Merge pull request #811 from WebAssembly/iffify

Some minor if/br_if opts

10 files changed, 559 insertions, 351 deletions

diff --git a/test/emcc_O2_hello_world.fromasm b/test/emcc_O2_hello_world.fromasm
index 632906543..e4cbfdce5 100644
--- a/test/emcc_O2_hello_world.fromasm
+++ b/test/emcc_O2_hello_world.fromasm
@@ -8987,48 +8987,46 @@
       )
       (block
         (loop $while-in
-          (block $while-out
-            (br_if $while-out
-              (i32.eqz
-                (i32.and
-                  (get_local $0)
-                  (i32.const 3)
-                )
-              )
-            )
-            (if
-              (i32.eqz
-                (get_local $2)
-              )
-              (return
-                (get_local $3)
-              )
-            )
-            (i32.store8
+          (if
+            (i32.and
               (get_local $0)
-              (i32.load8_s
-                (get_local $1)
-              )
+              (i32.const 3)
             )
-            (set_local $0
-              (i32.add
+            (block
+              (if
+                (i32.eqz
+                  (get_local $2)
+                )
+                (return
+                  (get_local $3)
+                )
+              )
+              (i32.store8
                 (get_local $0)
-                (i32.const 1)
+                (i32.load8_s
+                  (get_local $1)
+                )
               )
-            )
-            (set_local $1
-              (i32.add
-                (get_local $1)
-                (i32.const 1)
+              (set_local $0
+                (i32.add
+                  (get_local $0)
+                  (i32.const 1)
+                )
               )
-            )
-            (set_local $2
-              (i32.sub
-                (get_local $2)
-                (i32.const 1)
+              (set_local $1
+                (i32.add
+                  (get_local $1)
+                  (i32.const 1)
+                )
               )
+              (set_local $2
+                (i32.sub
+                  (get_local $2)
+                  (i32.const 1)
+                )
+              )
+              (br $while-in)
             )
-            (br $while-in)
           )
         )
         (loop $while-in1
diff --git a/test/emcc_O2_hello_world.fromasm.imprecise b/test/emcc_O2_hello_world.fromasm.imprecise
index 36a8a7099..684fa5a6b 100644
--- a/test/emcc_O2_hello_world.fromasm.imprecise
+++ b/test/emcc_O2_hello_world.fromasm.imprecise
@@ -8985,48 +8985,46 @@
       )
       (block
         (loop $while-in
-          (block $while-out
-            (br_if $while-out
-              (i32.eqz
-                (i32.and
-                  (get_local $0)
-                  (i32.const 3)
-                )
-              )
-            )
-            (if
-              (i32.eqz
-                (get_local $2)
-              )
-              (return
-                (get_local $3)
-              )
-            )
-            (i32.store8
+          (if
+            (i32.and
               (get_local $0)
-              (i32.load8_s
-                (get_local $1)
-              )
+              (i32.const 3)
             )
-            (set_local $0
-              (i32.add
+            (block
+              (if
+                (i32.eqz
+                  (get_local $2)
+                )
+                (return
+                  (get_local $3)
+                )
+              )
+              (i32.store8
                 (get_local $0)
-                (i32.const 1)
+                (i32.load8_s
+                  (get_local $1)
+                )
               )
-            )
-            (set_local $1
-              (i32.add
-                (get_local $1)
-                (i32.const 1)
+              (set_local $0
+                (i32.add
+                  (get_local $0)
+                  (i32.const 1)
+                )
               )
-            )
-            (set_local $2
-              (i32.sub
-                (get_local $2)
-                (i32.const 1)
+              (set_local $1
+                (i32.add
+                  (get_local $1)
+                  (i32.const 1)
+                )
               )
+              (set_local $2
+                (i32.sub
+                  (get_local $2)
+                  (i32.const 1)
+                )
+              )
+              (br $while-in)
             )
-            (br $while-in)
           )
         )
         (loop $while-in1
diff --git a/test/emcc_hello_world.fromasm b/test/emcc_hello_world.fromasm
index 7443cdaff..904d73289 100644
--- a/test/emcc_hello_world.fromasm
+++ b/test/emcc_hello_world.fromasm
@@ -2050,8 +2050,8 @@
                 )
               )
               (loop $while-in3
-                (block $while-out2
-                  (br_if $while-out2
+                (if
+                  (i32.eqz
                     (i32.and
                       (i32.xor
                         (i32.and
@@ -2073,24 +2073,27 @@
                       )
                     )
                   )
-                  (set_local $2
-                    (i32.add
-                      (get_local $2)
-                      (i32.const 4)
+                  (block
+                    (nop)
+                    (set_local $2
+                      (i32.add
+                        (get_local $2)
+                        (i32.const 4)
+                      )
                     )
-                  )
-                  (br_if $while-in3
-                    (i32.gt_u
-                      (tee_local $0
-                        (i32.add
-                          (get_local $0)
-                          (i32.const -4)
+                    (br_if $while-in3
+                      (i32.gt_u
+                        (tee_local $0
+                          (i32.add
+                            (get_local $0)
