Merged r19031 into 3.22 branch.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 9587dd3440e749ae8f9a9f847827daa5526d338e..0a3623051e6a4b87e12086674482e61bdf7ef5b7 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -8050,11 +8050,14 @@ void HOptimizedGraphBuilder::VisitLogicalExpression(BinaryOperation* expr) {
     ASSERT(current_block() != NULL);
     HValue* left_value = Top();
 
-    if (left_value->IsConstant()) {
-      HConstant* left_constant = HConstant::cast(left_value);
-      if ((is_logical_and && left_constant->BooleanValue()) ||
-          (!is_logical_and && !left_constant->BooleanValue())) {
-        Drop(1);  // left_value.
+    // Short-circuit left values that always evaluate to the same boolean value.
+    if (expr->left()->ToBooleanIsTrue() || expr->left()->ToBooleanIsFalse()) {
+      // l (evals true)  && r -> r
+      // l (evals true)  || r -> l
+      // l (evals false) && r -> l
+      // l (evals false) || r -> r
+      if (is_logical_and == expr->left()->ToBooleanIsTrue()) {
+        Drop(1);
         CHECK_ALIVE(VisitForValue(expr->right()));
       }
       return ast_context()->ReturnValue(Pop());