[Parser] Parse br_if correctly (#6202)

The new text parser and IRBuilder were previously not differentiating between
`br` and `br_if`. Handle `br_if` correctly by popping and assigning a condition.

2 files changed, 11 insertions, 4 deletions

diff --git a/src/wasm/wasm-ir-builder.cpp b/src/wasm/wasm-ir-builder.cpp
index 43a989c6e..e8a2a2386 100644
--- a/src/wasm/wasm-ir-builder.cpp
+++ b/src/wasm/wasm-ir-builder.cpp
@@ -430,6 +430,11 @@ Result<Expression*> IRBuilder::getBranchValue(Name labelName,
 }
 
 Result<> IRBuilder::visitBreak(Break* curr, std::optional<Index> label) {
+  if (curr->condition) {
+    auto cond = pop();
+    CHECK_ERR(cond);
+    curr->condition = *cond;
+  }
   auto value = getBranchValue(curr->name, label);
   CHECK_ERR(value);
   curr->value = *value;
@@ -961,13 +966,15 @@ Result<> IRBuilder::makeLoop(Name label, Type type) {
   return visitLoopStart(loop);
 }
 
-Result<> IRBuilder::makeBreak(Index label) {
+Result<> IRBuilder::makeBreak(Index label, bool isConditional) {
   auto name = getLabelName(label);
   CHECK_ERR(name);
   Break curr;
   curr.name = *name;
+  // Use a dummy condition value if we need to pop a condition.
+  curr.condition = isConditional ? &curr : nullptr;
   CHECK_ERR(visitBreak(&curr, label));
-  push(builder.makeBreak(curr.name, curr.value));
+  push(builder.makeBreak(curr.name, curr.value, curr.condition));
   return Ok{};
 }
 
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 9270a19b0..9dbfc88c2 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -2580,7 +2580,7 @@ Name SExpressionWasmBuilder::getLabel(Element& s, LabelType labelType) {
   }
 }
 
-Expression* SExpressionWasmBuilder::makeBreak(Element& s) {
+Expression* SExpressionWasmBuilder::makeBreak(Element& s, bool isConditional) {
   auto ret = allocator.alloc<Break>();
   size_t i = 1;
   ret->name = getLabel(*s[i]);
@@ -2588,7 +2588,7 @@ Expression* SExpressionWasmBuilder::makeBreak(Element& s) {
   if (i == s.size()) {
     return ret;
   }
-  if (elementStartsWith(s, BR_IF)) {
+  if (isConditional) {
     if (i + 1 < s.size()) {
       ret->value = parseExpression(s[i]);
       i++;