+                            (i32.const -4)
+                          )
                         )
+                        (i32.const 3)
                       )
-                      (i32.const 3)
                     )
+                    (br $jumpthreading$inner$0)
                   )
-                  (br $jumpthreading$inner$0)
                 )
               )
               (br $jumpthreading$outer$0)
@@ -4828,29 +4831,30 @@
                                             )
                                           )
                                           (loop $while-in68
-                                            (block $while-out67
-                                              (br_if $while-out67
-                                                (i32.le_u
-                                                  (get_local $5)
-                                                  (get_local $6)
-                                                )
+                                            (if
+                                              (i32.gt_u
+                                                (get_local $5)
+                                                (get_local $6)
                                               )
-                                              (if
-                                                (i32.eqz
-                                                  (i32.load
-                                                    (tee_local $10
-                                                      (i32.add
-                                                        (get_local $5)
-                                                        (i32.const -4)
+                                              (block
+                                                (nop)
+                                                (if
+                                                  (i32.eqz
+                                                    (i32.load
+                                                      (tee_local $10
+                                                        (i32.add
+                                                          (get_local $5)
+                                                          (i32.const -4)
+                                                        )
                                                       )
                                                     )
                                                   )
-                                                )
-                                                (block
-                                                  (set_local $5
-                                                    (get_local $10)
+                                                  (block
+                                                    (set_local $5
+                                                      (get_local $10)
+                                                    )
+                                                    (br $while-in68)
                                                   )
-                                                  (br $while-in68)
                                                 )
                                               )
                                             )
@@ -7234,49 +7238,48 @@
               (i32.const 1)
             )
             (loop $while-in130
-              (block $while-out129
-                (br_if $while-out129
-                  (i32.eqz
-                    (tee_local $1
-                      (i32.load
-                        (i32.add
-                          (get_local $4)
-                          (i32.shl
-                            (get_local $0)
-                            (i32.const 2)
-                          )
-                        )
+              (if
+                (tee_local $1
+                  (i32.load
+                    (i32.add
+                      (get_local $4)
+                      (i32.shl
+                        (get_local $0)
+                        (i32.const 2)
                       )
                     )
                   )
                 )
-                (call $_pop_arg_336
-                  (i32.add
-                    (get_local $3)
-                    (i32.shl
-                      (get_local $0)
-                      (i32.const 3)
+                (block
+                  (nop)
+                  (call $_pop_arg_336
+                    (i32.add
+                      (get_local $3)
+                      (i32.shl
+                        (get_local $0)
+                        (i32.const 3)
+                      )
                     )
+                    (get_local $1)
+                    (get_local $2)
                   )
-                  (get_local $1)
-                  (get_local $2)
-                )
-                (br_if $while-in130
-                  (i32.lt_s
-                    (tee_local $0
-                      (i32.add
-                        (get_local $0)
-                        (i32.const 1)
+                  (br_if $while-in130
+                    (i32.lt_s
+                      (tee_local $0
+                        (i32.add
+                          (get_local $0)
+                          (i32.const 1)
+                        )
                       )
+                      (i32.const 10)
                     )
-                    (i32.const 10)
                   )
-                )
-                (block
-                  (set_local $16
-                    (i32.const 1)
+                  (block
+                    (set_local $16
+                      (i32.const 1)
+                    )
+                    (br $label$break$L343)
                   )
-                  (br $label$break$L343)
                 )
               )
             )
@@ -15700,48 +15703,46 @@
       )
