Better bitwise and binary arithmetic when the left operand is known to be a number.

lib/compiler/implementation/ssa/codegen_helpers.dart

Index: lib/compiler/implementation/ssa/codegen_helpers.dart
diff --git a/lib/compiler/implementation/ssa/codegen_helpers.dart b/lib/compiler/implementation/ssa/codegen_helpers.dart
index 610c7455b9f31adf79835765a6caf778b0eaeb0c..f1b5fa7747187cd0ba3ef1213abebed835aec021 100644
--- a/lib/compiler/implementation/ssa/codegen_helpers.dart
+++ b/lib/compiler/implementation/ssa/codegen_helpers.dart
@@ -48,8 +48,13 @@ class SsaInstructionMerger extends HBaseVisitor {
   void visitTypeGuard(HTypeGuard instruction) {}
 
   void visitTypeConversion(HTypeConversion instruction) {
-    if (!instruction.checked) generateAtUseSite.add(instruction);
-    visitInstruction(instruction);
+    if (!instruction.isChecked()) {
+      generateAtUseSite.add(instruction);
+    } else if (instruction.isCheckedModeCheck()) {
+      // Checked mode checks compile to code that only use their input
+      // once, so we can safely visit them an try to merge the input.

[floitsch, 2012/06/19 11:15:58]

and

[kasperl, 2012/06/19 11:22:06]

Done.

+      visitInstruction(instruction);
+    }
   }
 
   void tryGenerateAtUseSite(HInstruction instruction) {