diff --git a/compiler/forget/src/__tests__/fixtures/hir/call.expect.md b/compiler/forget/src/__tests__/fixtures/hir/call.expect.md
index d880d599d0..e4d0dcf1e0 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/call.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/call.expect.md
@@ -34,28 +34,28 @@ function foo$0() {
 
 ```
 bb0:
-  Const mutate a$2 = Array []
-  Const mutate b$3 = Object {  }
-  Call mutate foo$4(mutate a$2, mutate b$3)
-  Const mutate $6 = "div"
-  Let mutate _$5 = JSX <read $6 a={freeze a$2} ></read $6>
-  Call mutate foo$4(mutate b$3)
-  Const mutate $7 = "div"
-  Const mutate $8 = JSX <read $7 a={read a$2} b={freeze b$3} ></read $7>
-  Return read $8
+  Const mutate a$10 = Array []
+  Const mutate b$11 = Object {  }
+  Call mutate foo$4(mutate a$10, mutate b$11)
+  Const mutate $12 = "div"
+  Let mutate _$13 = JSX <read $12 a={freeze a$10} ></read $12>
+  Call mutate foo$4(mutate b$11)
+  Const mutate $14 = "div"
+  Const mutate $15 = JSX <read $14 a={read a$10} b={freeze b$11} ></read $14>
+  Return read $15
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = [];
-  const b$3 = {};
-  foo$4(a$2, b$3);
-  let _$5 = <div a={a$2}></div>;
+function Component$0(props$9) {
+  const a$10 = [];
+  const b$11 = {};
+  foo$4(a$10, b$11);
+  let _$13 = <div a={a$10}></div>;
 
-  foo$4(b$3);
-  return <div a={a$2} b={b$3}></div>;
+  foo$4(b$11);
+  return <div a={a$10} b={b$11}></div>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/component.expect.md b/compiler/forget/src/__tests__/fixtures/hir/component.expect.md
index 84c9732330..dacfe47037 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/component.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/component.expect.md
@@ -35,63 +35,75 @@ function Component(props) {
 
 ```
 bb0:
-  Const mutate items$2 = read props$1.items
-  Const mutate maxItems$3 = read props$1.maxItems
-  Const mutate renderedItems$4 = Array []
-  Const mutate seen$5 = New mutate Set$6()
-  Const mutate $9 = 0
-  Const mutate max$7 = Call mutate Math$8.max(read $9, read maxItems$3)
+  Const mutate items$27 = read props$26.items
+  Const mutate maxItems$28 = read props$26.maxItems
+  Const mutate renderedItems$29 = Array []
+  Const mutate seen$30 = New mutate Set$6()
+  Const mutate $31 = 0
+  Const mutate max$32 = Call mutate Math$8.max(read $31, read maxItems$28)
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb4 bb7
-  If (read items$2) then:bb3 else:bb2
+  items$33: phi(bb0: items$27, bb4: items$50, bb7: items$50)
+  item$35: phi(bb0: item$10, bb4: item$42, bb7: item$42)
+  seen$38: phi(bb0: seen$30, bb4: seen$41, bb7: seen$41)
+  renderedItems$46: phi(bb0: renderedItems$29, bb4: renderedItems$45, bb7: renderedItems$45)
+  max$48: phi(bb0: max$32, bb4: max$47, bb7: max$47)
+  If (read items$33) then:bb3 else:bb2
 bb3:
   predecessor blocks: bb1
-  Const mutate $11 = null
-  Const mutate $12 = Binary read item$10 == read $11
-  If (read $12) then:bb8 else:bb9
+  Const mutate $34 = null
+  Const mutate $36 = Binary read item$35 == read $34
+  If (read $36) then:bb8 else:bb9
 bb8:
   predecessor blocks: bb3
-  Const mutate $13 = read $12
+  Const mutate $37 = read $36
   Goto bb7
 bb9:
   predecessor blocks: bb3
-  Const mutate $13 = Call mutate seen$5.has(mutate item$10)
+  Const mutate $39 = Call mutate seen$38.has(mutate item$35)
   Goto bb7
 bb7:
   predecessor blocks: bb9 bb8
-  If (read $13) then:bb1 else:bb4
+  $40: phi(bb9: $39, bb8: $37)
+  seen$41: phi(bb9: seen$38, bb8: seen$38)
+  item$42: phi(bb9: item$35, bb8: item$35)
+  renderedItems$45: phi(bb9: renderedItems$46, bb8: renderedItems$46)
+  max$47: phi(bb9: max$48, bb8: max$48)
+  items$50: phi(bb9: items$33, bb8: items$33)
+  If (read $40) then:bb1 else:bb4
 bb4:
   predecessor blocks: bb7
-  Call mutate seen$5.add(mutate item$10)
-  Const mutate $14 = "div"
-  Const mutate $15 = JSX <read $14>{read item$10}</read $14>
-  Call mutate renderedItems$4.push(read $15)
-  Const mutate $16 = Binary read renderedItems$4.length >= read max$7
-  If (read $16) then:bb2 else:bb1
+  Call mutate seen$41.add(mutate item$42)
+  Const mutate $43 = "div"
+  Const mutate $44 = JSX <read $43>{read item$42}</read $43>
+  Call mutate renderedItems$45.push(read $44)
+  Const mutate $49 = Binary read renderedItems$45.length >= read max$47
+  If (read $49) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb1 bb4
-  Const mutate count$17 = read renderedItems$4.length
-  Const mutate $18 = "div"
-  Const mutate $19 = "\n      "
-  Const mutate $20 = "h1"
-  Const mutate $21 = " Items"
-  Const mutate $22 = JSX <read $20>{freeze count$17}{read $21}</read $20>
-  Const mutate $23 = "\n      "
-  Const mutate $24 = "\n    "
-  Const mutate $25 = JSX <read $18>{read $19}{read $22}{read $23}{freeze renderedItems$4}{read $24}</read $18>
-  Return read $25
+  renderedItems$51: phi(bb1: renderedItems$46, bb4: renderedItems$45)
+  Const mutate count$52 = read renderedItems$51.length
+  Const mutate $53 = "div"
+  Const mutate $54 = "\n      "
+  Const mutate $55 = "h1"
+  Const mutate $56 = " Items"
+  Const mutate $57 = JSX <read $55>{freeze count$52}{read $56}</read $55>
+  Const mutate $58 = "\n      "
+  Const mutate $59 = "\n    "
+  Const mutate $60 = JSX <read $53>{read $54}{read $57}{read $58}{freeze renderedItems$51}{read $59}</read $53>
+  Return read $60
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const items$2 = props$1.items;
-  const maxItems$3 = props$1.maxItems;
-  const renderedItems$4 = [];
-  const seen$5 = new Set$6();
-  const max$7 = Math$8.max(0, maxItems$3);
+function Component$0(props$26) {
+  const items$27 = props$26.items;
+  const maxItems$28 = props$26.maxItems;
+  const renderedItems$29 = [];
+  const seen$30 = new Set$6();
+  const max$32 = Math$8.max(0, maxItems$28);
   ("<<TODO: handle complex control flow in codegen>>");
 }
 
diff --git a/compiler/forget/src/__tests__/fixtures/hir/conditional-break.expect.md b/compiler/forget/src/__tests__/fixtures/hir/conditional-break.expect.md
index d79b048ebb..dad55cd5e6 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/conditional-break.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/conditional-break.expect.md
@@ -78,31 +78,31 @@ function Component(props) {
 
 ```
 bb0:
-  Const mutate a_DEBUG$2 = Array []
-  Call mutate a_DEBUG$2.push(read props$1.a)
-  If (read props$1.b) then:bb2 else:bb1
+  Const mutate a_DEBUG$5 = Array []
+  Call mutate a_DEBUG$5.push(read props$4.a)
+  If (read props$4.b) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Const mutate $3 = null
-  Return read $3
+  Const mutate $6 = null
+  Return read $6
 bb1:
   predecessor blocks: bb0
-  Call mutate a_DEBUG$2.push(read props$1.d)
-  Return freeze a_DEBUG$2
+  Call mutate a_DEBUG$5.push(read props$4.d)
+  Return freeze a_DEBUG$5
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a_DEBUG$2 = [];
-  a_DEBUG$2.push(props$1.a);
-  if (props$1.b) {
+function Component$0(props$4) {
+  const a_DEBUG$5 = [];
+  a_DEBUG$5.push(props$4.a);
+  if (props$4.b) {
     return null;
   }
 
-  a_DEBUG$2.push(props$1.d);
-  return a_DEBUG$2;
+  a_DEBUG$5.push(props$4.d);
+  return a_DEBUG$5;
 }
 
