commit 66c404a26e9fdbf1d938b49afadce95de67a7f1e
author Stephen Adams <sra@google.com> Tue Feb 12 18:34:34 2019 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> Tue Feb 12 18:34:34 2019 +0000
tree d15d801d2fb85658b876cebfd54be30d1191e42d
parent c812d5a373f7fe02eb9b68b607bcb230c33ef3d5

dart2js: Reduce assert helpers

Change-Id: Ic2ce0e485e3fd27b8f4e92371eb17a076d5192c1
Reviewed-on: https://dart-review.googlesource.com/c/92668
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Stephen Adams <sra@google.com>

pkg/compiler/lib/src/ssa/optimize.dart

diff --git a/pkg/compiler/lib/src/ssa/optimize.dart b/pkg/compiler/lib/src/ssa/optimize.dart
index 06be15a..007950f 100644
--- a/pkg/compiler/lib/src/ssa/optimize.dart
+++ b/pkg/compiler/lib/src/ssa/optimize.dart
@@ -1369,7 +1369,25 @@
           return argument;
         }
       }
+    } else if (element == commonElements.assertHelper ||
+        element == commonElements.assertTest) {
+      if (node.inputs.length == 1) {
+        HInstruction argument = node.inputs[0];
+        if (argument is HConstant) {
+          ConstantValue constant = argument.constant;
+          if (constant.isBool) {
+            bool value = constant.isTrue;
+            if (element == commonElements.assertTest) {
+              // `assertTest(argument)` effectively negates the argument.
+              return _graph.addConstantBool(!value, _closedWorld);
+            }
+            // `assertHelper(true)` is a no-op, other values throw.
+            if (value) return argument;
+          }
+        }
+      }
     }
+
     return node;
   }