diff --git a/src/passes/CodeFolding.cpp b/src/passes/CodeFolding.cpp
index 21527da6b18..47e7916fab0 100644
--- a/src/passes/CodeFolding.cpp
+++ b/src/passes/CodeFolding.cpp
@@ -243,6 +243,10 @@ struct CodeFolding : public WalkerPass<ControlFlowWalker<CodeFolding>> {
     if (!curr->ifFalse) {
       return;
     }
+    if (curr->ifTrue->type.isConcrete()) {
+      // We don't support folding tails that produce values.
+      return;
+    }
     // if both sides are identical, this is easy to fold
     if (ExpressionAnalyzer::equal(curr->ifTrue, curr->ifFalse)) {
       Builder builder(*getModule());
diff --git a/test/lit/passes/code-folding_enable-threads.wast b/test/lit/passes/code-folding_enable-threads.wast
index b07000278ed..3df2d8c8aeb 100644
--- a/test/lit/passes/code-folding_enable-threads.wast
+++ b/test/lit/passes/code-folding_enable-threads.wast
@@ -83,11 +83,18 @@
   )
  )
  ;; CHECK:      (func $negative-zero-b (result f32)
- ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:  (if (result f32)
  ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block $label$0 (result f32)
- ;; CHECK-NEXT:   (f32.const -0)
+ ;; CHECK-NEXT:   (then
+ ;; CHECK-NEXT:    (block $label$0 (result f32)
+ ;; CHECK-NEXT:     (f32.const -0)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (else
+ ;; CHECK-NEXT:    (block $label$1 (result f32)
+ ;; CHECK-NEXT:     (f32.const -0)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $negative-zero-b (result f32)
@@ -106,11 +113,18 @@
   )
  )
  ;; CHECK:      (func $negative-zero-c (result f32)
- ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:  (if (result f32)
  ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block $label$0 (result f32)
- ;; CHECK-NEXT:   (f32.const 0)
+ ;; CHECK-NEXT:   (then
+ ;; CHECK-NEXT:    (block $label$0 (result f32)
+ ;; CHECK-NEXT:     (f32.const 0)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (else
+ ;; CHECK-NEXT:    (block $label$1 (result f32)
+ ;; CHECK-NEXT:     (f32.const 0)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $negative-zero-c (result f32)
@@ -482,3 +496,36 @@
   )
  )
 )
+
+(module
+ ;; CHECK:      (type $0 (func))
+
+ ;; CHECK:      (func $unreachable-if-concrete-arms
+ ;; CHECK-NEXT:  (drop
+ ;; CHECK-NEXT:   (if (result i32)
+ ;; CHECK-NEXT:    (unreachable)
+ ;; CHECK-NEXT:    (then
+ ;; CHECK-NEXT:     (i32.const 1)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:    (else
+ ;; CHECK-NEXT:     (nop)
+ ;; CHECK-NEXT:     (i32.const 1)
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT:  (unreachable)
+ ;; CHECK-NEXT: )
+ (func $unreachable-if-concrete-arms
+  (if (result i32)
+   (unreachable)
+   (then
+    (i32.const 1)
+   )
+   (else
+    (nop)
+    (i32.const 1)
+   )
+  )
+  (unreachable)
+ )
+)
diff --git a/test/lit/passes/inlining-optimizing_optimize-level=3.wast b/test/lit/passes/inlining-optimizing_optimize-level=3.wast
index f6df7305620..9e514cc2733 100644
--- a/test/lit/passes/inlining-optimizing_optimize-level=3.wast
+++ b/test/lit/passes/inlining-optimizing_optimize-level=3.wast
@@ -5742,43 +5742,44 @@
  ;; CHECK-NEXT:                                   )
  ;; CHECK-NEXT:                                  )
  ;; CHECK-NEXT:                                 )
- ;; CHECK-NEXT:                                 (if
- ;; CHECK-NEXT:                                  (i32.and
- ;; CHECK-NEXT:                                   (local.get $9)
- ;; CHECK-NEXT:                                   (i32.const 8)
- ;; CHECK-NEXT:                                  )
- ;; CHECK-NEXT:                                  (then
- ;; CHECK-NEXT:                                   (local.set $7