 ```
@@ -110,32 +110,34 @@ function Component$0(props$1) {
 
 ```
 bb0:
-  Const mutate a$2 = Array []
-  Call mutate a$2.push(read props$1.a)
-  If (read props$1.b) then:bb2 else:bb1
+  Const mutate a$4 = Array []
+  Call mutate a$4.push(read props$3.a)
+  If (read props$3.b) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Call mutate a$2.push(read props$1.c)
+  Call mutate a$4.push(read props$3.c)
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb2
-  Call mutate a$2.push(read props$1.d)
-  Return freeze a$2
+  a$5: phi(bb0: a$4, bb2: a$4)
+  props$6: phi(bb0: props$3, bb2: props$3)
+  Call mutate a$5.push(read props$6.d)
+  Return freeze a$5
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = [];
-  a$2.push(props$1.a);
-  if (props$1.b) {
-    a$2.push(props$1.c);
+function Component$0(props$3) {
+  const a$4 = [];
+  a$4.push(props$3.a);
+  if (props$3.b) {
+    a$4.push(props$3.c);
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  a$2.push(props$1.d);
-  return a$2;
+  a$5.push(props$6.d);
+  return a$5;
 }
 
 ```
@@ -143,33 +145,33 @@ function Component$0(props$1) {
 
 ```
 bb0:
-  Const mutate a$2 = Array []
-  Call mutate a$2.push(read props$1.a)
-  If (read props$1.b) then:bb2 else:bb1
+  Const mutate a$5 = Array []
+  Call mutate a$5.push(read props$4.a)
+  If (read props$4.b) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Call mutate a$2.push(read props$1.c)
-  Const mutate $3 = null
-  Return read $3
+  Call mutate a$5.push(read props$4.c)
+  Const mutate $6 = null
+  Return read $6
 bb1:
   predecessor blocks: bb0
-  Call mutate a$2.push(read props$1.d)
-  Return freeze a$2
+  Call mutate a$5.push(read props$4.d)
+  Return freeze a$5
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = [];
-  a$2.push(props$1.a);
-  if (props$1.b) {
-    a$2.push(props$1.c);
+function Component$0(props$4) {
+  const a$5 = [];
+  a$5.push(props$4.a);
+  if (props$4.b) {
+    a$5.push(props$4.c);
     return null;
   }
 
-  a$2.push(props$1.d);
-  return a$2;
+  a$5.push(props$4.d);
+  return a$5;
 }
 
 ```
@@ -177,32 +179,32 @@ function Component$0(props$1) {
 
 ```
 bb0:
-  Const mutate a$2 = Array []
-  Call mutate a$2.push(read props$1.a)
-  If (read props$1.b) then:bb2 else:bb1
+  Const mutate a$4 = Array []
+  Call mutate a$4.push(read props$3.a)
+  If (read props$3.b) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Call mutate a$2.push(read props$1.c)
-  Return freeze a$2
+  Call mutate a$4.push(read props$3.c)
+  Return freeze a$4
 bb1:
   predecessor blocks: bb0
-  Call mutate a$2.push(read props$1.d)
-  Return freeze a$2
+  Call mutate a$4.push(read props$3.d)
+  Return freeze a$4
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = [];
-  a$2.push(props$1.a);
-  if (props$1.b) {
-    a$2.push(props$1.c);
-    return a$2;
+function Component$0(props$3) {
+  const a$4 = [];
+  a$4.push(props$3.a);
+  if (props$3.b) {
+    a$4.push(props$3.c);
+    return a$4;
   }
 
-  a$2.push(props$1.d);
-  return a$2;
+  a$4.push(props$3.d);
+  return a$4;
 }
 
 ```
@@ -210,31 +212,33 @@ function Component$0(props$1) {
 
 ```
 bb0:
-  Const mutate a$2 = Array []
-  Call mutate a$2.push(read props$1.a)
-  If (read props$1.b) then:bb1 else:bb2
+  Const mutate a$4 = Array []
+  Call mutate a$4.push(read props$3.a)
+  If (read props$3.b) then:bb1 else:bb2
 bb2:
   predecessor blocks: bb0
-  Call mutate a$2.push(read props$1.c)
+  Call mutate a$4.push(read props$3.c)
   Goto bb1
 bb1:
   predecessor blocks: bb2 bb0
-  Call mutate a$2.push(read props$1.d)
-  Return freeze a$2
+  a$5: phi(bb2: a$4, bb0: a$4)
+  props$6: phi(bb2: props$3, bb0: props$3)
+  Call mutate a$5.push(read props$6.d)
+  Return freeze a$5
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = [];
-  a$2.push(props$1.a);
-  if (props$1.b) {
-    a$2.push(props$1.d);
-    return a$2;
+function Component$0(props$3) {
+  const a$4 = [];
+  a$4.push(props$3.a);
+  if (props$3.b) {
+    a$5.push(props$6.d);
+    return a$5;
   }
 
-  a$2.push(props$1.c);
+  a$4.push(props$3.c);
   ("<<TODO: handle complex control flow in codegen>>");
 }
 
diff --git a/compiler/forget/src/__tests__/fixtures/hir/conditional-on-mutable.expect.md b/compiler/forget/src/__tests__/fixtures/hir/conditional-on-mutable.expect.md
index 1ea6a4364e..00809fd0d8 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/conditional-on-mutable.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/conditional-on-mutable.expect.md
@@ -67,43 +67,50 @@ function mayMutate() {}
 
 ```
 bb0:
-  Const mutate a$2 = Array []
-  Const mutate b$3 = Array []
-  If (read b$3) then:bb2 else:bb1
+  Const mutate a$7 = Array []
+  Const mutate b$8 = Array []
+  If (read b$8) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Call mutate a$2.push(read props$1.p0)
+  Call mutate a$7.push(read props$6.p0)
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb2
-  If (read props$1.p1) then:bb4 else:bb3
+  props$9: phi(bb0: props$6, bb2: props$6)
+  b$10: phi(bb0: b$8, bb2: b$8)
+  Foo$12: phi(bb0: Foo$4, bb2: Foo$4)
+  a$14: phi(bb0: a$7, bb2: a$7)
+  If (read props$9.p1) then:bb4 else:bb3
 bb4:
   predecessor blocks: bb1
-  Call mutate b$3.push(read props$1.p2)
+  Call mutate b$10.push(read props$9.p2)
   Goto bb3
 bb3:
   predecessor blocks: bb1 bb4
-  Const mutate $5 = JSX <read Foo$4 a={freeze a$2} b={freeze b$3} ></read Foo$4>
-  Return read $5
+  Foo$11: phi(bb1: Foo$12, bb4: Foo$12)
+  a$13: phi(bb1: a$14, bb4: a$14)
+  b$15: phi(bb1: b$10, bb4: b$10)
+  Const mutate $16 = JSX <read Foo$11 a={freeze a$13} b={freeze b$15} ></read Foo$11>
+  Return read $16
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = [];
-  const b$3 = [];
-  if (b$3) {
-    a$2.push(props$1.p0);
+function Component$0(props$6) {
+  const a$7 = [];
+  const b$8 = [];
+  if (b$8) {
+    a$7.push(props$6.p0);
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  if (props$1.p1) {
-    b$3.push(props$1.p2);
+  if (props$9.p1) {
+    b$10.push(props$9.p2);
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  return <Foo$4 a={a$2} b={b$3}></Foo$4>;
+  return <Foo$11 a={a$13} b={b$15}></Foo$11>;
 }
 
 ```
@@ -111,44 +118,51 @@ function Component$0(props$1) {
 
