Fix if copying (#1278)

* fix if copying - we should preserve the forced explicit type if there is one, and not just infer it from the arms. this adds a builder method for makeIf that receives a type to apply to the if, and for blocks a method that makes a block from a list, also with a variant with a provided type

2 files changed, 36 insertions, 6 deletions

diff --git a/src/ir/ExpressionManipulator.cpp b/src/ir/ExpressionManipulator.cpp
index aa2a10388..812c4f04b 100644
--- a/src/ir/ExpressionManipulator.cpp
+++ b/src/ir/ExpressionManipulator.cpp
@@ -38,16 +38,14 @@ Expression* flexibleCopy(Expression* original, Module& wasm, CustomCopier custom
     }
 
     Expression* visitBlock(Block *curr) {
-      auto* ret = builder.makeBlock();
+      ExpressionList list(wasm.allocator);
       for (Index i = 0; i < curr->list.size(); i++) {
-        ret->list.push_back(copy(curr->list[i]));
+        list.push_back(copy(curr->list[i]));
       }
-      ret->name = curr->name;
-      ret->finalize(curr->type);
-      return ret;
+      return builder.makeBlock(curr->name, list, curr->type);
     }
     Expression* visitIf(If *curr) {
-      return builder.makeIf(copy(curr->condition), copy(curr->ifTrue), copy(curr->ifFalse));
+      return builder.makeIf(copy(curr->condition), copy(curr->ifTrue), copy(curr->ifFalse), curr->type);
     }
     Expression* visitLoop(Loop *curr) {
       return builder.makeLoop(curr->name, copy(curr->body));
diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index bc670bb8f..8ab4cfec9 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -90,12 +90,44 @@ public:
     ret->finalize();
     return ret;
   }
+  Block* makeBlock(const ExpressionList& items) {
+    auto* ret = allocator.alloc<Block>();
+    ret->list.set(items);
+    ret->finalize();
+    return ret;
+  }
+  Block* makeBlock(const ExpressionList& items, WasmType type) {
+    auto* ret = allocator.alloc<Block>();
+    ret->list.set(items);
+    ret->finalize(type);
+    return ret;
+  }
+  Block* makeBlock(Name name, const ExpressionList& items) {
+    auto* ret = allocator.alloc<Block>();
+    ret->name = name;
+    ret->list.set(items);
+    ret->finalize();
+    return ret;
+  }
+  Block* makeBlock(Name name, const ExpressionList& items, WasmType type) {
+    auto* ret = allocator.alloc<Block>();
+    ret->name = name;
+    ret->list.set(items);
+    ret->finalize(type);
+    return ret;
+  }
   If* makeIf(Expression* condition, Expression* ifTrue, Expression* ifFalse = nullptr) {
     auto* ret = allocator.alloc<If>();
     ret->condition = condition; ret->ifTrue = ifTrue; ret->ifFalse = ifFalse;
     ret->finalize();
     return ret;
   }
+  If* makeIf(Expression* condition, Expression* ifTrue, Expression* ifFalse, WasmType type) {
+    auto* ret = allocator.alloc<If>();
+    ret->condition = condition; ret->ifTrue = ifTrue; ret->ifFalse = ifFalse;
+    ret->finalize(type);
+    return ret;
+  }
   Loop* makeLoop(Name name, Expression* body) {
     auto* ret = allocator.alloc<Loop>();
     ret->name = name; ret->body = body;