handle a single empty alloca; fixes #1919

1 files changed, 3 insertions, 0 deletions

diff --git a/src/analyzer.js b/src/analyzer.js
index 253c5505..17582ea3 100644
--- a/src/analyzer.js
+++ b/src/analyzer.js
@@ -1662,11 +1662,13 @@ function analyzer(data, sidePass) {
   function stackAnalyzer() {
     data.functions.forEach(function(func) {
       var lines = func.labels[0].lines;
+      var hasAlloca = false;
       for (var i = 0; i < lines.length; i++) {
         var item = lines[i];
         if (!item.assignTo || item.intertype != 'alloca' || !isNumber(item.ident)) break;
         item.allocatedSize = func.variables[item.assignTo].impl === VAR_EMULATED ?
           calcAllocatedSize(item.allocatedType)*item.ident: 0;
+        hasAlloca = true;
         if (USE_TYPED_ARRAYS === 2) {
           // We need to keep the stack aligned
           item.allocatedSize = Runtime.forceAlign(item.allocatedSize, Runtime.STACK_ALIGN);
@@ -1682,6 +1684,7 @@ function analyzer(data, sidePass) {
       }
       func.initialStack = index;
       func.otherStackAllocations = false;
+      if (func.initialStack === 0 && hasAlloca) func.otherStackAllocations = true; // a single alloca of zero still requires us to emit stack support code
       while (func.initialStack == 0) { // one-time loop with possible abort in the middle
         // If there is no obvious need for stack management, perhaps we don't need it
         // (we try to optimize that way with SKIP_STACK_IN_SMALL). However,