       (block
         (loop $while-in
-          (block $while-out
-            (br_if $while-out
-              (i32.eqz
-                (i32.and
-                  (get_local $0)
-                  (i32.const 3)
-                )
-              )
-            )
-            (if
-              (i32.eqz
-                (get_local $2)
-              )
-              (return
-                (get_local $3)
-              )
-            )
-            (i32.store8
+          (if
+            (i32.and
               (get_local $0)
-              (i32.load8_s
-                (get_local $1)
-              )
+              (i32.const 3)
             )
-            (set_local $0
-              (i32.add
+            (block
+              (if
+                (i32.eqz
+                  (get_local $2)
+                )
+                (return
+                  (get_local $3)
+                )
+              )
+              (i32.store8
                 (get_local $0)
-                (i32.const 1)
+                (i32.load8_s
+                  (get_local $1)
+                )
               )
-            )
-            (set_local $1
-              (i32.add
-                (get_local $1)
-                (i32.const 1)
+              (set_local $0
+                (i32.add
+                  (get_local $0)
+                  (i32.const 1)
+                )
               )
-            )
-            (set_local $2
-              (i32.sub
-                (get_local $2)
-                (i32.const 1)
+              (set_local $1
+                (i32.add
+                  (get_local $1)
+                  (i32.const 1)
+                )
+              )
+              (set_local $2
+                (i32.sub
+                  (get_local $2)
+                  (i32.const 1)
+                )
               )
+              (br $while-in)
             )
-            (br $while-in)
           )
         )
         (loop $while-in1
diff --git a/test/emcc_hello_world.fromasm.imprecise b/test/emcc_hello_world.fromasm.imprecise
index b3ce6e84e..c8df16aa6 100644
--- a/test/emcc_hello_world.fromasm.imprecise
+++ b/test/emcc_hello_world.fromasm.imprecise
@@ -2043,8 +2043,8 @@
                 )
               )
               (loop $while-in3
-                (block $while-out2
-                  (br_if $while-out2
+                (if
+                  (i32.eqz
                     (i32.and
                       (i32.xor
                         (i32.and
@@ -2066,24 +2066,27 @@
                       )
                     )
                   )
-                  (set_local $2
-                    (i32.add
-                      (get_local $2)
-                      (i32.const 4)
+                  (block
+                    (nop)
+                    (set_local $2
+                      (i32.add
+                        (get_local $2)
+                        (i32.const 4)
+                      )
                     )
-                  )
-                  (br_if $while-in3
-                    (i32.gt_u
-                      (tee_local $0
-                        (i32.add
-                          (get_local $0)
-                          (i32.const -4)
+                    (br_if $while-in3
+                      (i32.gt_u
+                        (tee_local $0
+                          (i32.add
+                            (get_local $0)
+                            (i32.const -4)
+                          )
                         )
+                        (i32.const 3)
                       )
-                      (i32.const 3)
                     )
+                    (br $jumpthreading$inner$0)
                   )
-                  (br $jumpthreading$inner$0)
                 )
               )
               (br $jumpthreading$outer$0)
@@ -4820,29 +4823,30 @@
                                             )
                                           )
                                           (loop $while-in68
-                                            (block $while-out67
-                                              (br_if $while-out67
-                                                (i32.le_u
-                                                  (get_local $5)
-                                                  (get_local $6)
-                                                )
+                                            (if
+                                              (i32.gt_u
+                                                (get_local $5)
+                                                (get_local $6)
                                               )
-                                              (if
-                                                (i32.eqz
-                                                  (i32.load
-                                                    (tee_local $10
-                                                      (i32.add
-                                                        (get_local $5)
-                                                        (i32.const -4)
+                                              (block
+                                                (nop)
+                                                (if
+                                                  (i32.eqz
+                                                    (i32.load
+                                                      (tee_local $10
+                                                        (i32.add
+                                                          (get_local $5)
+                                                          (i32.const -4)
+                                                        )
                                                       )
                                                     )
                                                   )
-                                                )
