Addressed some more review comments

Author: rastogishubham

llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp

@@ -976,14 +976,18 @@ static void addDebugSubstitutionsToTable(MachineFunction *MF,
   // OriginalInstr in the new MergedInstr.
   auto Reg = OriginalInstr.getOperand(0).getReg();
   unsigned OperandNo = 0;
-  for (auto Op : MergedInstr.operands()) {
-    if (Op.getReg() == Reg)
+  bool RegFound = false;
+  for (const auto Op : MergedInstr.operands()) {
+    if (Op.getReg() == Reg) {
+      RegFound = true;
       break;
+    }
     OperandNo++;
   }
 
-  MF->makeDebugValueSubstitution({OriginalInstr.peekDebugInstrNum(), 0},
-                                 {InstrNumToSet, OperandNo});
+  if (RegFound)
+    MF->makeDebugValueSubstitution({OriginalInstr.peekDebugInstrNum(), 0},
+                                   {InstrNumToSet, OperandNo});
 }
 
 MachineBasicBlock::iterator
@@ -1264,15 +1268,6 @@ AArch64LoadStoreOpt::mergePairedInsns(MachineBasicBlock::iterator I,
     // DBG_INSTR_REF !7, dbg-instr-ref(1, 0), debug-location !9
     // DBG_INSTR_REF !8, dbg-instr-ref(2, 0), debug-location !9
 
-    // $x0 is where the final value is stored, so the sign extend (SBFMXri)
-    // instruction contains the final value we care about we give it a new
-    // debug-instr-number 3. Whereas, $w1 contains the final value that we care
-    // about, therefore the LDP instruction is also given a new
-    // debug-instr-number 4. We have to add these subsitutions to the
-    // debugValueSubstitutions table. However, we also have to ensure that the
-    // OpIndex that pointed to debug-instr-number 1 gets updated to 1, because
-    // $w1 is the second operand of the LDP instruction.
-
     // We want the final result to look like:
     // debugValueSubstitutions:
     // - { srcinst: 1, srcop: 0, dstinst: 4, dstop: 1, subreg: 0 }
@@ -1283,6 +1278,15 @@ AArch64LoadStoreOpt::mergePairedInsns(MachineBasicBlock::iterator I,
     // DBG_INSTR_REF !7, dbg-instr-ref(1, 0), debug-location !9
     // DBG_INSTR_REF !8, dbg-instr-ref(2, 0), debug-location !9
 
+    // $x0 is where the final value is stored, so the sign extend (SBFMXri)
+    // instruction contains the final value we care about we give it a new
+    // debug-instr-number 3. Whereas, $w1 contains the final value that we care
+    // about, therefore the LDP instruction is also given a new
+    // debug-instr-number 4. We have to add these subsitutions to the
+    // debugValueSubstitutions table. However, we also have to ensure that the
+    // OpIndex that pointed to debug-instr-number 1 gets updated to 1, because
+    // $w1 is the second operand of the LDP instruction.
+
     if (I->peekDebugInstrNum()) {
       // If I is the instruction which got sign extended and has a
       // debug-instr-number, give the SBFMXri instruction a new
@@ -1349,10 +1353,6 @@ AArch64LoadStoreOpt::mergePairedInsns(MachineBasicBlock::iterator I,
     // DBG_INSTR_REF !12, dbg-instr-ref(1, 0), debug-location !14
     // DBG_INSTR_REF !13, dbg-instr-ref(2, 0), debug-location !14
 
-    // Here all that needs to be done is, that the LDP instruction needs to be
-    // updated with a new debug-instr-number, we then need to add entries into
-    // the debugSubstitutions table to map the old instr-refs to the new ones.
-
     // We want the final result to look like:
     // debugValueSubstitutions:
     // - { srcinst: 1, srcop: 0, dstinst: 3, dstop: 1, subreg: 0 }
@@ -1361,8 +1361,11 @@ AArch64LoadStoreOpt::mergePairedInsns(MachineBasicBlock::iterator I,
     // DBG_INSTR_REF !12, dbg-instr-ref(1, 0), debug-location !14
     // DBG_INSTR_REF !12, dbg-instr-ref(2, 0), debug-location !14
 
-    // Assign new DebugInstrNum to the Paired instruction.
+    // Here all that needs to be done is, that the LDP instruction needs to be
+    // updated with a new debug-instr-number, we then need to add entries into
+    // the debugSubstitutions table to map the old instr-refs to the new ones.
 
+    // Assign new DebugInstrNum to the Paired instruction.
     if (I->peekDebugInstrNum()) {
       unsigned NewDebugInstrNum = MIB->getDebugInstrNum();
       addDebugSubstitutionsToTable(MBB->getParent(), NewDebugInstrNum, *I,