 ```
 bb0:
-  Const mutate a$2 = Array []
-  Const mutate b$3 = Array []
-  Const mutate $5 = Call mutate mayMutate$4(mutate b$3)
-  If (read $5) then:bb2 else:bb1
+  Const mutate a$9 = Array []
+  Const mutate b$10 = Array []
+  Const mutate $11 = Call mutate mayMutate$4(mutate b$10)
+  If (read $11) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Call mutate a$2.push(read props$1.p0)
+  Call mutate a$9.push(read props$8.p0)
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb2
-  If (read props$1.p1) then:bb4 else:bb3
+  props$12: phi(bb0: props$8, bb2: props$8)
+  b$13: phi(bb0: b$10, bb2: b$10)
+  Foo$15: phi(bb0: Foo$6, bb2: Foo$6)
+  a$17: phi(bb0: a$9, bb2: a$9)
+  If (read props$12.p1) then:bb4 else:bb3
 bb4:
   predecessor blocks: bb1
-  Call mutate b$3.push(read props$1.p2)
+  Call mutate b$13.push(read props$12.p2)
   Goto bb3
 bb3:
   predecessor blocks: bb1 bb4
-  Const mutate $7 = JSX <read Foo$6 a={freeze a$2} b={freeze b$3} ></read Foo$6>
-  Return read $7
+  Foo$14: phi(bb1: Foo$15, bb4: Foo$15)
+  a$16: phi(bb1: a$17, bb4: a$17)
+  b$18: phi(bb1: b$13, bb4: b$13)
+  Const mutate $19 = JSX <read Foo$14 a={freeze a$16} b={freeze b$18} ></read Foo$14>
+  Return read $19
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = [];
-  const b$3 = [];
-  if (mayMutate$4(b$3)) {
-    a$2.push(props$1.p0);
+function Component$0(props$8) {
+  const a$9 = [];
+  const b$10 = [];
+  if (mayMutate$4(b$10)) {
+    a$9.push(props$8.p0);
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  if (props$1.p1) {
-    b$3.push(props$1.p2);
+  if (props$12.p1) {
+    b$13.push(props$12.p2);
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  return <Foo$6 a={a$2} b={b$3}></Foo$6>;
+  return <Foo$14 a={a$16} b={b$18}></Foo$14>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/constructor.expect.md b/compiler/forget/src/__tests__/fixtures/hir/constructor.expect.md
index e331c900b0..6b79bee31d 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/constructor.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/constructor.expect.md
@@ -34,28 +34,28 @@ function Foo$0() {
 
 ```
 bb0:
-  Const mutate a$2 = Array []
-  Const mutate b$3 = Object {  }
-  New mutate Foo$4(mutate a$2, mutate b$3)
-  Const mutate $6 = "div"
-  Let mutate _$5 = JSX <read $6 a={freeze a$2} ></read $6>
-  New mutate Foo$4(mutate b$3)
-  Const mutate $7 = "div"
-  Const mutate $8 = JSX <read $7 a={read a$2} b={freeze b$3} ></read $7>
-  Return read $8
+  Const mutate a$10 = Array []
+  Const mutate b$11 = Object {  }
+  New mutate Foo$4(mutate a$10, mutate b$11)
+  Const mutate $12 = "div"
+  Let mutate _$13 = JSX <read $12 a={freeze a$10} ></read $12>
+  New mutate Foo$4(mutate b$11)
+  Const mutate $14 = "div"
+  Const mutate $15 = JSX <read $14 a={read a$10} b={freeze b$11} ></read $14>
+  Return read $15
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = [];
-  const b$3 = {};
-  new Foo$4(a$2, b$3);
-  let _$5 = <div a={a$2}></div>;
+function Component$0(props$9) {
+  const a$10 = [];
+  const b$11 = {};
+  new Foo$4(a$10, b$11);
+  let _$13 = <div a={a$10}></div>;
 
-  new Foo$4(b$3);
-  return <div a={a$2} b={b$3}></div>;
+  new Foo$4(b$11);
+  return <div a={a$10} b={b$11}></div>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/frozen-after-alias.expect.md b/compiler/forget/src/__tests__/fixtures/hir/frozen-after-alias.expect.md
index a947dd245f..bf745e9e4e 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/frozen-after-alias.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/frozen-after-alias.expect.md
@@ -18,10 +18,10 @@ function foo(x) {}
 
 ```
 bb0:
-  Const mutate a$1 = Array []
-  Const mutate b$2 = read a$1
-  Call read useFreeze$3(freeze a$1)
-  Call mutate foo$4(read b$2)
+  Const mutate a$5 = Array []
+  Const mutate b$6 = read a$5
+  Call read useFreeze$3(freeze a$5)
+  Call mutate foo$4(read b$6)
   Return
 ```
 
@@ -29,10 +29,10 @@ bb0:
 
 ```javascript
 function Component$0() {
-  const a$1 = [];
-  const b$2 = a$1;
-  useFreeze$3(a$1);
-  foo$4(b$2);
+  const a$5 = [];
+  const b$6 = a$5;
+  useFreeze$3(a$5);
+  foo$4(b$6);
   return;
 }
 
@@ -62,7 +62,7 @@ bb0:
 ## Code
 
 ```javascript
-function foo$0(x$1) {
+function foo$0(x$2) {
   return;
 }
 
diff --git a/compiler/forget/src/__tests__/fixtures/hir/hook-call.expect.md b/compiler/forget/src/__tests__/fixtures/hir/hook-call.expect.md
index a393dcc700..12d7dc54fd 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/hook-call.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/hook-call.expect.md
@@ -53,27 +53,27 @@ function foo$0() {
 
 ```
 bb0:
-  Const mutate x$2 = Array []
-  Const mutate y$3 = Call read useFreeze$4(freeze x$2)
-  Call mutate foo$5(read y$3, read x$2)
-  Const mutate $6 = "\n      "
-  Const mutate $7 = "\n      "
-  Const mutate $8 = "\n    "
-  Const mutate $9 = JSX <read Component$0>{read $6}{read x$2}{read $7}{read y$3}{read $8}</read Component$0>
-  Return read $9
+  Const mutate x$11 = Array []
+  Const mutate y$12 = Call read useFreeze$4(freeze x$11)
+  Call mutate foo$5(read y$12, read x$11)
+  Const mutate $13 = "\n      "
+  Const mutate $14 = "\n      "
+  Const mutate $15 = "\n    "
+  Const mutate $16 = JSX <read Component$0>{read $13}{read x$11}{read $14}{read y$12}{read $15}</read Component$0>
+  Return read $16
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const x$2 = [];
-  const y$3 = useFreeze$4(x$2);
-  foo$5(y$3, x$2);
+function Component$0(props$10) {
+  const x$11 = [];
+  const y$12 = useFreeze$4(x$11);
+  foo$5(y$12, x$11);
   return (
     <Component$0>
-      {x$2}
-      {y$3}
+      {x$11}
+      {y$12}
     </Component$0>
   );
 }
diff --git a/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-arguments.expect.md b/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-arguments.expect.md
index c3fb1cd885..f5e9158fc0 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-arguments.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/hooks-freeze-arguments.expect.md
@@ -19,22 +19,22 @@ function call(x) {}
 
 ```
 bb0:
-  Const mutate a$1 = Array []
-  Call read useFreeze$2(freeze a$1)
-  Call read useFreeze$2(read a$1)
-  Call mutate call$3(read a$1)
-  Return read a$1
+  Const mutate a$4 = Array []
+  Call read useFreeze$2(freeze a$4)
+  Call read useFreeze$2(read a$4)
+  Call mutate call$3(read a$4)
+  Return read a$4
 ```
 
 ## Code
 
 ```javascript
 function Component$0() {
-  const a$1 = [];
-  useFreeze$2(a$1);
-  useFreeze$2(a$1);
-  call$3(a$1);
-  return a$1;
+  const a$4 = [];
+  useFreeze$2(a$4);
+  useFreeze$2(a$4);
+  call$3(a$4);
+  return a$4;
 }
 
