TableGen: Add missing consts to CodeGenSubRegIndex

Author: arsenm

llvm/utils/TableGen/RegisterInfoEmitter.cpp

@@ -660,17 +660,17 @@ static void printMask(raw_ostream &OS, LaneBitmask Val) {
 // Try to combine Idx's compose map into Vec if it is compatible.
 // Return false if it's not possible.
 static bool combine(const CodeGenSubRegIndex *Idx,
-                    SmallVectorImpl<CodeGenSubRegIndex *> &Vec) {
+                    SmallVectorImpl<const CodeGenSubRegIndex *> &Vec) {
   const CodeGenSubRegIndex::CompMap &Map = Idx->getComposites();
   for (const auto &I : Map) {
-    CodeGenSubRegIndex *&Entry = Vec[I.first->EnumValue - 1];
+    const CodeGenSubRegIndex *&Entry = Vec[I.first->EnumValue - 1];
     if (Entry && Entry != I.second)
       return false;
   }
 
   // All entries are compatible. Make it so.
   for (const auto &I : Map) {
-    auto *&Entry = Vec[I.first->EnumValue - 1];
+    const CodeGenSubRegIndex *&Entry = Vec[I.first->EnumValue - 1];
     assert((!Entry || Entry == I.second) && "Expected EnumValue to be unique");
     Entry = I.second;
   }
@@ -692,7 +692,7 @@ void RegisterInfoEmitter::emitComposeSubRegIndices(raw_ostream &OS,
 
   // Map each Sub-register index to a compatible table row.
   SmallVector<unsigned, 4> RowMap;
-  SmallVector<SmallVector<CodeGenSubRegIndex *, 4>, 4> Rows;
+  SmallVector<SmallVector<const CodeGenSubRegIndex *, 4>, 4> Rows;
 
   auto SubRegIndicesSize =
       std::distance(SubRegIndices.begin(), SubRegIndices.end());