-                                                (block
-                                                  (set_local $5
-                                                    (get_local $10)
+                                                  (block
+                                                    (set_local $5
+                                                      (get_local $10)
+                                                    )
+                                                    (br $while-in68)
                                                   )
-                                                  (br $while-in68)
                                                 )
                                               )
                                             )
@@ -7220,49 +7224,48 @@
               (i32.const 1)
             )
             (loop $while-in130
-              (block $while-out129
-                (br_if $while-out129
-                  (i32.eqz
-                    (tee_local $1
-                      (i32.load
-                        (i32.add
-                          (get_local $4)
-                          (i32.shl
-                            (get_local $0)
-                            (i32.const 2)
-                          )
-                        )
+              (if
+                (tee_local $1
+                  (i32.load
+                    (i32.add
+                      (get_local $4)
+                      (i32.shl
+                        (get_local $0)
+                        (i32.const 2)
                       )
                     )
                   )
                 )
-                (call $_pop_arg_336
-                  (i32.add
-                    (get_local $3)
-                    (i32.shl
-                      (get_local $0)
-                      (i32.const 3)
+                (block
+                  (nop)
+                  (call $_pop_arg_336
+                    (i32.add
+                      (get_local $3)
+                      (i32.shl
+                        (get_local $0)
+                        (i32.const 3)
+                      )
                     )
+                    (get_local $1)
+                    (get_local $2)
                   )
-                  (get_local $1)
-                  (get_local $2)
-                )
-                (br_if $while-in130
-                  (i32.lt_s
-                    (tee_local $0
-                      (i32.add
-                        (get_local $0)
-                        (i32.const 1)
+                  (br_if $while-in130
+                    (i32.lt_s
+                      (tee_local $0
+                        (i32.add
+                          (get_local $0)
+                          (i32.const 1)
+                        )
                       )
+                      (i32.const 10)
                     )
-                    (i32.const 10)
                   )
-                )
-                (block
-                  (set_local $16
-                    (i32.const 1)
+                  (block
+                    (set_local $16
+                      (i32.const 1)
+                    )
+                    (br $label$break$L343)
                   )
-                  (br $label$break$L343)
                 )
               )
             )
@@ -15686,48 +15689,46 @@
       )
       (block
         (loop $while-in
-          (block $while-out
-            (br_if $while-out
-              (i32.eqz
-                (i32.and
-                  (get_local $0)
-                  (i32.const 3)
-                )
-              )
-            )
-            (if
-              (i32.eqz
-                (get_local $2)
-              )
-              (return
-                (get_local $3)
-              )
-            )
-            (i32.store8
+          (if
+            (i32.and
               (get_local $0)
-              (i32.load8_s
-                (get_local $1)
-              )
+              (i32.const 3)
             )
-            (set_local $0
-              (i32.add
+            (block
+              (if
+                (i32.eqz
+                  (get_local $2)
+                )
+                (return
+                  (get_local $3)
+                )
+              )
+              (i32.store8
                 (get_local $0)
-                (i32.const 1)
+                (i32.load8_s
+                  (get_local $1)
+                )
               )
-            )
-            (set_local $1
-              (i32.add
-                (get_local $1)
-                (i32.const 1)
+              (set_local $0
+                (i32.add
+                  (get_local $0)
+                  (i32.const 1)
+                )
               )
-            )
-            (set_local $2
-              (i32.sub
-                (get_local $2)
-                (i32.const 1)
+              (set_local $1
+                (i32.add
+                  (get_local $1)
+                  (i32.const 1)
+                )
+              )
+              (set_local $2
+                (i32.sub
+                  (get_local $2)
+                  (i32.const 1)
+                )
               )
+              (br $while-in)
             )
-            (br $while-in)
           )
         )
         (loop $while-in1
diff --git a/test/memorygrowth.fromasm b/test/memorygrowth.fromasm
index d2c814e8d..48b09d9c3 100644
--- a/test/memorygrowth.fromasm
+++ b/test/memorygrowth.fromasm
@@ -9052,48 +9052,46 @@
       )
       (block
         (loop $while-in
-          (block $while-out
-            (br_if $while-out
-              (i32.eqz
-                (i32.and
-                  (get_local $0)
-                  (i32.const 3)
-                )
-              )
-            )
-            (if
-              (i32.eqz
-                (get_local $2)
-              )
-              (return
