This survived a bootstrap, so let's try 98104 again.

[oota-llvm.git] / lib / CodeGen / BranchFolding.cpp

diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index adf1c1415274f49cdbe98191d79c409f77735179..889763ac1c8ef6deacfc5e115d701a6d2ec58ab5 100644 (file)
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -971,6 +971,18 @@ bool BranchFolder::OptimizeBranches(MachineFunction &MF) {
   return MadeChange;
 }
 
+// Blocks should be considered empty if they contain only debug info;
+// else the debug info would affect codegen.
+static bool IsEmptyBlock(MachineBasicBlock *MBB) {
+  if (MBB->empty())
+    return true;
+  for (MachineBasicBlock::iterator MBBI = MBB->begin(), MBBE = MBB->end();
+       MBBI!=MBBE; ++MBBI) {
+    if (!MBBI->isDebugValue())
+      return false;
+  }
+  return true;
+}
 
 /// IsBetterFallthrough - Return true if it would be clearly better to
 /// fall-through to MBB1 than to fall through into MBB2.  This has to return
@@ -1008,7 +1020,7 @@ ReoptimizeBlock:
   // explicitly.  Landing pads should not do this since the landing-pad table
   // points to this block.  Blocks with their addresses taken shouldn't be
   // optimized away.
-  if (MBB->empty() && !MBB->isLandingPad() && !MBB->hasAddressTaken()) {
+  if (IsEmptyBlock(MBB) && !MBB->isLandingPad() && !MBB->hasAddressTaken()) {
     // Dead block?  Leave for cleanup later.
     if (MBB->pred_empty()) return MadeChange;