- Fix SelectionDAG to generate correct CFGs.

- Add a basic machine-level dead block eliminator.

These two have to go together, since many other parts of the code generator are unable to handle the unreachable blocks otherwise created.

llvm-svn: 54333

llvm/lib/Target/TargetMachine.cpp

@@ -40,6 +40,7 @@ namespace llvm {
   bool RealignStack;
   bool VerboseAsm;
   bool DisableJumpTables;
+  bool DisableCorrectBranchFolding;
 }
 
 static cl::opt<bool, true> PrintCode("print-machineinstrs",
@@ -163,6 +164,11 @@ DisableSwitchTables(cl::Hidden, "disable-jump-tables",
            cl::location(DisableJumpTables),
            cl::init(false));
 
+static cl::opt<bool, true>
+DisableCorrectISelFolding(cl::Hidden, "disable-correct-folding",
+cl::desc("Do not perform correct branch folding in the instruction selector."),
+cl::location(DisableCorrectBranchFolding), cl::init(false));
+
 //---------------------------------------------------------------------------
 // TargetMachine Class
 //