diff --git a/compiler/forget/src/HIR/PrintHIR.ts b/compiler/forget/src/HIR/PrintHIR.ts
index 32d4a3ead4..a8137ba25a 100644
--- a/compiler/forget/src/HIR/PrintHIR.ts
+++ b/compiler/forget/src/HIR/PrintHIR.ts
@@ -114,7 +114,7 @@ export function printInstruction(instr: ReactiveInstruction): string {
 function printPhi(phi: Phi): string {
   const items = [];
   items.push(printIdentifier(phi.id));
-  // items.push(printMutableRange(phi.id));
+  items.push(printMutableRange(phi.id));
   items.push(printType(phi.type));
   items.push(": phi(");
   const phis = [];
diff --git a/compiler/forget/src/SSA/LeaveSSA.ts b/compiler/forget/src/SSA/LeaveSSA.ts
index 14afaf59cd..532d84e8d9 100644
--- a/compiler/forget/src/SSA/LeaveSSA.ts
+++ b/compiler/forget/src/SSA/LeaveSSA.ts
@@ -174,15 +174,8 @@ export function leaveSSA(fn: HIRFunction) {
       }
 
       // all versions of the variable need to be remapped to the canonical id
-      // also extend the mutable range of the canonical id based on the min/max
-      // of the ranges of its operands
-      let start = canonicalId.mutableRange.start as number;
-      let end = canonicalId.mutableRange.end as number;
       for (const [, operand] of phi.operands) {
-        start = Math.min(start, operand.mutableRange.start);
-        end = Math.max(end, operand.mutableRange.end);
         reassignments.set(operand, canonicalId);
-
         if (operand.mutableRange.start < terminal.id) {
           invariant(
             initOperand === null,
@@ -191,8 +184,6 @@ export function leaveSSA(fn: HIRFunction) {
           initOperand = operand;
         }
       }
-      canonicalId.mutableRange.start = makeInstructionId(start);
-      canonicalId.mutableRange.end = makeInstructionId(end);
 
       // If there are no instructions in the block then there's just a terminal
       // node, which has no mutation, so that should be false.
@@ -203,6 +194,14 @@ export function leaveSSA(fn: HIRFunction) {
         phi.id.mutableRange.end >
         (phiBlock.instructions.at(0)?.id ?? phiBlock.terminal.id);
 
+      // If a phi is never mutated after creation, reset its mutable range to be itself
+      if (!isPhiMutatedAfterCreation) {
+        canonicalId.mutableRange.start = phiBlock.terminal.id;
+        canonicalId.mutableRange.end = makeInstructionId(
+          phiBlock.terminal.id + 1
+        );
+      }
+
       // If this phi id is the canonical id we need to generate a let binding for it
       // (otherwise, it means this phi merges into some other phi which already generated
       // a binding
diff --git a/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-possibly-mutable-arguments.expect.md b/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-possibly-mutable-arguments.expect.md
index 3e20cfff28..5c66dadd3e 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-possibly-mutable-arguments.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-possibly-mutable-arguments.expect.md
@@ -29,29 +29,19 @@ function Component(props) {
   const $ = React.unstable_useMemoCache();
   const cond = props.cond;
   const x = props.x;
-  const c_0 = $[0] !== cond;
-  const c_1 = $[1] !== x;
-  let a;
-  if (c_0 || c_1) {
-    a = undefined;
-    if (cond) {
-      const a$0 = x;
-      a = a$0;
-    } else {
-      let a$1;
-      if ($[3] === Symbol.for("react.memo_cache_sentinel")) {
-        a$1 = [];
-        $[3] = a$1;
-      } else {
-        a$1 = $[3];
-      }
-      a = a$1;
-    }
-    $[0] = cond;
-    $[1] = x;
-    $[2] = a;
+  let a = undefined;
+  if (cond) {
+    const a$0 = x;
+    a = a$0;
   } else {
-    a = $[2];
+    let a$1;
+    if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+      a$1 = [];
+      $[0] = a$1;
+    } else {
+      a$1 = $[0];
+    }
+    a = a$1;