 ```
@@ -48,7 +48,7 @@ bb0:
 ## Code
 
 ```javascript
-function useFreeze$0(x$1) {
+function useFreeze$0(x$2) {
   return;
 }
 
@@ -63,7 +63,7 @@ bb0:
 ## Code
 
 ```javascript
-function call$0(x$1) {
+function call$0(x$2) {
   return;
 }
 
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 52de83c92d..0394ddf0ed 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
@@ -26,45 +26,48 @@ function call(x) {}
 
 ```
 bb0:
-  Const mutate cond$2 = read props$1.cond
-  Const mutate x$3 = read props$1.x
-  Let mutate a$4 = undefined
-  If (read cond$2) then:bb2 else:bb3
+  Const mutate cond$8 = read props$7.cond
+  Const mutate x$9 = read props$7.x
+  Let mutate a$10 = undefined
+  If (read cond$8) then:bb2 else:bb3
 bb2:
   predecessor blocks: bb0
-  Reassign mutate a$4 = read x$3
+  Reassign mutate a$11 = read x$9
   Goto bb1
 bb3:
   predecessor blocks: bb0
-  Reassign mutate a$4 = Array []
+  Reassign mutate a$12 = Array []
   Goto bb1
 bb1:
   predecessor blocks: bb3 bb2
-  Call read useFreeze$5(freeze a$4)
-  Call read useFreeze$5(read a$4)
-  Call mutate call$6(read a$4)
-  Return read a$4
+  useFreeze$13: phi(bb3: useFreeze$5, bb2: useFreeze$5)
+  a$14: phi(bb3: a$12, bb2: a$11)
+  call$15: phi(bb3: call$6, bb2: call$6)
+  Call read useFreeze$13(freeze a$14)
+  Call read useFreeze$13(read a$14)
+  Call mutate call$15(read a$14)
+  Return read a$14
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const cond$2 = props$1.cond;
-  const x$3 = props$1.x;
-  let a$4 = undefined;
-  if (cond$2) {
-    a$4 = x$3;
+function Component$0(props$7) {
+  const cond$8 = props$7.cond;
+  const x$9 = props$7.x;
+  let a$10 = undefined;
+  if (cond$8) {
+    a$11 = x$9;
     ("<<TODO: handle complex control flow in codegen>>");
   } else {
-    a$4 = [];
+    a$12 = [];
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  useFreeze$5(a$4);
-  useFreeze$5(a$4);
-  call$6(a$4);
-  return a$4;
+  useFreeze$13(a$14);
+  useFreeze$13(a$14);
+  call$15(a$14);
+  return a$14;
 }
 
 ```
@@ -78,7 +81,7 @@ bb0:
 ## Code
 
 ```javascript
-function useFreeze$0(x$1) {
+function useFreeze$0(x$2) {
   return;
 }
 
@@ -93,7 +96,7 @@ bb0:
 ## Code
 
 ```javascript
-function call$0(x$1) {
+function call$0(x$2) {
   return;
 }
 
diff --git a/compiler/forget/src/__tests__/fixtures/hir/independent-across-if.expect.md b/compiler/forget/src/__tests__/fixtures/hir/independent-across-if.expect.md
index 3dce042ea2..2537b2c99a 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/independent-across-if.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/independent-across-if.expect.md
@@ -97,33 +97,36 @@ function Foo$0() {
 
 ```
 bb0:
-  Const mutate a$2 = Call mutate compute$3(read props$1.a)
-  Const mutate b$4 = Call mutate compute$3(read props$1.b)
-  If (read props$1.c) then:bb2 else:bb1
+  Const mutate a$9 = Call mutate compute$3(read props$8.a)
+  Const mutate b$10 = Call mutate compute$3(read props$8.b)
+  If (read props$8.c) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Call mutate mutate$5(mutate a$2)
-  Call mutate mutate$5(mutate b$4)
+  Call mutate mutate$5(mutate a$9)
+  Call mutate mutate$5(mutate b$10)
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb2
-  Const mutate $7 = JSX <read Foo$6 a={freeze a$2} b={freeze b$4} ></read Foo$6>
-  Return read $7
+  Foo$11: phi(bb0: Foo$6, bb2: Foo$6)
+  a$12: phi(bb0: a$9, bb2: a$9)
+  b$13: phi(bb0: b$10, bb2: b$10)
+  Const mutate $14 = JSX <read Foo$11 a={freeze a$12} b={freeze b$13} ></read Foo$11>
+  Return read $14
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = compute$3(props$1.a);
-  const b$4 = compute$3(props$1.b);
-  if (props$1.c) {
-    mutate$5(a$2);
-    mutate$5(b$4);
+function Component$0(props$8) {
+  const a$9 = compute$3(props$8.a);
+  const b$10 = compute$3(props$8.b);
+  if (props$8.c) {
+    mutate$5(a$9);
+    mutate$5(b$10);
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  return <Foo$6 a={a$2} b={b$4}></Foo$6>;
+  return <Foo$11 a={a$12} b={b$13}></Foo$11>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/independent.expect.md b/compiler/forget/src/__tests__/fixtures/hir/independent.expect.md
index 6f89c6c44a..2292bc702c 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/independent.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/independent.expect.md
@@ -28,19 +28,19 @@ function Foo() {}
 
 ```
 bb0:
-  Const mutate a$2 = Call mutate compute$3(read props$1.a)
-  Const mutate b$4 = Call mutate compute$3(read props$1.b)
-  Const mutate $6 = JSX <read Foo$5 a={freeze a$2} b={freeze b$4} ></read Foo$5>
-  Return read $6
+  Const mutate a$8 = Call mutate compute$3(read props$7.a)
+  Const mutate b$9 = Call mutate compute$3(read props$7.b)
+  Const mutate $10 = JSX <read Foo$5 a={freeze a$8} b={freeze b$9} ></read Foo$5>
+  Return read $10
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = compute$3(props$1.a);
-  const b$4 = compute$3(props$1.b);
-  return <Foo$5 a={a$2} b={b$4}></Foo$5>;
+function Component$0(props$7) {
+  const a$8 = compute$3(props$7.a);
+  const b$9 = compute$3(props$7.b);
+  return <Foo$5 a={a$8} b={b$9}></Foo$5>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/interdependent-across-if.expect.md b/compiler/forget/src/__tests__/fixtures/hir/interdependent-across-if.expect.md
index 318328ece3..f0b150d952 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/interdependent-across-if.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/interdependent-across-if.expect.md
@@ -76,31 +76,34 @@ function Foo$0() {
 
 ```
 bb0:
-  Const mutate a$2 = Call mutate compute$3(read props$1.a)
-  Const mutate b$4 = Call mutate compute$3(read props$1.b)
-  If (read props$1.c) then:bb2 else:bb1
+  Const mutate a$9 = Call mutate compute$3(read props$8.a)
+  Const mutate b$10 = Call mutate compute$3(read props$8.b)
+  If (read props$8.c) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Call mutate foo$5(mutate a$2, mutate b$4)
+  Call mutate foo$5(mutate a$9, mutate b$10)
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb2
-  Const mutate $7 = JSX <read Foo$6 a={freeze a$2} b={freeze b$4} ></read Foo$6>
-  Return read $7
+  Foo$11: phi(bb0: Foo$6, bb2: Foo$6)
+  a$12: phi(bb0: a$9, bb2: a$9)
+  b$13: phi(bb0: b$10, bb2: b$10)
+  Const mutate $14 = JSX <read Foo$11 a={freeze a$12} b={freeze b$13} ></read Foo$11>
+  Return read $14
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = compute$3(props$1.a);
-  const b$4 = compute$3(props$1.b);
-  if (props$1.c) {
-    foo$5(a$2, b$4);
+function Component$0(props$8) {
+  const a$9 = compute$3(props$8.a);
+  const b$10 = compute$3(props$8.b);
+  if (props$8.c) {
+    foo$5(a$9, b$10);
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  return <Foo$6 a={a$2} b={b$4}></Foo$6>;
+  return <Foo$11 a={a$12} b={b$13}></Foo$11>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/interdependent.expect.md b/compiler/forget/src/__tests__/fixtures/hir/interdependent.expect.md
index 65c73a2754..9edcd21830 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/interdependent.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/interdependent.expect.md
@@ -28,21 +28,21 @@ function Foo() {}
 
