[LateLowerGCFrame] fix PlaceGCFrameReset for returns_twice

src/codegen.cpp

@@ -3232,7 +3232,6 @@ static bool slot_eq(jl_value_t *e, int sl)
 // --- find volatile variables ---
 
 // assigned in a try block and used outside that try block
-
 static bool local_var_occurs(jl_value_t *e, int sl)
 {
     if (slot_eq(e, sl)) {
@@ -3272,13 +3271,13 @@ static bool have_try_block(jl_array_t *stmts)
     return 0;
 }
 
-// conservative marking of all variables potentially used after a catch block that were assigned before it
+// conservative marking of all variables potentially used after a catch block that were assigned after the try
 static void mark_volatile_vars(jl_array_t *stmts, SmallVectorImpl<jl_varinfo_t> &slots, const std::set<int> &bbstarts)
 {
     if (!have_try_block(stmts))
         return;
     size_t slength = jl_array_dim0(stmts);
-    BitVector assigned_in_block(slots.size()); // conservatively only ignore slots assigned in the same basic block
+    BitVector assigned_in_block(slots.size()); // since we don't have domtree access, conservatively only ignore slots assigned in the same basic block
     for (int j = 0; j < (int)slength; j++) {
         if (bbstarts.count(j + 1))
             assigned_in_block.reset();

src/llvm-late-gc-lowering.cpp

@@ -2291,7 +2291,7 @@ void LateLowerGCFrame::PlaceGCFrameStores(State &S, unsigned MinColorRoot,
             const LargeSparseBitVector &NowLive = S.LiveSets[*rit];
             // reset slots which are no longer alive
             for (int Idx : *LastLive) {
-                if (Idx >= PreAssignedColors && !HasBitSet(NowLive, Idx)) {
+                if (Colors[Idx] >= PreAssignedColors && !HasBitSet(NowLive, Idx)) {
                     PlaceGCFrameReset(S, Idx, MinColorRoot, Colors, GCFrame,
                       S.ReverseSafepointNumbering[*rit]);
                 }