   }
 
   useFreeze(a);
diff --git a/compiler/forget/src/__tests__/fixtures/hir/infer-phi-primitive.expect.md b/compiler/forget/src/__tests__/fixtures/hir/infer-phi-primitive.expect.md
index 8089a133a3..5c2a1044ae 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/infer-phi-primitive.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/infer-phi-primitive.expect.md
@@ -20,22 +20,13 @@ function foo(a, b) {
 
 ```javascript
 function foo(a, b) {
-  const $ = React.unstable_useMemoCache();
-  const c_0 = $[0] !== a;
-  let x;
-  if (c_0) {
-    x = undefined;
-    if (a) {
-      const x$0 = 1;
-      x = x$0;
-    } else {
-      const x$1 = 2;
-      x = x$1;
-    }
-    $[0] = a;
-    $[1] = x;
+  let x = undefined;
+  if (a) {
+    const x$0 = 1;
+    x = x$0;
   } else {
-    x = $[1];
+    const x$1 = 2;
+    x = x$1;
   }
 
   const y = x;
diff --git a/compiler/forget/src/__tests__/fixtures/hir/obj-literal-cached-in-if-else.expect.md b/compiler/forget/src/__tests__/fixtures/hir/obj-literal-cached-in-if-else.expect.md
index e3f4ed85c8..02a22b8c47 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/obj-literal-cached-in-if-else.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/obj-literal-cached-in-if-else.expect.md
@@ -20,39 +20,29 @@ function foo(a, b, c, d) {
 ```javascript
 function foo(a, b, c, d) {
   const $ = React.unstable_useMemoCache();
-  const c_0 = $[0] !== b;
-  const c_1 = $[1] !== c;
-  let x;
-  if (c_0 || c_1) {
-    x = undefined;
-    if (someVal) {
-      const c_3 = $[3] !== b;
-      let x$0;
-      if (c_3) {
-        x$0 = { b: b };
-        $[3] = b;
-        $[4] = x$0;
-      } else {
-        x$0 = $[4];
-      }
-      x = x$0;
+  let x = undefined;
+  if (someVal) {
+    const c_0 = $[0] !== b;
+    let x$0;
+    if (c_0) {
+      x$0 = { b: b };
+      $[0] = b;
+      $[1] = x$0;
     } else {
-      const c_5 = $[5] !== c;
-      let x$1;
-      if (c_5) {
-        x$1 = { c: c };
-        $[5] = c;
-        $[6] = x$1;
-      } else {
-        x$1 = $[6];
-      }
-      x = x$1;
+      x$0 = $[1];
     }
-    $[0] = b;
-    $[1] = c;
-    $[2] = x;
+    x = x$0;
   } else {
-    x = $[2];
+    const c_2 = $[2] !== c;
+    let x$1;
+    if (c_2) {
+      x$1 = { c: c };
+      $[2] = c;
+      $[3] = x$1;
+    } else {
+      x$1 = $[3];
+    }
+    x = x$1;
   }
   return x;
 }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/primitive-alias-mutate.expect.md b/compiler/forget/src/__tests__/fixtures/hir/primitive-alias-mutate.expect.md
index 448ab5ba68..0014449a79 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/primitive-alias-mutate.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/primitive-alias-mutate.expect.md
@@ -20,22 +20,13 @@ function component(a) {
 
 ```javascript
 function component(a) {
-  const $ = React.unstable_useMemoCache();
-  const c_0 = $[0] !== a;
-  let x;
-  if (c_0) {
-    x = undefined;
-    if (a) {
-      const x$0 = "bar";
-      x = x$0;
-    } else {
-      const x$1 = "baz";
-      x = x$1;
-    }
-    $[0] = a;
-    $[1] = x;
+  let x = undefined;
+  if (a) {
+    const x$0 = "bar";
+    x = x$0;
   } else {
-    x = $[1];
+    const x$1 = "baz";
+    x = x$1;
   }
 
   const y = x;
diff --git a/compiler/forget/src/__tests__/fixtures/hir/reassignment-conditional.expect.md b/compiler/forget/src/__tests__/fixtures/hir/reassignment-conditional.expect.md
index 5925eeeeca..eb87414d0c 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/reassignment-conditional.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/reassignment-conditional.expect.md
@@ -35,37 +35,27 @@ function Component(props) {
     x = $[1];
   }
   const y = x;
-  const c_2 = $[2] !== props.p1;
-  let x$0;
-  if (c_2) {
-    x$0 = x;
-    if (props.p1) {