 ```
 bb0:
-  Const mutate a$2 = Call mutate compute$3(read props$1.a)
-  Const mutate b$4 = Call mutate compute$3(read props$1.b)
-  Call mutate foo$5(mutate a$2, mutate b$4)
-  Const mutate $7 = JSX <read Foo$6 a={freeze a$2} b={freeze b$4} ></read Foo$6>
-  Return read $7
+  Const mutate a$9 = Call mutate compute$3(read props$8.a)
+  Const mutate b$10 = Call mutate compute$3(read props$8.b)
+  Call mutate foo$5(mutate a$9, mutate b$10)
+  Const mutate $11 = JSX <read Foo$6 a={freeze a$9} b={freeze b$10} ></read Foo$6>
+  Return read $11
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = compute$3(props$1.a);
-  const b$4 = compute$3(props$1.b);
-  foo$5(a$2, b$4);
-  return <Foo$6 a={a$2} b={b$4}></Foo$6>;
+function Component$0(props$8) {
+  const a$9 = compute$3(props$8.a);
+  const b$10 = compute$3(props$8.b);
+  foo$5(a$9, b$10);
+  return <Foo$6 a={a$9} b={b$10}></Foo$6>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/mutable-lifetime-loops.expect.md b/compiler/forget/src/__tests__/fixtures/hir/mutable-lifetime-loops.expect.md
index 0c1d50d9ef..e75fc071f1 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/mutable-lifetime-loops.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/mutable-lifetime-loops.expect.md
@@ -49,7 +49,7 @@ bb0:
 ## Code
 
 ```javascript
-function mutate$0(x$1, y$2) {
+function mutate$0(x$3, y$4) {
   return;
 }
 
@@ -64,7 +64,7 @@ bb0:
 ## Code
 
 ```javascript
-function cond$0(x$1) {
+function cond$0(x$2) {
   return;
 }
 
@@ -73,52 +73,63 @@ function cond$0(x$1) {
 
 ```
 bb0:
-  Let mutate a$2 = Object {  }
-  Let mutate b$3 = Object {  }
-  Let mutate c$4 = Object {  }
-  Let mutate d$5 = Object {  }
+  Let mutate a$13 = Object {  }
+  Let mutate b$14 = Object {  }
+  Let mutate c$15 = Object {  }
+  Let mutate d$16 = Object {  }
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb3
-  Const mutate $10 = true
-  If (read $10) then:bb3 else:bb2
+  a$18: phi(bb0: a$13, bb3: a$21)
+  b$20: phi(bb0: b$14, bb3: b$23)
+  c$22: phi(bb0: c$15, bb3: c$25)
+  d$24: phi(bb0: d$16, bb3: d$26)
+  mutate$27: phi(bb0: mutate$7, bb3: mutate$27)
+  cond$28: phi(bb0: cond$8, bb3: cond$28)
+  Const mutate $17 = true
+  If (read $17) then:bb3 else:bb2
 bb3:
   predecessor blocks: bb1
-  Let mutate z$6 = read a$2
-  Reassign mutate a$2 = read b$3
-  Reassign mutate b$3 = read c$4
-  Reassign mutate c$4 = read d$5
-  Reassign mutate d$5 = read z$6
-  Call mutate mutate$7(mutate a$2, mutate b$3)
-  Const mutate $9 = Call mutate cond$8(mutate a$2)
-  If (read $9) then:bb2 else:bb1
+  Let mutate z$19 = read a$18
+  Reassign mutate a$21 = read b$20
+  Reassign mutate b$23 = read c$22
+  Reassign mutate c$25 = read d$24
+  Reassign mutate d$26 = read z$19
+  Call mutate mutate$27(mutate a$21, mutate b$23)
+  Const mutate $29 = Call mutate cond$28(mutate a$21)
+  If (read $29) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb1 bb3
-  If (read a$2) then:bb7 else:bb7
+  a$30: phi(bb1: a$18, bb3: a$21)
+  b$31: phi(bb1: b$20, bb3: b$23)
+  c$32: phi(bb1: c$22, bb3: c$25)
+  d$33: phi(bb1: d$24, bb3: d$26)
+  mutate$35: phi(bb1: mutate$27, bb3: mutate$27)
+  If (read a$30) then:bb7 else:bb7
 bb7:
   predecessor blocks: bb2
-  If (read b$3) then:bb9 else:bb9
+  If (read b$31) then:bb9 else:bb9
 bb9:
   predecessor blocks: bb7
-  If (read c$4) then:bb11 else:bb11
+  If (read c$32) then:bb11 else:bb11
 bb11:
   predecessor blocks: bb9
-  If (read d$5) then:bb13 else:bb13
+  If (read d$33) then:bb13 else:bb13
 bb13:
   predecessor blocks: bb11
-  Const mutate $11 = null
-  Call mutate mutate$7(mutate d$5, read $11)
+  Const mutate $34 = null
+  Call mutate mutate$35(mutate d$33, read $34)
   Return
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  let a$2 = {};
-  let b$3 = {};
-  let c$4 = {};
-  let d$5 = {};
+function Component$0(props$12) {
+  let a$13 = {};
+  let b$14 = {};
+  let c$15 = {};
+  let d$16 = {};
   ("<<TODO: handle complex control flow in codegen>>");
 }
 
diff --git a/compiler/forget/src/__tests__/fixtures/hir/mutable-lifetime-with-aliasing.expect.md b/compiler/forget/src/__tests__/fixtures/hir/mutable-lifetime-with-aliasing.expect.md
index 01798e5527..b9ffe4ca10 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/mutable-lifetime-with-aliasing.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/mutable-lifetime-with-aliasing.expect.md
@@ -45,7 +45,7 @@ bb0:
 ## Code
 
 ```javascript
-function mutate$0(x$1, y$2) {
+function mutate$0(x$3, y$4) {
   return;
 }
 
