[Assignment Tracking][NFC] Cache debug-info-assignment-tracking modul…

…e flag

This reduces CTMark LTO-O3-g compile time by a geomean of 0.1%.

Reviewed By: jmorse

Differential Revision: https://reviews.llvm.org/D146985

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -1051,6 +1051,8 @@ void SelectionDAGBuilder::init(GCFunctionInfo *gfi, AliasAnalysis *aa,
   Context = DAG.getContext();
   LPadToCallSiteMap.clear();
   SL->init(DAG.getTargetLoweringInfo(), TM, DAG.getDataLayout());
+  AssignmentTrackingEnabled = isAssignmentTrackingEnabled(
+      *DAG.getMachineFunction().getFunction().getParent());
 }
 
 void SelectionDAGBuilder::clear() {
@@ -6113,7 +6115,7 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
   }
   case Intrinsic::dbg_declare: {
     // Debug intrinsics are handled separately in assignment tracking mode.
-    if (isAssignmentTrackingEnabled(*I.getFunction()->getParent()))
+    if (AssignmentTrackingEnabled)
       return;
     // Assume dbg.declare can not currently use DIArgList, i.e.
     // it is non-variadic.
@@ -6208,13 +6210,13 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
   }
   case Intrinsic::dbg_assign: {
     // Debug intrinsics are handled seperately in assignment tracking mode.
-    assert(isAssignmentTrackingEnabled(*I.getFunction()->getParent()) &&
+    assert(AssignmentTrackingEnabled &&
            "expected assignment tracking to be enabled");
     return;
   }
   case Intrinsic::dbg_value: {
     // Debug intrinsics are handled seperately in assignment tracking mode.
-    if (isAssignmentTrackingEnabled(*I.getFunction()->getParent()))
+    if (AssignmentTrackingEnabled)
       return;
     const DbgValueInst &DI = cast<DbgValueInst>(I);
     assert(DI.getVariable() && "Missing variable");

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h

@@ -175,6 +175,10 @@ class SelectionDAGBuilder {
   /// We defer handling these until we do see it.
   MapVector<const Value*, DanglingDebugInfoVector> DanglingDebugInfoMap;
 
+  /// Cache the module flag for whether we should use debug-info assignment
+  /// tracking.
+  bool AssignmentTrackingEnabled = false;
+
 public:
   /// Loads are not emitted to the program immediately.  We bunch them up and
   /// then emit token factor nodes when possible.  This allows us to get simple