Add a new MachineInstr-level DCE pass. It is very simple, and is intended to

be used with fast-isel.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56268 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/LinkAllCodegenComponents.h

@@ -29,6 +29,8 @@ namespace {
       if (std::getenv("bar") != (char*) -1)
         return;
 
+      (void) llvm::createDeadMachineInstructionElimPass();
+
       (void) llvm::createSimpleRegisterAllocator();
       (void) llvm::createLocalRegisterAllocator();
       (void) llvm::createBigBlockRegisterAllocator();

include/llvm/CodeGen/Passes.h

@@ -75,6 +75,11 @@ namespace llvm {
   /// machine basic blocks.
   extern const PassInfo *const UnreachableMachineBlockElimID;
 
+  /// DeadMachineInstructionElim pass - This pass removes dead machine
+  /// instructions.
+  ///
+  FunctionPass *createDeadMachineInstructionElimPass();
+
   /// Creates a register allocator as the user specified on the command line.
   ///
   FunctionPass *createRegisterAllocator();