Subzero: Randomly insert nops.

src/IceCfgNode.cpp

Index: src/IceCfgNode.cpp
diff --git a/src/IceCfgNode.cpp b/src/IceCfgNode.cpp
index 22915b2f37bbe9f72ca06d10bfba912302543a0a..696a2f0b87ad9fb948535f3ded3d0ece2a0ccfe2 100644
--- a/src/IceCfgNode.cpp
+++ b/src/IceCfgNode.cpp
@@ -191,6 +191,24 @@ void CfgNode::doAddressOpt() {
   }
 }
 
+void CfgNode::doNopInsertion() {
+  TargetLowering *Target = Func->getTarget();
+  LoweringContext &Context = Target->getContext();
+  Context.init(this);
+  while (!Context.atEnd()) {
+    Target->doNopInsertion();
+    // Ensure Cur=Next, so that the nops are inserted before the current
+    // instruction rather than after.
+    Context.advanceNext();
+    Context.advanceCur();
+  }
+  // Insert before all instructions.
+  Context.setInsertPoint(getInsts().begin());
+  Context.advanceNext();
+  Context.advanceCur();
+  Target->doNopInsertion();
+}
+
 // Drives the target lowering.  Passes the current instruction and the
 // next non-deleted instruction for target lowering.
 void CfgNode::genCode() {