[llvm-exegesis] Early out if the scheduler models have no extra info.

We were calling getExtraProcessorInfo() without checking hasExtraProcessorInfo(), resulting in an assertion.

llvm-svn: 330263
diff --git a/llvm/tools/llvm-exegesis/llvm-exegesis.cpp b/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
index c9dfe84..7768357 100644
--- a/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
+++ b/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
@@ -57,7 +57,7 @@
 void main() {
   if (OpcodeName.empty() == (OpcodeIndex == 0)) {
     llvm::report_fatal_error(
-        "please provide one and only one of 'opcode-index' or 'opcode-name' ");
+        "please provide one and only one of 'opcode-index' or 'opcode-name'");
   }
 
   llvm::InitializeNativeTarget();
@@ -68,6 +68,9 @@
 
   const LLVMState State;
 
+  if (!State.getSubtargetInfo().getSchedModel().hasExtraProcessorInfo())
+    llvm::report_fatal_error("sched model is missing extra processor info!");
+
   unsigned Opcode = OpcodeIndex;
   if (Opcode == 0) {
     // Resolve opcode name -> opcode.