1 files changed, 0 insertions, 56 deletions
diff --git a/src/passes/MergeBlocks.cpp b/src/passes/MergeBlocks.cpp
index 4999fd234..543c7f89c 100644
--- a/src/passes/MergeBlocks.cpp
+++ b/src/passes/MergeBlocks.cpp
@@ -335,62 +335,6 @@ struct MergeBlocks : public WalkerPass<PostWalker<MergeBlocks>> {
   Pass* create() override { return new MergeBlocks; }
 
   void visitBlock(Block *curr) {
-    // If the block has a single child which is a loop, and the block is named,
-    // then it is the exit for the loop. It's better to move it into the loop,
-    // where it can be better optimized by other passes.
-    // Similar logic for ifs: if the block is an exit for the if, we can
-    // move the block in, consider for example:
-    //    (block $label
-    //     (if (..condition1..)
-    //      (block
-    //       (br_if $label (..condition2..))
-    //       (..code..)
-    //      )
-    //     )
-    //    )
-    // After also merging the blocks, we have
-    //    (if (..condition1..)
-    //     (block $label
-    //      (br_if $label (..condition2..))
-    //      (..code..)
-    //     )
-    //    )
-    // which can be further optimized by other passes.
-    if (curr->name.is() && curr->list.size() == 1) {
-      if (auto* loop = curr->list[0]->dynCast<Loop>()) {
-        curr->list[0] = loop->body;
-        loop->body = curr;
-        auto oldOuterType = curr->type;
-        curr->finalize(curr->type);
-        loop->finalize();
-        // After the flip, the outer type must be the same
-        assert(loop->type == oldOuterType);
-        replaceCurrent(loop);
-      } else if (auto* iff = curr->list[0]->dynCast<If>()) {
-        // The label can't be used in the condition.
-        if (BranchUtils::BranchSeeker::countNamed(iff->condition, curr->name) == 0) {
-          // We can move the block into either arm, if there are no uses in the other.
-          Expression** target = nullptr;
-          if (!iff->ifFalse ||
-              BranchUtils::BranchSeeker::countNamed(iff->ifFalse, curr->name) == 0) {
-            target = &iff->ifTrue;
-          } else if (BranchUtils::BranchSeeker::countNamed(iff->ifTrue, curr->name) == 0) {
-            target = &iff->ifFalse;
-          }
-          if (target) {
-            curr->list[0] = *target;
-            *target = curr;
-            curr->finalize(curr->type);
-            iff->finalize();
-            replaceCurrent(iff);
-            // Note that the type might change, e.g. if the if condition is unreachable
-            // but the block that was on the outside had a break.
-          }
-        }
-      }
-      // Always fall through to optimize the block, which has a new child now.
-    }
-    // Otherwise, do the main merging optimizations.
     optimizeBlock(curr, getModule(), getPassOptions());
   }