-      let x$1;
-      if ($[4] === Symbol.for("react.memo_cache_sentinel")) {
-        x$1 = [];
-        $[4] = x$1;
-      } else {
-        x$1 = $[4];
-      }
-      x$0 = x$1;
+  let x$0 = x;
+  if (props.p1) {
+    let x$1;
+    if ($[2] === Symbol.for("react.memo_cache_sentinel")) {
+      x$1 = [];
+      $[2] = x$1;
+    } else {
+      x$1 = $[2];
     }
-    $[2] = props.p1;
-    $[3] = x$0;
-  } else {
-    x$0 = $[3];
+    x$0 = x$1;
   }
 
   y.push(props.p2);
-  const c_5 = $[5] !== x$0;
-  const c_6 = $[6] !== y;
+  const c_3 = $[3] !== y;
   let t0;
-  if (c_5 || c_6) {
+  if (c_3) {
     t0 = <Component x={x$0} y={y}></Component>;
-    $[5] = x$0;
-    $[6] = y;
-    $[7] = t0;
+    $[3] = y;
+    $[4] = t0;
   } else {
-    t0 = $[7];
+    t0 = $[4];
   }
   return t0;
 }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/reassignment-separate-scopes.expect.md b/compiler/forget/src/__tests__/fixtures/hir/reassignment-separate-scopes.expect.md
index 3fadaf0fcb..f65319c67a 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/reassignment-separate-scopes.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/reassignment-separate-scopes.expect.md
@@ -56,61 +56,49 @@ function foo(a, b, c) {
   } else {
     y = $[3];
   }
-  const c_4 = $[4] !== b;
-  const c_5 = $[5] !== c;
-  let x$0;
-  if (c_4 || c_5) {
-    x$0 = undefined;
-    bb3: switch (b) {
-      case 0: {
-        const c_7 = $[7] !== b;
-        let x$1;
-        if (c_7) {
-          x$1 = [];
-          x$1.push(b);
-          $[7] = b;
-          $[8] = x$1;
-        } else {
-          x$1 = $[8];
-        }
-        x$0 = x$1;
-        break bb3;
-      }
-      default: {
-        const c_9 = $[9] !== c;
-        let x$2;
-        if (c_9) {
-          x$2 = [];
-          x$2.push(c);
-          $[9] = c;
-          $[10] = x$2;
-        } else {
-          x$2 = $[10];
-        }
-        x$0 = x$2;
+  let x$0 = undefined;
+  bb3: switch (b) {
+    case 0: {
+      const c_4 = $[4] !== b;
+      let x$1;
+      if (c_4) {
+        x$1 = [];
+        x$1.push(b);
+        $[4] = b;
+        $[5] = x$1;
+      } else {
+        x$1 = $[5];
       }
+      x$0 = x$1;
+      break bb3;
+    }
+    default: {
+      const c_6 = $[6] !== c;
+      let x$2;
+      if (c_6) {
+        x$2 = [];
+        x$2.push(c);
+        $[6] = c;
+        $[7] = x$2;
+      } else {
+        x$2 = $[7];
+      }
+      x$0 = x$2;
     }
-    $[4] = b;
-    $[5] = c;
-    $[6] = x$0;
-  } else {
-    x$0 = $[6];
   }
-  const c_11 = $[11] !== y;
-  const c_12 = $[12] !== x$0;
+  const c_8 = $[8] !== y;
   let t0;
-  if (c_11 || c_12) {
+  if (c_8) {
     t0 = (
       <div>
         {y}
         {x$0}
       </div>
     );
-    $[11] = y;
-    $[12] = x$0;
-    $[13] = t0;
+    $[8] = y;
+    $[9] = t0;
   } else {
-    t0 = $[13];
+    t0 = $[9];
   }
   return t0;
 }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/ssa-leave-case.expect.md b/compiler/forget/src/__tests__/fixtures/hir/ssa-leave-case.expect.md
index 4c7225c6d8..ba26e228b8 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/ssa-leave-case.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/ssa-leave-case.expect.md
@@ -27,11 +27,10 @@ function Component(props) {
   const c_0 = $[0] !== props.p0;
   const c_1 = $[1] !== props.p1;
   let x;
-  let y$0;
   if (c_0 || c_1) {
     x = [];
     const y = undefined;
-    y$0 = y;
+    let y$0 = y;
     if (props.p0) {
       x.push(props.p1);
       const y$1 = x;
@@ -40,26 +39,22 @@ function Component(props) {
     $[0] = props.p0;
     $[1] = props.p1;
     $[2] = x;
-    $[3] = y$0;
   } else {
     x = $[2];
-    y$0 = $[3];
   }
-  const c_4 = $[4] !== x;
-  const c_5 = $[5] !== y$0;
+  const c_3 = $[3] !== x;
   let t0;
