[AMDGPU] Propagate debug locations for compiler-generated instructions

Fixes missing debug locations ("Line 0" in DWARF) for several categories
of compiler-generated instructions in the AMDGPU backend

Author: aleksandar-amd

llvm/include/llvm/CodeGen/SelectionDAGNodes.h

@@ -1743,8 +1743,8 @@ class ConstantSDNode : public SDNode {
   const ConstantInt *Value;
 
   ConstantSDNode(bool isTarget, bool isOpaque, const ConstantInt *val,
-                 SDVTList VTs)
-      : SDNode(isTarget ? ISD::TargetConstant : ISD::Constant, 0, DebugLoc(),
+                 SDVTList VTs, const DebugLoc &DL)
+      : SDNode(isTarget ? ISD::TargetConstant : ISD::Constant, 0, DL,
                VTs),
         Value(val) {
     assert(!isa<VectorType>(val->getType()) && "Unexpected vector type!");

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -1766,7 +1766,7 @@ SDValue SelectionDAG::getConstant(const ConstantInt &Val, const SDLoc &DL,
       return SDValue(N, 0);
 
   if (!N) {
-    N = newSDNode<ConstantSDNode>(isT, isO, Elt, VTs);
+    N = newSDNode<ConstantSDNode>(isT, isO, Elt, VTs, DL.getDebugLoc());
     CSEMap.InsertNode(N, IP);
     InsertNode(N);
     NewSDValueDbgMsg(SDValue(N, 0), "Creating constant: ", this);

llvm/lib/Target/AMDGPU/SIWholeQuadMode.cpp

@@ -1180,15 +1180,16 @@ void SIWholeQuadMode::toExact(MachineBasicBlock &MBB,
     }
   }
 
+  const DebugLoc &DL = MBB.findDebugLoc(Before);
   MachineInstr *MI;
 
   if (SaveWQM) {
     unsigned Opcode = IsTerminator ? AndSaveExecTermOpc : AndSaveExecOpc;
-    MI = BuildMI(MBB, Before, DebugLoc(), TII->get(Opcode), SaveWQM)
+    MI = BuildMI(MBB, Before, DL, TII->get(Opcode), SaveWQM)
              .addReg(LiveMaskReg);
   } else {
     unsigned Opcode = IsTerminator ? AndTermOpc : AndOpc;
-    MI = BuildMI(MBB, Before, DebugLoc(), TII->get(Opcode), Exec)
+    MI = BuildMI(MBB, Before, DL, TII->get(Opcode), Exec)
              .addReg(Exec)
              .addReg(LiveMaskReg);
   }
@@ -1200,13 +1201,14 @@ void SIWholeQuadMode::toExact(MachineBasicBlock &MBB,
 void SIWholeQuadMode::toWQM(MachineBasicBlock &MBB,
                             MachineBasicBlock::iterator Before,
                             Register SavedWQM) {
+  const DebugLoc &DL = MBB.findDebugLoc(Before);
   MachineInstr *MI;
 
   if (SavedWQM) {
-    MI = BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::COPY), Exec)
+    MI = BuildMI(MBB, Before, DL, TII->get(AMDGPU::COPY), Exec)
              .addReg(SavedWQM);
   } else {
-    MI = BuildMI(MBB, Before, DebugLoc(), TII->get(WQMOpc), Exec).addReg(Exec);
+    MI = BuildMI(MBB, Before, DL, TII->get(WQMOpc), Exec).addReg(Exec);
   }
 
   LIS->InsertMachineInstrInMaps(*MI);
@@ -1221,12 +1223,14 @@ void SIWholeQuadMode::toStrictMode(MachineBasicBlock &MBB,
   assert(StrictStateNeeded == StateStrictWWM ||
          StrictStateNeeded == StateStrictWQM);
 
+  const DebugLoc &DL = MBB.findDebugLoc(Before);
+
   if (StrictStateNeeded == StateStrictWWM) {
-    MI = BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::ENTER_STRICT_WWM),
+    MI = BuildMI(MBB, Before, DL, TII->get(AMDGPU::ENTER_STRICT_WWM),
                  SaveOrig)
              .addImm(-1);
   } else {
-    MI = BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::ENTER_STRICT_WQM),
+    MI = BuildMI(MBB, Before, DL, TII->get(AMDGPU::ENTER_STRICT_WQM),
                  SaveOrig)
              .addImm(-1);
   }
@@ -1244,12 +1248,14 @@ void SIWholeQuadMode::fromStrictMode(MachineBasicBlock &MBB,
   assert(CurrentStrictState == StateStrictWWM ||
          CurrentStrictState == StateStrictWQM);
 
+  const DebugLoc &DL = MBB.findDebugLoc(Before);
+
   if (CurrentStrictState == StateStrictWWM) {
-    MI = BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::EXIT_STRICT_WWM),
+    MI = BuildMI(MBB, Before, DL, TII->get(AMDGPU::EXIT_STRICT_WWM),
                  Exec)
              .addReg(SavedOrig);
   } else {
-    MI = BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::EXIT_STRICT_WQM),
+    MI = BuildMI(MBB, Before, DL, TII->get(AMDGPU::EXIT_STRICT_WQM),
                  Exec)
              .addReg(SavedOrig);
   }