef NDEBUG
@@ -1174,7 +1193,7 @@ void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
     ToBBI.BB->insert(ToBBI.BB->end(), MI);
     ToBBI.NonPredSize++;
 
-    if (!isPredicated)
+    if (!isPredicated && !MI->isDebugValue())
       if (!TII->PredicateInstruction(MI, Cond)) {
 #ifndef NDEBUG
         dbgs() << "Unable to predicate " << *I << "!\n";