Fix for dart2js codegen issue 22487

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

Index: pkg/compiler/lib/src/ssa/types_propagation.dart
diff --git a/pkg/compiler/lib/src/ssa/types_propagation.dart b/pkg/compiler/lib/src/ssa/types_propagation.dart
index 4f3e7eec8f94605553b1d5fb0e39d066f961fe10..e16641c2ca50137914c59d0b625d9b5a83800ad7 100644
--- a/pkg/compiler/lib/src/ssa/types_propagation.dart
+++ b/pkg/compiler/lib/src/ssa/types_propagation.dart
@@ -127,6 +127,11 @@ class SsaTypePropagator extends HBaseVisitor implements OptimizationPhase {
     return checkPositiveInteger(instruction);
   }
 
+  TypeMask visitDivide(HDivide instruction) {
+    // Always double, as initialized.
+    return instruction.instructionType;
+  }
+
   TypeMask visitNegate(HNegate instruction) {
     HInstruction operand = instruction.operand;
     // We have integer subclasses that represent ranges, so widen any int