@@ -54,202 +54,202 @@ function mutate$0(x$1, y$2) {
 
 ```
 bb0:
-  Const mutate a$2 = Object {  }
-  Const mutate b$3 = Array [read a$2]
-  Const mutate c$4 = Object {  }
-  Const mutate d$5 = Object { c: read c$4 }
-  Const mutate x$6 = Object {  }
-  Reassign mutate x$6.b = read b$3
-  Const mutate y$7 = Call mutate mutate$8(mutate x$6, mutate d$5)
-  If (read a$2) then:bb1 else:bb1
+  Const mutate a$11 = Object {  }
+  Const mutate b$12 = Array [read a$11]
+  Const mutate c$13 = Object {  }
+  Const mutate d$14 = Object { c: read c$13 }
+  Const mutate x$15 = Object {  }
+  Reassign mutate x$15.b = read b$12
+  Const mutate y$16 = Call mutate mutate$8(mutate x$15, mutate d$14)
+  If (read a$11) then:bb1 else:bb1
 bb1:
   predecessor blocks: bb0
-  If (read b$3) then:bb3 else:bb3
+  If (read b$12) then:bb3 else:bb3
 bb3:
   predecessor blocks: bb1
-  If (read c$4) then:bb5 else:bb5
+  If (read c$13) then:bb5 else:bb5
 bb5:
   predecessor blocks: bb3
-  If (read d$5) then:bb7 else:bb7
+  If (read d$14) then:bb7 else:bb7
 bb7:
   predecessor blocks: bb5
-  If (read y$7) then:bb9 else:bb9
+  If (read y$16) then:bb9 else:bb9
 bb9:
   predecessor blocks: bb7
-  Const mutate $9 = null
-  Call mutate mutate$8(mutate x$6, read $9)
+  Const mutate $17 = null
+  Call mutate mutate$8(mutate x$15, read $17)
   Return
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const a$2 = {};
-  const b$3 = [a$2];
-  const c$4 = {};
-  const d$5 = {
-    c: c$4,
+function Component$0(props$10) {
+  const a$11 = {};
+  const b$12 = [a$11];
+  const c$13 = {};
+  const d$14 = {
+    c: c$13,
   };
-  const x$6 = {};
-  x$6 = b$3;
-  const y$7 = mutate$8(x$6, d$5);
-  if (a$2) {
-    if (b$3) {
-      if (c$4) {
-        if (d$5) {
-          if (y$7) {
-            mutate$8(x$6, null);
+  const x$15 = {};
+  x$15 = b$12;
+  const y$16 = mutate$8(x$15, d$14);
+  if (a$11) {
+    if (b$12) {
+      if (c$13) {
+        if (d$14) {
+          if (y$16) {
+            mutate$8(x$15, null);
             return;
           }
 
-          mutate$8(x$6, null);
+          mutate$8(x$15, null);
           return;
         }
 
-        if (y$7) {
-          mutate$8(x$6, null);
+        if (y$16) {
+          mutate$8(x$15, null);
           return;
         }
 
-        mutate$8(x$6, null);
+        mutate$8(x$15, null);
         return;
       }
 
-      if (d$5) {
-        if (y$7) {
-          mutate$8(x$6, null);
+      if (d$14) {
+        if (y$16) {
+          mutate$8(x$15, null);
           return;
         }
 
-        mutate$8(x$6, null);
+        mutate$8(x$15, null);
         return;
       }
 
-      if (y$7) {
-        mutate$8(x$6, null);
+      if (y$16) {
+        mutate$8(x$15, null);
         return;
       }
 
-      mutate$8(x$6, null);
+      mutate$8(x$15, null);
       return;
     }
 
-    if (c$4) {
-      if (d$5) {
-        if (y$7) {
-          mutate$8(x$6, null);
+    if (c$13) {
+      if (d$14) {
+        if (y$16) {
+          mutate$8(x$15, null);
           return;
         }
 
-        mutate$8(x$6, null);
+        mutate$8(x$15, null);
         return;
       }
 
-      if (y$7) {
-        mutate$8(x$6, null);
+      if (y$16) {
+        mutate$8(x$15, null);
         return;
       }
 
-      mutate$8(x$6, null);
+      mutate$8(x$15, null);
       return;
     }
 
-    if (d$5) {
-      if (y$7) {
-        mutate$8(x$6, null);
+    if (d$14) {
+      if (y$16) {
+        mutate$8(x$15, null);
         return;
       }
 
-      mutate$8(x$6, null);
+      mutate$8(x$15, null);
       return;
     }
 
-    if (y$7) {
-      mutate$8(x$6, null);
+    if (y$16) {
+      mutate$8(x$15, null);
       return;
     }
 
-    mutate$8(x$6, null);
+    mutate$8(x$15, null);
     return;
   }
 
-  if (b$3) {
-    if (c$4) {
-      if (d$5) {
-        if (y$7) {
-          mutate$8(x$6, null);
+  if (b$12) {
+    if (c$13) {
+      if (d$14) {
+        if (y$16) {
+          mutate$8(x$15, null);
           return;
         }
 
-        mutate$8(x$6, null);
+        mutate$8(x$15, null);
         return;
       }
 
-      if (y$7) {
-        mutate$8(x$6, null);
+      if (y$16) {
+        mutate$8(x$15, null);
         return;
       }
 
-      mutate$8(x$6, null);
+      mutate$8(x$15, null);
       return;
     }
 
-    if (d$5) {
-      if (y$7) {
-        mutate$8(x$6, null);
+    if (d$14) {
+      if (y$16) {
+        mutate$8(x$15, null);
         return;
       }
 
-      mutate$8(x$6, null);
+      mutate$8(x$15, null);
       return;
     }
 
-    if (y$7) {
-      mutate$8(x$6, null);
+    if (y$16) {
+      mutate$8(x$15, null);
       return;
     }
 
-    mutate$8(x$6, null);
+    mutate$8(x$15, null);
     return;
   }
 
-  if (c$4) {
-    if (d$5) {
-      if (y$7) {
-        mutate$8(x$6, null);
+  if (c$13) {
+    if (d$14) {
+      if (y$16) {
+        mutate$8(x$15, null);
         return;
       }
 
-      mutate$8(x$6, null);
+      mutate$8(x$15, null);
       return;
     }
 
-    if (y$7) {
-      mutate$8(x$6, null);
+    if (y$16) {
+      mutate$8(x$15, null);
       return;
     }
 
-    mutate$8(x$6, null);
+    mutate$8(x$15, null);
     return;
   }
 
-  if (d$5) {
-    if (y$7) {
-      mutate$8(x$6, null);
+  if (d$14) {
+    if (y$16) {
+      mutate$8(x$15, null);
       return;
     }
 
-    mutate$8(x$6, null);
+    mutate$8(x$15, null);
     return;
   }
 
-  if (y$7) {
-    mutate$8(x$6, null);
+  if (y$16) {
+    mutate$8(x$15, null);
     return;
   }
 
-  mutate$8(x$6, null);
+  mutate$8(x$15, null);
   return;
 }
 
diff --git a/compiler/forget/src/__tests__/fixtures/hir/property-assignment.expect.md b/compiler/forget/src/__tests__/fixtures/hir/property-assignment.expect.md
index 718fe22e37..da9e4b209a 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/property-assignment.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/property-assignment.expect.md
@@ -17,25 +17,25 @@ function Component(props) {
 
 ```
 bb0:
-  Const mutate x$2 = Object {  }
-  Const mutate y$3 = Array []
-  Reassign mutate x$2.y = read y$3
-  Const mutate child$4 = JSX <read Component$0 data={freeze y$3} ></read Component$0>
-  Call mutate x$2.y.push(read props$1.p0)
-  Const mutate $5 = JSX <read Component$0 data={freeze x$2} >{read child$4}</read Component$0>
-  Return read $5
+  Const mutate x$7 = Object {  }
+  Const mutate y$8 = Array []
+  Reassign mutate x$7.y = read y$8
+  Const mutate child$9 = JSX <read Component$0 data={freeze y$8} ></read Component$0>
+  Call mutate x$7.y.push(read props$6.p0)
+  Const mutate $10 = JSX <read Component$0 data={freeze x$7} >{read child$9}</read Component$0>
+  Return read $10
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  const x$2 = {};
-  const y$3 = [];
-  x$2 = y$3;
-  const child$4 = <Component$0 data={y$3}></Component$0>;
-  x$2.y.push(props$1.p0);
-  return <Component$0 data={x$2}>{child$4}</Component$0>;
+function Component$0(props$6) {
+  const x$7 = {};
+  const y$8 = [];
+  x$7 = y$8;
+  const child$9 = <Component$0 data={y$8}></Component$0>;
+  x$7.y.push(props$6.p0);
+  return <Component$0 data={x$7}>{child$9}</Component$0>;
 }
 
 ```
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 4919c5c3a6..e45c81ef9c 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/reassignment-conditional.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/reassignment-conditional.expect.md
@@ -23,38 +23,42 @@ function Component(props) {
 
