[llvm-reduce] Check if module data strings are empty before attemptin…

…g to reduce

llvm/tools/llvm-reduce/deltas/ReduceModuleData.cpp

@@ -17,20 +17,36 @@ using namespace llvm;
 static void clearModuleData(std::vector<Chunk> ChunksToKeep, Module *Program) {
   Oracle O(ChunksToKeep);
 
-  if (!O.shouldKeep())
+  if (!Program->getModuleIdentifier().empty() && !O.shouldKeep())
     Program->setModuleIdentifier("");
-  if (!O.shouldKeep())
+  if (!Program->getSourceFileName().empty() && !O.shouldKeep())
     Program->setSourceFileName("");
-  if (!O.shouldKeep())
+  if (!Program->getDataLayoutStr().empty() && !O.shouldKeep())
     Program->setDataLayout("");
-  if (!O.shouldKeep())
+  if (!Program->getTargetTriple().empty() && !O.shouldKeep())
     Program->setTargetTriple("");
   // TODO: clear line by line rather than all at once
-  if (!O.shouldKeep())
+  if (!Program->getModuleInlineAsm().empty() && !O.shouldKeep())
     Program->setModuleInlineAsm("");
 }
 
+static int countModuleData(Module *M) {
+  int Count = 0;
+  if (!M->getModuleIdentifier().empty())
+    ++Count;
+  if (!M->getSourceFileName().empty())
+    ++Count;
+  if (!M->getDataLayoutStr().empty())
+    ++Count;
+  if (!M->getTargetTriple().empty())
+    ++Count;
+  if (!M->getModuleInlineAsm().empty())
+    ++Count;
+  return Count;
+}
+
 void llvm::reduceModuleDataDeltaPass(TestRunner &Test) {
   outs() << "*** Reducing Module Data...\n";
-  runDeltaPass(Test, 5, clearModuleData);
+  int Count = countModuleData(Test.getProgram());
+  runDeltaPass(Test, Count, clearModuleData);
 }