-  if (c_4 || c_5) {
+  if (c_3) {
     t0 = (
       <Component>
         {x}
         {y$0}
       </Component>
     );
-    $[4] = x;
-    $[5] = y$0;
-    $[6] = t0;
+    $[3] = x;
+    $[4] = t0;
   } else {
-    t0 = $[6];
+    t0 = $[4];
   }
   return t0;
 }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/ssa-nested-partial-phi.expect.md b/compiler/forget/src/__tests__/fixtures/hir/ssa-nested-partial-phi.expect.md
index 37ffd23bc5..f6c4b97fb7 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/ssa-nested-partial-phi.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/ssa-nested-partial-phi.expect.md
@@ -19,21 +19,12 @@ function foo(a, b, c) {
 
 ```javascript
 function foo(a, b, c) {
-  const $ = React.unstable_useMemoCache();
   const x = a;
   if (b) {
-    const c_0 = $[0] !== c;
-    let x$0;
-    if (c_0) {
-      x$0 = x;
-      if (c) {
-        const x$1 = c;
-        x$0 = x$1;
-      }
-      $[0] = c;
-      $[1] = x$0;
-    } else {
-      x$0 = $[1];
+    let x$0 = x;
+    if (c) {
+      const x$1 = c;
+      x$0 = x$1;
     }
     return x$0;
   }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/ssa-nested-partial-reassignment.expect.md b/compiler/forget/src/__tests__/fixtures/hir/ssa-nested-partial-reassignment.expect.md
index bb07e3f0b2..735903f228 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/ssa-nested-partial-reassignment.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/ssa-nested-partial-reassignment.expect.md
@@ -20,31 +20,16 @@ function foo(a, b, c, d, e) {
 
 ```javascript
 function foo(a, b, c, d, e) {
-  const $ = React.unstable_useMemoCache();
   const x = null;
-  const c_0 = $[0] !== a;
-  const c_1 = $[1] !== b;
-  const c_2 = $[2] !== c;
-  const c_3 = $[3] !== d;
-  let x$0;
-  if (c_0 || c_1 || c_2 || c_3) {
-    x$0 = x;
-    if (a) {
-      const x$1 = b;
-      x$0 = x$1;
-    } else {
-      if (c) {
-        const x$2 = d;
-        x$0 = x$2;
-      }
-    }
-    $[0] = a;
-    $[1] = b;
-    $[2] = c;
-    $[3] = d;
-    $[4] = x$0;
+  let x$0 = x;
+  if (a) {
+    const x$1 = b;
+    x$0 = x$1;
   } else {
-    x$0 = $[4];
+    if (c) {
+      const x$2 = d;
+      x$0 = x$2;
+    }
   }
   return x$0;
 }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/ssa-renaming.expect.md b/compiler/forget/src/__tests__/fixtures/hir/ssa-renaming.expect.md
index 01f3e8648a..8e9ec02af8 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/ssa-renaming.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/ssa-renaming.expect.md
@@ -30,29 +30,19 @@ function foo(props) {
   } else {
     x = $[1];
   }
-  const c_2 = $[2] !== props.cond;
-  const c_3 = $[3] !== props.foo;
-  let x$0;
-  if (c_2 || c_3) {
-    x$0 = x;
-    if (props.cond) {
-      const c_5 = $[5] !== props.foo;
-      let x$1;
-      if (c_5) {
-        x$1 = [];
-        x$1.push(props.foo);
-        $[5] = props.foo;
-        $[6] = x$1;
-      } else {
-        x$1 = $[6];
-      }
-      x$0 = x$1;
+  let x$0 = x;
+  if (props.cond) {
+    const c_2 = $[2] !== props.foo;
+    let x$1;
+    if (c_2) {
+      x$1 = [];
+      x$1.push(props.foo);
+      $[2] = props.foo;
+      $[3] = x$1;
+    } else {
+      x$1 = $[3];
     }
-    $[2] = props.cond;
-    $[3] = props.foo;
-    $[4] = x$0;
-  } else {
-    x$0 = $[4];
+    x$0 = x$1;
   }
   return x$0;
 }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/ssa-shadowing.expect.md b/compiler/forget/src/__tests__/fixtures/hir/ssa-shadowing.expect.md
index dc47c50bef..6e0b1b7f56 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/ssa-shadowing.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/ssa-shadowing.expect.md
@@ -23,23 +23,14 @@ function Foo(cond) {
 function log() {}
 
 function Foo(cond) {
-  const $ = React.unstable_useMemoCache();
