Add a quick and dirty "loop aligner pass". x86 uses it to align its loops to 16-byte boundaries.

llvm-svn: 47703
diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 115e490..20b0d2a 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -604,7 +604,7 @@
        I != E; ++I) {
     // Print a label for the basic block.
     if (I != MF.begin()) {
-      printBasicBlockLabel(I, true);
+      printBasicBlockLabel(I, true, true);
       O << '\n';
     }
     for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
@@ -838,7 +838,7 @@
        I != E; ++I) {
     // Print a label for the basic block.
     if (I != MF.begin()) {
-      printBasicBlockLabel(I, true);
+      printBasicBlockLabel(I, true, true);
       O << '\n';
     }
     for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();