diff --git a/compiler/forget/src/Inference/InferAliasForPhis.ts b/compiler/forget/src/Inference/InferAliasForPhis.ts
new file mode 100644
index 0000000000..0059cd3003
--- /dev/null
+++ b/compiler/forget/src/Inference/InferAliasForPhis.ts
@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+import { HIRFunction, Identifier } from "../HIR/HIR";
+import DisjointSet from "../Utils/DisjointSet";
+
+export function inferAliasForPhis(
+  func: HIRFunction,
+  aliases: DisjointSet<Identifier>
+) {
+  for (const [_, block] of func.body.blocks) {
+    for (const phi of block.phis) {
+      const isPhiMutatedAfterCreation: boolean =
+        phi.id.mutableRange.end >
+        (block.instructions.at(0)?.id ?? block.terminal.id);
+      if (isPhiMutatedAfterCreation) {
+        for (const [, operand] of phi.operands) {
+          aliases.union([phi.id, operand]);
+        }
+      }
+    }
+  }
+}
diff --git a/compiler/forget/src/Inference/InferMutableRanges.ts b/compiler/forget/src/Inference/InferMutableRanges.ts
index 0253fe2845..c5c168371f 100644
--- a/compiler/forget/src/Inference/InferMutableRanges.ts
+++ b/compiler/forget/src/Inference/InferMutableRanges.ts
@@ -7,6 +7,7 @@
 
 import { HIRFunction, Identifier } from "../HIR/HIR";
 import { inferAliases } from "./InferAlias";
+import { inferAliasForPhis } from "./InferAliasForPhis";
 import { inferAliasForStores } from "./InferAliasForStores";
 import { inferMutableLifetimes } from "./InferMutableLifetimes";
 import { inferMutableRangesForAlias } from "./InferMutableRangesForAlias";
@@ -27,6 +28,9 @@ export function inferMutableRanges(ir: HIRFunction) {
     // Update aliasing information of fields
     inferAliasForStores(ir, aliases);
 
+    // Update aliasing information of phis
+    inferAliasForPhis(ir, aliases);
+
     const nextAliases = aliases.canonicalize();
     if (areEqualMaps(prevAliases, nextAliases)) {
       break;
diff --git a/compiler/forget/src/Inference/InferMutableRangesForAlias.ts b/compiler/forget/src/Inference/InferMutableRangesForAlias.ts
index 95b96c8ef7..4de85bec4b 100644
--- a/compiler/forget/src/Inference/InferMutableRangesForAlias.ts
+++ b/compiler/forget/src/Inference/InferMutableRangesForAlias.ts
@@ -31,17 +31,4 @@ export function inferMutableRangesForAlias(
       }
     }
   }
-
-  for (const [_, block] of fn.body.blocks) {
-    for (const phi of block.phis) {
-      const isPhiMutatedAfterCreation: boolean =
-        phi.id.mutableRange.end >
-        (block.instructions.at(0)?.id ?? block.terminal.id);
-      if (isPhiMutatedAfterCreation) {
-        for (const [, operand] of phi.operands) {
-          aliases.union([phi.id, operand]);
-        }
-      }
-    }
-  }
 }