 ```
 bb0:
-  Let mutate x$2 = Array []
-  Call mutate x$2.push(read props$1.p0)
-  Let mutate y$3 = read x$2
-  If (read props$1.p1) then:bb2 else:bb1
+  Let mutate x$7 = Array []
+  Call mutate x$7.push(read props$6.p0)
+  Let mutate y$8 = read x$7
+  If (read props$6.p1) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Reassign mutate x$2 = Array []
+  Reassign mutate x$9 = Array []
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb2
-  Let mutate _$4 = JSX <read Component$0 x={freeze x$2} ></read Component$0>
-  Call read y$3.push(read props$1.p2)
-  Const mutate $5 = JSX <read Component$0 x={read x$2} y={read y$3} ></read Component$0>
-  Return read $5
+  Component$10: phi(bb0: Component$0, bb2: Component$0)
+  x$11: phi(bb0: x$7, bb2: x$9)
+  y$13: phi(bb0: y$8, bb2: y$8)
+  props$14: phi(bb0: props$6, bb2: props$6)
+  Let mutate _$12 = JSX <read Component$10 x={freeze x$11} ></read Component$10>
+  Call read y$13.push(read props$14.p2)
+  Const mutate $15 = JSX <read Component$10 x={read x$11} y={read y$13} ></read Component$10>
+  Return read $15
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  let x$2 = [];
-  x$2.push(props$1.p0);
-  let y$3 = x$2;
-  if (props$1.p1) {
-    x$2 = [];
+function Component$0(props$6) {
+  let x$7 = [];
+  x$7.push(props$6.p0);
+  let y$8 = x$7;
+  if (props$6.p1) {
+    x$9 = [];
     ("<<TODO: handle complex control flow in codegen>>");
   }
 
-  let _$4 = <Component$0 x={x$2}></Component$0>;
+  let _$12 = <Component$10 x={x$11}></Component$10>;
 
-  y$3.push(props$1.p2);
-  return <Component$0 x={x$2} y={y$3}></Component$0>;
+  y$13.push(props$14.p2);
+  return <Component$10 x={x$11} y={y$13}></Component$10>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/reassignment.expect.md b/compiler/forget/src/__tests__/fixtures/hir/reassignment.expect.md
index 6d59785563..f061ee199f 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/reassignment.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/reassignment.expect.md
@@ -21,28 +21,28 @@ function Component(props) {
 
 ```
 bb0:
-  Let mutate x$2 = Array []
-  Call mutate x$2.push(read props$1.p0)
-  Let mutate y$3 = read x$2
-  Reassign mutate x$2 = Array []
-  Let mutate _$4 = JSX <read Component$0 x={freeze x$2} ></read Component$0>
-  Call mutate y$3.push(read props$1.p1)
-  Const mutate $5 = JSX <read Component$0 x={read x$2} y={freeze y$3} ></read Component$0>
-  Return read $5
+  Let mutate x$7 = Array []
+  Call mutate x$7.push(read props$6.p0)
+  Let mutate y$8 = read x$7
+  Reassign mutate x$9 = Array []
+  Let mutate _$10 = JSX <read Component$0 x={freeze x$9} ></read Component$0>
+  Call mutate y$8.push(read props$6.p1)
+  Const mutate $11 = JSX <read Component$0 x={read x$9} y={freeze y$8} ></read Component$0>
+  Return read $11
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  let x$2 = [];
-  x$2.push(props$1.p0);
-  let y$3 = x$2;
-  x$2 = [];
-  let _$4 = <Component$0 x={x$2}></Component$0>;
+function Component$0(props$6) {
+  let x$7 = [];
+  x$7.push(props$6.p0);
+  let y$8 = x$7;
+  x$9 = [];
+  let _$10 = <Component$0 x={x$9}></Component$0>;
 
-  y$3.push(props$1.p1);
-  return <Component$0 x={x$2} y={y$3}></Component$0>;
+  y$8.push(props$6.p1);
+  return <Component$0 x={x$9} y={y$8}></Component$0>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/reverse-postorder.expect.md b/compiler/forget/src/__tests__/fixtures/hir/reverse-postorder.expect.md
index 19081151a9..93ab89000e 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/reverse-postorder.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/reverse-postorder.expect.md
@@ -36,91 +36,92 @@ function Component(props) {
 
 ```
 bb0:
-  Let mutate x$2 = undefined
-  If (read props$1.cond) then:bb2 else:bb10
+  Let mutate x$7 = undefined
+  If (read props$6.cond) then:bb2 else:bb10
 bb2:
   predecessor blocks: bb0
-  Const mutate $3 = 2
-  Const mutate $4 = 1
-  Const mutate $5 = 0
-  Switch (<unknown> props$1.test)
-    Case read $5: bb8
-    Case read $4: bb6
-    Case read $3: bb4
+  Const mutate $8 = 2
+  Const mutate $9 = 1
+  Const mutate $10 = 0
+  Switch (<unknown> props$6.test)
+    Case read $10: bb8
+    Case read $9: bb6
+    Case read $8: bb4
     Default: bb4
 bb8:
   predecessor blocks: bb2
-  Reassign mutate x$2 = read props$1.v0
+  Reassign mutate x$11 = read props$6.v0
   Goto bb1
 bb6:
   predecessor blocks: bb2
-  Reassign mutate x$2 = read props$1.v1
+  Reassign mutate x$12 = read props$6.v1
   Goto bb1
 bb4:
   predecessor blocks: bb2
-  Reassign mutate x$2 = read props$1.v2
+  Reassign mutate x$13 = read props$6.v2
   Goto bb1
 bb10:
   predecessor blocks: bb0
-  If (read props$1.cond2) then:bb12 else:bb13
+  If (read props$6.cond2) then:bb12 else:bb13
 bb12:
   predecessor blocks: bb10
-  Reassign mutate x$2 = read props$1.b
+  Reassign mutate x$14 = read props$6.b
   Goto bb1
 bb13:
   predecessor blocks: bb10
-  Reassign mutate x$2 = read props$1.c
+  Reassign mutate x$15 = read props$6.c
   Goto bb1
 bb1:
   predecessor blocks: bb13 bb12 bb8 bb6 bb4
-  read x$2
+  x$16: phi(bb13: x$15, bb12: x$14, bb8: x$11, bb6: x$12, bb4: x$13)
+  read x$16
   Return
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  let x$2 = undefined;
-  if (props$1.cond) {
-    switch (props$1.test) {
+function Component$0(props$6) {
+  let x$7 = undefined;
+  if (props$6.cond) {
+    switch (props$6.test) {
       case 0: {
-        x$2 = props$1.v0;
+        x$11 = props$6.v0;
         ("<<TODO: handle complex control flow in codegen>>");
       }
 
       case 1: {
-        x$2 = props$1.v1;
+        x$12 = props$6.v1;
         ("<<TODO: handle complex control flow in codegen>>");
       }
 
       case 2: {
-        x$2 = props$1.v2;
+        x$13 = props$6.v2;
         ("<<TODO: handle complex control flow in codegen>>");
       }
 
       default: {
-        x$2 = props$1.v2;
+        x$13 = props$6.v2;
         ("<<TODO: handle complex control flow in codegen>>");
       }
     }
 
-    x$2;
+    x$16;
     return;
   } else {
-    if (props$1.cond2) {
-      x$2 = props$1.b;
+    if (props$6.cond2) {
+      x$14 = props$6.b;
       ("<<TODO: handle complex control flow in codegen>>");
     } else {
-      x$2 = props$1.c;
+      x$15 = props$6.c;
       ("<<TODO: handle complex control flow in codegen>>");
     }
 
-    x$2;
+    x$16;
     return;
   }
 
-  x$2;
+  x$16;
   return;
 }
 
diff --git a/compiler/forget/src/__tests__/fixtures/hir/simple.expect.md b/compiler/forget/src/__tests__/fixtures/hir/simple.expect.md
index c7f670aafc..950c65842d 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/simple.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/simple.expect.md
@@ -15,28 +15,28 @@ function foo(x, y) {
 
 ```
 bb0:
-  If (read x$1) then:bb2 else:bb1
+  If (read x$8) then:bb2 else:bb1
 bb2:
   predecessor blocks: bb0
-  Const mutate $3 = false
-  Const mutate $4 = Call read foo$0(read $3, read y$2)
-  Return freeze $4
+  Const mutate $10 = false
+  Const mutate $11 = Call read foo$0(read $10, read y$9)
+  Return freeze $11
 bb1:
   predecessor blocks: bb0
-  Const mutate $5 = 10
-  Const mutate $6 = Binary read y$2 * read $5
-  Const mutate $7 = Array [read $6]
-  Return freeze $7
+  Const mutate $12 = 10
+  Const mutate $13 = Binary read y$9 * read $12
+  Const mutate $14 = Array [read $13]
+  Return freeze $14
 ```
 