+ ;; CHECK-NEXT:                                 (local.set $5
+ ;; CHECK-NEXT:                                  (if (result i32)
+ ;; CHECK-NEXT:                                   (i32.and
  ;; CHECK-NEXT:                                    (local.get $9)
+ ;; CHECK-NEXT:                                    (i32.const 8)
  ;; CHECK-NEXT:                                   )
- ;; CHECK-NEXT:                                   (local.set $6
- ;; CHECK-NEXT:                                    (select
- ;; CHECK-NEXT:                                     (local.tee $5
- ;; CHECK-NEXT:                                      (i32.add
- ;; CHECK-NEXT:                                       (i32.sub
- ;; CHECK-NEXT:                                        (local.get $23)
- ;; CHECK-NEXT:                                        (local.get $8)
+ ;; CHECK-NEXT:                                   (then
+ ;; CHECK-NEXT:                                    (local.set $7
+ ;; CHECK-NEXT:                                     (local.get $9)
+ ;; CHECK-NEXT:                                    )
+ ;; CHECK-NEXT:                                    (local.set $6
+ ;; CHECK-NEXT:                                     (select
+ ;; CHECK-NEXT:                                      (local.tee $5
+ ;; CHECK-NEXT:                                       (i32.add
+ ;; CHECK-NEXT:                                        (i32.sub
+ ;; CHECK-NEXT:                                         (local.get $23)
+ ;; CHECK-NEXT:                                         (local.get $8)
+ ;; CHECK-NEXT:                                        )
+ ;; CHECK-NEXT:                                        (i32.const 1)
  ;; CHECK-NEXT:                                       )
- ;; CHECK-NEXT:                                       (i32.const 1)
  ;; CHECK-NEXT:                                      )
- ;; CHECK-NEXT:                                     )
- ;; CHECK-NEXT:                                     (local.get $6)
- ;; CHECK-NEXT:                                     (i32.gt_s
- ;; CHECK-NEXT:                                      (local.get $5)
  ;; CHECK-NEXT:                                      (local.get $6)
+ ;; CHECK-NEXT:                                      (i32.gt_s
+ ;; CHECK-NEXT:                                       (local.get $5)
+ ;; CHECK-NEXT:                                       (local.get $6)
+ ;; CHECK-NEXT:                                      )
  ;; CHECK-NEXT:                                     )
  ;; CHECK-NEXT:                                    )
+ ;; CHECK-NEXT:                                    (local.get $8)
  ;; CHECK-NEXT:                                   )
- ;; CHECK-NEXT:                                  )
- ;; CHECK-NEXT:                                  (else
- ;; CHECK-NEXT:                                   (local.set $7
- ;; CHECK-NEXT:                                    (local.get $9)
+ ;; CHECK-NEXT:                                   (else
+ ;; CHECK-NEXT:                                    (local.set $7
+ ;; CHECK-NEXT:                                     (local.get $9)
+ ;; CHECK-NEXT:                                    )
+ ;; CHECK-NEXT:                                    (local.get $8)
  ;; CHECK-NEXT:                                   )
  ;; CHECK-NEXT:                                  )
  ;; CHECK-NEXT:                                 )
- ;; CHECK-NEXT:                                 (local.set $5
- ;; CHECK-NEXT:                                  (local.get $8)
- ;; CHECK-NEXT:                                 )
  ;; CHECK-NEXT:                                 (local.set $8
  ;; CHECK-NEXT:                                  (i32.const 0)
