Revert "[RemoveDIs][NFC] Remove dbg intrinsic handling code from SelectionDAG ISel (llvm#144702)"

This reverts commit 36038a1.

Author: ronlieb

llvm/include/llvm/CodeGen/FunctionLoweringInfo.h

@@ -35,6 +35,7 @@ namespace llvm {
 class Argument;
 class BasicBlock;
 class BranchProbabilityInfo;
+class DbgDeclareInst;
 class Function;
 class Instruction;
 class MachineFunction;
@@ -190,8 +191,9 @@ class FunctionLoweringInfo {
   /// The current call site index being processed, if any. 0 if none.
   unsigned CurCallSite = 0;
 
-  /// Collection of dbg_declare instructions handled after argument
+  /// Collection of dbg.declare instructions handled after argument
   /// lowering and before ISel proper.
+  SmallPtrSet<const DbgDeclareInst *, 8> PreprocessedDbgDeclares;
   SmallPtrSet<const DbgVariableRecord *, 8> PreprocessedDVRDeclares;
 
   /// set - Initialize this FunctionLoweringInfo with the given Function

llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp

@@ -369,6 +369,7 @@ void FunctionLoweringInfo::clear() {
   StatepointStackSlots.clear();
   StatepointRelocationMaps.clear();
   PreferredExtendType.clear();
+  PreprocessedDbgDeclares.clear();
   PreprocessedDVRDeclares.clear();
 }
 

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h

@@ -56,6 +56,7 @@ class CleanupPadInst;
 class CleanupReturnInst;
 class Constant;
 class ConstrainedFPIntrinsic;
+class DbgValueInst;
 class DataLayout;
 class DIExpression;
 class DILocalVariable;

llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

@@ -1593,6 +1593,10 @@ static bool processDbgDeclare(FunctionLoweringInfo &FuncInfo,
 /// in case the declarations refer to arguments.
 static void processDbgDeclares(FunctionLoweringInfo &FuncInfo) {
   for (const auto &I : instructions(*FuncInfo.Fn)) {
+    const auto *DI = dyn_cast<DbgDeclareInst>(&I);
+    if (DI && processDbgDeclare(FuncInfo, DI->getAddress(), DI->getExpression(),
+                                DI->getVariable(), DI->getDebugLoc()))
+      FuncInfo.PreprocessedDbgDeclares.insert(DI);
     for (const DbgVariableRecord &DVR : filterDbgVars(I.getDbgRecordRange())) {
       if (DVR.Type == DbgVariableRecord::LocationType::Declare &&
           processDbgDeclare(FuncInfo, DVR.getVariableLocationOp(0),