 ## Code
 
 ```javascript
-function foo$0(x$1, y$2) {
-  if (x$1) {
-    return foo$0(false, y$2);
+function foo$0(x$8, y$9) {
+  if (x$8) {
+    return foo$0(false, y$9);
   }
-  return [y$2 * 10];
+  return [y$9 * 10];
 }
 
 ```
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 299f300081..009297f8a1 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
@@ -32,46 +32,50 @@ function Component(props) {
 
 ```
 bb0:
-  Let mutate x$2 = Array []
-  Let mutate y$3 = undefined
-  Const mutate $4 = false
-  Const mutate $5 = true
-  Const mutate $6 = 1
-  Switch (<unknown> props$1.p0)
-    Case read $6: bb1
-    Case read $5: bb6
+  Let mutate x$10 = Array []
+  Let mutate y$11 = undefined
+  Const mutate $12 = false
+  Const mutate $13 = true
+  Const mutate $14 = 1
+  Switch (<unknown> props$9.p0)
+    Case read $14: bb1
+    Case read $13: bb6
     Default: bb1
-    Case read $4: bb2
+    Case read $12: bb2
 bb6:
   predecessor blocks: bb0
-  Call mutate x$2.push(read props$1.p2)
-  Reassign mutate y$3 = Array []
+  Call mutate x$10.push(read props$9.p2)
+  Reassign mutate y$15 = Array []
   Goto bb1
 bb2:
   predecessor blocks: bb0
-  Reassign mutate y$3 = read x$2
+  Reassign mutate y$16 = read x$10
   Goto bb1
 bb1:
   predecessor blocks: bb0 bb6 bb2
-  Const mutate child$7 = JSX <read Component$0 data={freeze x$2} ></read Component$0>
-  Call read y$3.push(read props$1.p4)
-  Const mutate $8 = JSX <read Component$0 data={freeze y$3} >{read child$7}</read Component$0>
-  Return read $8
+  Component$17: phi(bb0: Component$0, bb6: Component$0, bb2: Component$0)
+  x$18: phi(bb0: x$10, bb6: x$10, bb2: x$10)
+  y$20: phi(bb0: y$11, bb6: y$15, bb2: y$16)
+  props$21: phi(bb0: props$9, bb6: props$9, bb2: props$9)
+  Const mutate child$19 = JSX <read Component$17 data={freeze x$18} ></read Component$17>
+  Call read y$20.push(read props$21.p4)
+  Const mutate $22 = JSX <read Component$17 data={freeze y$20} >{read child$19}</read Component$17>
+  Return read $22
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  let x$2 = [];
-  let y$3 = undefined;
-  switch (props$1.p0) {
+function Component$0(props$9) {
+  let x$10 = [];
+  let y$11 = undefined;
+  switch (props$9.p0) {
     case 1:
       break;
 
     case true: {
-      x$2.push(props$1.p2);
-      y$3 = [];
+      x$10.push(props$9.p2);
+      y$15 = [];
       ("<<TODO: handle complex control flow in codegen>>");
     }
 
@@ -79,14 +83,14 @@ function Component$0(props$1) {
       break;
 
     case false: {
-      y$3 = x$2;
+      y$16 = x$10;
       ("<<TODO: handle complex control flow in codegen>>");
     }
   }
 
-  const child$7 = <Component$0 data={x$2}></Component$0>;
-  y$3.push(props$1.p4);
-  return <Component$0 data={y$3}>{child$7}</Component$0>;
+  const child$19 = <Component$17 data={x$18}></Component$17>;
+  y$20.push(props$21.p4);
+  return <Component$17 data={y$20}>{child$19}</Component$17>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/fixtures/hir/switch.expect.md b/compiler/forget/src/__tests__/fixtures/hir/switch.expect.md
index f026f2b65e..921ed4febf 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/switch.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/switch.expect.md
@@ -28,55 +28,62 @@ function Component(props) {
 
 ```
 bb0:
-  Let mutate x$2 = Array []
-  Let mutate y$3 = undefined
-  Const mutate $4 = false
-  Const mutate $5 = true
-  Switch (<unknown> props$1.p0)
-    Case read $5: bb4
-    Case read $4: bb2
+  Let mutate x$9 = Array []
+  Let mutate y$10 = undefined
+  Const mutate $11 = false
+  Const mutate $12 = true
+  Switch (<unknown> props$8.p0)
+    Case read $12: bb4
+    Case read $11: bb2
     Default: bb1
 bb4:
   predecessor blocks: bb0
-  Call mutate x$2.push(read props$1.p2)
-  Call mutate x$2.push(read props$1.p3)
-  Reassign mutate y$3 = Array []
+  Call mutate x$9.push(read props$8.p2)
+  Call mutate x$9.push(read props$8.p3)
+  Reassign mutate y$13 = Array []
   Goto bb2
 bb2:
   predecessor blocks: bb4 bb0
-  Reassign mutate y$3 = read x$2
+  x$14: phi(bb4: x$9, bb0: x$9)
+  Component$17: phi(bb4: Component$0, bb0: Component$0)
+  props$22: phi(bb4: props$8, bb0: props$8)
+  Reassign mutate y$15 = read x$14
   Goto bb1
 bb1:
   predecessor blocks: bb2 bb0
-  Const mutate child$6 = JSX <read Component$0 data={freeze x$2} ></read Component$0>
-  Call read y$3.push(read props$1.p4)
-  Const mutate $7 = JSX <read Component$0 data={read y$3} >{read child$6}</read Component$0>
-  Return read $7
+  Component$16: phi(bb2: Component$17, bb0: Component$0)
+  x$18: phi(bb2: x$14, bb0: x$9)
+  y$20: phi(bb2: y$15, bb0: y$10)
+  props$21: phi(bb2: props$22, bb0: props$8)
+  Const mutate child$19 = JSX <read Component$16 data={freeze x$18} ></read Component$16>
+  Call read y$20.push(read props$21.p4)
+  Const mutate $23 = JSX <read Component$16 data={read y$20} >{read child$19}</read Component$16>
+  Return read $23
 ```
 
 ## Code
 
 ```javascript
-function Component$0(props$1) {
-  let x$2 = [];
-  let y$3 = undefined;
-  switch (props$1.p0) {
+function Component$0(props$8) {
+  let x$9 = [];
+  let y$10 = undefined;
+  switch (props$8.p0) {
     case true: {
-      x$2.push(props$1.p2);
-      x$2.push(props$1.p3);
-      y$3 = [];
+      x$9.push(props$8.p2);
+      x$9.push(props$8.p3);
+      y$13 = [];
       ("<<TODO: handle complex control flow in codegen>>");
     }
 
     case false: {
-      y$3 = x$2;
+      y$15 = x$14;
       ("<<TODO: handle complex control flow in codegen>>");
     }
   }
 
-  const child$6 = <Component$0 data={x$2}></Component$0>;
-  y$3.push(props$1.p4);
-  return <Component$0 data={y$3}>{child$6}</Component$0>;
+  const child$19 = <Component$16 data={x$18}></Component$16>;
+  y$20.push(props$21.p4);
+  return <Component$16 data={y$20}>{child$19}</Component$16>;
 }
 
 ```
diff --git a/compiler/forget/src/__tests__/hir-test.ts b/compiler/forget/src/__tests__/hir-test.ts
index 0bc636ce16..08c8e27963 100644
--- a/compiler/forget/src/__tests__/hir-test.ts
+++ b/compiler/forget/src/__tests__/hir-test.ts
@@ -47,9 +47,7 @@ describe("React Forget (HIR version)", () => {
           enter(nodePath) {
             const env: Environment = new Environment();
             const ir: HIRFunction = lower(nodePath, env);
-            if (file.startsWith("ssa")) {
-              buildSSA(ir, env);
-            }
+            buildSSA(ir, env);
             inferReferenceEffects(ir);
             // const lifetimeGraph = buildDefUseGraph(ir);
             const textHIR = printHIR(ir.body);