  ;; CHECK-NEXT:                                 )
diff --git a/test/passes/remove-unused-names_code-folding.txt b/test/passes/remove-unused-names_code-folding.txt
index d0486b3c784..4b228bd4ee1 100644
--- a/test/passes/remove-unused-names_code-folding.txt
+++ b/test/passes/remove-unused-names_code-folding.txt
@@ -26,13 +26,19 @@
    )
   )
   (drop
-   (block (result i32)
-    (drop
-     (i32.const 0)
+   (if (result i32)
+    (i32.const 0)
+    (then
+     (i32.add
+      (i32.const 1)
+      (i32.const 2)
+     )
     )
-    (i32.add
-     (i32.const 1)
-     (i32.const 2)
+    (else
+     (i32.add
+      (i32.const 1)
+      (i32.const 2)
+     )
     )
    )
   )
@@ -218,54 +224,61 @@
    (unreachable)
   )
   (drop
-   (block (result i32)
-    (if
-     (i32.const 2)
-     (then
-      (drop
-       (i32.const -1234)
-      )
-      (drop
-       (i32.const -1000)
-      )
+   (if (result i32)
+    (i32.const 2)
+    (then
+     (drop
+      (i32.const -1234)
      )
-     (else
-      (drop
-       (i32.const 999)
-      )
+     (drop
+      (i32.const -1000)
      )
+     (drop
+      (i32.const 1)
+     )
+     (nop)
+     (unreachable)
+     (i32.const 2)
     )
-    (drop
-     (i32.const 1)
+    (else
+     (drop
+      (i32.const 999)
+     )
+     (drop
+      (i32.const 1)
+     )
+     (nop)
+     (unreachable)
+     (i32.const 2)
     )
-    (nop)
-    (unreachable)
-    (i32.const 2)
    )
   )
   (drop
-   (block (result i32)
-    (if
-     (i32.const 3)
-     (then
-      (drop
-       (i32.const -1234)
-      )
-      (drop
-       (i32.const -1000)
-      )
+   (if (result i32)
+    (i32.const 3)
+    (then
+     (drop
+      (i32.const -1234)
      )
-     (else
-      (drop
-       (i32.const 999)
-      )
+     (drop
+      (i32.const -1000)
      )
+     (drop
+      (i32.const 1)
+     )
+     (nop)
+     (i32.const 2)
     )
-    (drop
-     (i32.const 1)
+    (else
+     (drop
+      (i32.const 999)
+     )
+     (drop
+      (i32.const 1)
+     )
+     (nop)
+     (i32.const 2)
     )
-    (nop)
-    (i32.const 2)
    )
   )
  )
@@ -388,28 +401,28 @@
     )
     (drop
      (block (result i32)
-      (block (result i32)
-       (if
-        (i32.const 9999)
-        (then
-         (drop
-          (i32.const -51234)
-         )
-         (drop
-          (i32.const -51000)
-         )
+      (if (result i32)
+       (i32.const 9999)
+       (then
+        (drop
+         (i32.const -51234)
         )
-        (else
-         (drop
-          (i32.const 5999)
-         )
-         (drop
-          (i32.const 51)
-         )
+        (drop
+         (i32.const -51000)
         )
+        (unreachable)
+        (i32.const 10)
+       )
+       (else
+        (drop
+         (i32.const 5999)
+        )
+        (drop
+         (i32.const 51)
+        )
+        (unreachable)
+        (i32.const 10)
        )
-       (unreachable)
-       (i32.const 10)
       )
      )
     )
@@ -1523,11 +1536,15 @@
   )
   (nop)
   (drop
-   (block (result i32)
-    (drop
-     (unreachable)
+   (if (result i32)
+    (unreachable)
+    (then
+     (i32.add
+      (i32.const 1)
+      (i32.const 2)
+     )
     )
-    (block (result i32)
+    (else
      (i32.add
       (i32.const 1)
       (i32.const 2)
@@ -1874,20 +1891,19 @@
     (i32.const 1)
    )
   )
-  (block (result i32)
-   (if
-    (local.get $x)
-    (then
-    )
-    (else
-     (drop
-      (call $if-suffix
-       (i32.const -2)
-      )
+  (if (result i32)
+   (local.get $x)
+   (then
+    (i32.const 2)
+   )
+   (else
+    (drop
+     (call $if-suffix
+      (i32.const -2)
      )
     )
+    (i32.const 2)
    )
-   (i32.const 2)
   )
  )
 )