3 files changed, 79 insertions, 13 deletions

diff --git a/src/passes/DeadCodeElimination.cpp b/src/passes/DeadCodeElimination.cpp
index 33a52a09a..0555ff1f0 100644
--- a/src/passes/DeadCodeElimination.cpp
+++ b/src/passes/DeadCodeElimination.cpp
@@ -81,7 +81,11 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
         block->list.resize(2);
         block->list[0] = drop(curr->value);
         block->list[1] = curr->condition;
-        block->finalize();
+        // if we previously returned a value, then this block
+        // must have the same type, so it fits in the ast
+        // properly. it ends in an unreachable
+        // anyhow, so that is ok.
+        block->finalize(curr->type);
         replaceCurrent(block);
       } else {
         replaceCurrent(curr->condition);
@@ -105,7 +109,7 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
         block->list.resize(2);
         block->list[0] = drop(curr->value);
         block->list[1] = curr->condition;
-        block->finalize();
+        block->finalize(curr->type);
         replaceCurrent(block);
       } else {
         replaceCurrent(curr->condition);
@@ -271,8 +275,9 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
 
   // other things
 
+  // we don't need to drop unreachable nodes
   Expression* drop(Expression* toDrop) {
-    if (toDrop->is<Unreachable>()) return toDrop;
+    if (toDrop->type == unreachable) return toDrop;
     return Builder(*getModule()).makeDrop(toDrop);
   }
 
@@ -288,7 +293,7 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
           for (; j < newSize; j++) {
             block->list[j] = drop(curr->operands[j]);
           }
-          block->finalize();
+          block->finalize(curr->type);
           return replaceCurrent(block);
         } else {
           return replaceCurrent(curr->operands[i]);
@@ -314,7 +319,7 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
         block->list.push_back(drop(operand));
       }
       block->list.push_back(curr->target);
-      block->finalize();
+      block->finalize(curr->type);
       replaceCurrent(block);
     }
   }
@@ -341,7 +346,7 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
       block->list.resize(2);
       block->list[0] = drop(curr->ptr);
       block->list[1] = curr->value;
-      block->finalize();
+      block->finalize(curr->type);
       replaceCurrent(block);
     }
   }
@@ -362,7 +367,7 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
       block->list.resize(2);
       block->list[0] = drop(curr->left);
       block->list[1] = curr->right;
-      block->finalize();
+      block->finalize(curr->type);
       replaceCurrent(block);
     }
   }
@@ -377,7 +382,7 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
       block->list.resize(2);
       block->list[0] = drop(curr->ifTrue);
       block->list[1] = curr->ifFalse;
-      block->finalize();
+      block->finalize(curr->type);
       replaceCurrent(block);
       return;
     }
@@ -387,7 +392,7 @@ struct DeadCodeElimination : public WalkerPass<PostWalker<DeadCodeElimination>>
       block->list[0] = drop(curr->ifTrue);
       block->list[1] = drop(curr->ifFalse);
       block->list[2] = curr->condition;
-      block->finalize();
+      block->finalize(curr->type);
       replaceCurrent(block);
       return;
     }
diff --git a/test/passes/dce.txt b/test/passes/dce.txt
index 22189fb66..6aaad92b5 100644
--- a/test/passes/dce.txt
+++ b/test/passes/dce.txt
@@ -3,6 +3,7 @@
  (type $1 (func))
  (type $2 (func (result i32)))
  (type $3 (func (param i32) (result i32)))
+ (type $4 (func (param i64 i64) (result i64)))
  (global $x (mut i32) (i32.const 0))
  (table 1 1 anyfunc)
  (elem (i32.const 0) $call-me)
@@ -234,7 +235,7 @@
   (if
    (i32.const 88)
    (drop
-    (block
+    (block i32
      (drop
       (i32.const 0)
      )
@@ -249,7 +250,7 @@
   (if
    (i32.const 100)
    (drop
-    (block
+    (block i32
      (drop
       (i32.const 123)
      )
@@ -263,7 +264,7 @@
   (if
    (i32.const 101)
    (drop
-    (block
+    (block i32
      (drop
       (i32.const 123)
      )
@@ -366,7 +367,7 @@
     (br $label$0
      (block $label$1 i32
       (drop
-       (block
+       (block i32
         (drop
          (i32.const 4104)
         )
@@ -379,4 +380,35 @@
    )
   )
  )
+ (func $call-unreach (type $4) (param $var$0 i64) (param $var$1 i64) (result i64)
+  (local $2 i64)
+  (if i64
+   (i64.eqz
+    (get_local $var$0)
+   )
+   (block $label$0 i64
+    (get_local $var$1)
+   )
+   (block $label$1 i64
+    (call $call-unreach
+     (i64.sub
+      (get_local $var$0)
+      (i64.const 1)
+     )
+     (block i64
+      (drop
+       (block $block i64
+        (set_local $2
+         (get_local $var$0)
+        )
+        (nop)
+        (get_local $2)
+       )
+      )
+      (unreachable)
+     )
+    )
+   )
+  )
+ )
 )
diff --git a/test/passes/dce.wast b/test/passes/dce.wast
index 865f373cf..87a5757cd 100644
--- a/test/passes/dce.wast
+++ b/test/passes/dce.wast
@@ -509,4 +509,33 @@
    )
   )
  )
+ (func $call-unreach (param $var$0 i64) (param $var$1 i64) (result i64)
+  (local $2 i64)
+  (if i64
+   (i64.eqz
+    (get_local $var$0)
+   )
+   (block $label$0 i64
+    (get_local $var$1)
+   )
+   (block $label$1 i64
+    (call $call-unreach
+     (i64.sub
+      (get_local $var$0)
+      (i64.const 1)
+     )
+     (i64.mul
+      (block i64
+       (set_local $2
+        (get_local $var$0)
+       )
+       (nop)
+       (get_local $2)
+      )
+      (unreachable)
+     )
+    )
+   )
+  )
+ )
 )