   const str = "";
-  const c_0 = $[0] !== cond;
-  let str$0;
-  if (c_0) {
-    str$0 = str;
-    if (cond) {
-      const str_0 = "other test";
-      log(str_0);
-    } else {
-      const str$1 = "fallthrough test";
-      str$0 = str$1;
-    }
-    $[0] = cond;
-    $[1] = str$0;
+  let str$0 = str;
+  if (cond) {
+    const str_0 = "other test";
+    log(str_0);
   } else {
-    str$0 = $[1];
+    const str$1 = "fallthrough test";
+    str$0 = str$1;
   }
 
   log(str$0);
diff --git a/compiler/forget/src/__tests__/fixtures/hir/switch-non-final-default.expect.md b/compiler/forget/src/__tests__/fixtures/hir/switch-non-final-default.expect.md
index 9ddb49f74d..9fe7363ddb 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/switch-non-final-default.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/switch-non-final-default.expect.md
@@ -36,11 +36,10 @@ function Component(props) {
   const c_0 = $[0] !== props.p0;
   const c_1 = $[1] !== props.p2;
   let x;
-  let y$0;
   if (c_0 || c_1) {
     x = [];
     const y = undefined;
-    y$0 = y;
+    let y$0 = y;
     bb1: switch (props.p0) {
       case 1: {
         break bb1;
@@ -48,11 +47,11 @@ function Component(props) {
       case true: {
         x.push(props.p2);
         let y$1;
-        if ($[4] === Symbol.for("react.memo_cache_sentinel")) {
+        if ($[3] === Symbol.for("react.memo_cache_sentinel")) {
           y$1 = [];
-          $[4] = y$1;
+          $[3] = y$1;
         } else {
-          y$1 = $[4];
+          y$1 = $[3];
         }
         y$0 = y$1;
         break bb1;
@@ -68,31 +67,27 @@ function Component(props) {
     $[0] = props.p0;
     $[1] = props.p2;
     $[2] = x;
-    $[3] = y$0;
   } else {
     x = $[2];
-    y$0 = $[3];
   }
-  const c_5 = $[5] !== x;
+  const c_4 = $[4] !== x;
   let child;
-  if (c_5) {
+  if (c_4) {
     child = <Component data={x}></Component>;
-    $[5] = x;
-    $[6] = child;
+    $[4] = x;
+    $[5] = child;
   } else {
-    child = $[6];
+    child = $[5];
   }
   y$0.push(props.p4);
-  const c_7 = $[7] !== y$0;
-  const c_8 = $[8] !== child;
+  const c_6 = $[6] !== child;
   let t0;
-  if (c_7 || c_8) {
+  if (c_6) {
     t0 = <Component data={y$0}>{child}</Component>;
-    $[7] = y$0;
-    $[8] = child;
-    $[9] = t0;
+    $[6] = child;
+    $[7] = t0;
   } else {
-    t0 = $[9];
+    t0 = $[7];
   }
   return t0;
 }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/switch.expect.md b/compiler/forget/src/__tests__/fixtures/hir/switch.expect.md
index fa5f40ea80..52cac52421 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/switch.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/switch.expect.md
@@ -32,11 +32,10 @@ function Component(props) {
   const c_1 = $[1] !== props.p2;
   const c_2 = $[2] !== props.p3;
   let x;
-  let y$0;
   if (c_0 || c_1 || c_2) {
     x = [];
     const y = undefined;
-    y$0 = y;
+    let y$0 = y;
     switch (props.p0) {
       case true: {
         x.push(props.p2);
@@ -51,31 +50,27 @@ function Component(props) {
     $[1] = props.p2;
     $[2] = props.p3;
     $[3] = x;
-    $[4] = y$0;
   } else {
     x = $[3];
-    y$0 = $[4];
   }
-  const c_5 = $[5] !== x;
+  const c_4 = $[4] !== x;
   let child;
-  if (c_5) {
+  if (c_4) {
     child = <Component data={x}></Component>;
-    $[5] = x;
-    $[6] = child;
+    $[4] = x;
+    $[5] = child;
   } else {
-    child = $[6];
+    child = $[5];
   }
   y$0.push(props.p4);
-  const c_7 = $[7] !== y$0;
-  const c_8 = $[8] !== child;
+  const c_6 = $[6] !== child;
   let t0;
-  if (c_7 || c_8) {
+  if (c_6) {
     t0 = <Component data={y$0}>{child}</Component>;
-    $[7] = y$0;
-    $[8] = child;
-    $[9] = t0;
+    $[6] = child;
+    $[7] = t0;
   } else {
-    t0 = $[9];
+    t0 = $[7];
   }
   return t0;
 }