propagate ref nonnull state

Author: dcodeIO

src/flow.ts

@@ -70,6 +70,7 @@ import {
   getUnaryValue,
   getCallOperandAt,
   getCallOperandCount,
+  getRefIsNullValue,
   isConstZero,
   isConstNonZero
 } from "./module";
@@ -1049,6 +1050,10 @@ export class Flow {
         }
         break;
       }
+      case ExpressionId.RefIsNull: {
+        this.inheritNonnullIfFalse(getRefIsNullValue(expr), iff); // value == null -> value must have been null
+        break;
+      }
     }
   }
 
@@ -1140,6 +1145,10 @@ export class Flow {
         }
         break;
       }
+      case ExpressionId.RefIsNull: {
+        this.inheritNonnullIfTrue(getRefIsNullValue(expr), iff); // value == null -> value must have been non-null
+        break;
+      }
     }
   }
 

src/module.ts

@@ -3553,6 +3553,10 @@ export function getMemoryGrowDelta(expr: ExpressionRef): ExpressionRef {
   return binaryen._BinaryenMemoryGrowGetDelta(expr);
 }
 
+export function getRefIsNullValue(expr: ExpressionRef): ExpressionRef {
+  return binaryen._BinaryenRefIsNullGetValue(expr);
+}
+
 // functions
 
 export function getFunctionBody(func: FunctionRef): ExpressionRef {