-                (get_local $3)
-              )
-            )
-            (i32.store8
+          (if
+            (i32.and
               (get_local $0)
-              (i32.load8_s
-                (get_local $1)
-              )
+              (i32.const 3)
             )
-            (set_local $0
-              (i32.add
+            (block
+              (if
+                (i32.eqz
+                  (get_local $2)
+                )
+                (return
+                  (get_local $3)
+                )
+              )
+              (i32.store8
                 (get_local $0)
-                (i32.const 1)
+                (i32.load8_s
+                  (get_local $1)
+                )
               )
-            )
-            (set_local $1
-              (i32.add
-                (get_local $1)
-                (i32.const 1)
+              (set_local $0
+                (i32.add
+                  (get_local $0)
+                  (i32.const 1)
+                )
               )
-            )
-            (set_local $2
-              (i32.sub
-                (get_local $2)
-                (i32.const 1)
+              (set_local $1
+                (i32.add
+                  (get_local $1)
+                  (i32.const 1)
+                )
               )
+              (set_local $2
+                (i32.sub
+                  (get_local $2)
+                  (i32.const 1)
+                )
+              )
+              (br $while-in)
             )
-            (br $while-in)
           )
         )
         (loop $while-in1
diff --git a/test/memorygrowth.fromasm.imprecise b/test/memorygrowth.fromasm.imprecise
index f9fa51bce..f509f23f2 100644
--- a/test/memorygrowth.fromasm.imprecise
+++ b/test/memorygrowth.fromasm.imprecise
@@ -9050,48 +9050,46 @@
       )
       (block
         (loop $while-in
-          (block $while-out
-            (br_if $while-out
-              (i32.eqz
-                (i32.and
-                  (get_local $0)
-                  (i32.const 3)
-                )
-              )
-            )
-            (if
-              (i32.eqz
-                (get_local $2)
-              )
-              (return
-                (get_local $3)
-              )
-            )
-            (i32.store8
+          (if
+            (i32.and
               (get_local $0)
-              (i32.load8_s
-                (get_local $1)
-              )
+              (i32.const 3)
             )
-            (set_local $0
-              (i32.add
+            (block
+              (if
+                (i32.eqz
+                  (get_local $2)
+                )
+                (return
+                  (get_local $3)
+                )
+              )
+              (i32.store8
                 (get_local $0)
-                (i32.const 1)
+                (i32.load8_s
+                  (get_local $1)
+                )
               )
-            )
-            (set_local $1
-              (i32.add
-                (get_local $1)
-                (i32.const 1)
+              (set_local $0
+                (i32.add
+                  (get_local $0)
+                  (i32.const 1)
+                )
               )
-            )
-            (set_local $2
-              (i32.sub
-                (get_local $2)
-                (i32.const 1)
+              (set_local $1
+                (i32.add
+                  (get_local $1)
+                  (i32.const 1)
+                )
               )
+              (set_local $2
+                (i32.sub
+                  (get_local $2)
+                  (i32.const 1)
+                )
+              )
+              (br $while-in)
             )
-            (br $while-in)
           )
         )
         (loop $while-in1
diff --git a/test/passes/remove-unused-brs.txt b/test/passes/remove-unused-brs.txt
index ab3260a4b..b95ace90d 100644
--- a/test/passes/remove-unused-brs.txt
+++ b/test/passes/remove-unused-brs.txt
@@ -458,12 +458,15 @@
       )
     )
     (loop $in39
-      (block $out40
-        (br_if $out40
+      (if
+        (i32.eqz
           (i32.const 0)
         )
-        (br_if $in39
-          (i32.const 1)
+        (block
+          (nop)
+          (br_if $in39
+            (i32.const 1)
+          )
         )
       )
     )
@@ -595,13 +598,16 @@
       )
     )
     (loop $in72
-      (block $out73
-        (br_if $out73
+      (if
+        (i32.eqz
           (i32.const 0)
         )
-        (call $loops)
-        (return)
-        (br $in72)
+        (block
+          (nop)
+          (call $loops)
+          (return)
+          (br $in72)
+        )
       )
     )
     (loop $in75
@@ -876,4 +882,59 @@
       )
     )
   )
+  (func $iffify (type $1)
+    (if
+      (i32.eqz
+        (i32.const 0)
+      )
+      (block
+        (nop)
+        (drop
+          (i32.const 1)
+        )
+        (drop
+          (i32.const 2)
+        )
+      )
+    )
+    (block $no
+      (br_if $no
+        (i32.const 0)
+      )
+      (drop
+        (i32.const 1)
+      )
+      (br $no)
+      (drop
+        (i32.const 2)
+      )
+    )
+    (block $no2
+      (br_if $no2
+        (i32.const 0)
+      )
+    )
+    (block $no3
+      (br $no3)
+      (drop
+        (i32.const 1)
+      )
+      (drop
+        (i32.const 2)
+      )
+    )
+    (block $no5
+      (block $no4
+        (br_if $no5
+          (i32.const 0)
+        )
+        (drop
+          (i32.const 1)
+        )
+        (drop
+          (i32.const 2)
+        )
+      )
+    )
+  )
 )
diff --git a/test/passes/remove-unused-brs.wast b/test/passes/remove-unused-brs.wast
index 7a401b893..8b0ad357b 100644
--- a/test/passes/remove-unused-brs.wast
+++ b/test/passes/remove-unused-brs.wast
@@ -795,5 +795,41 @@
       )
     )
   )
+  (func $iffify
+    (block $yes
+      (br_if $yes
+        (i32.const 0)
+      )
+      (drop (i32.const 1))
+      (drop (i32.const 2))
+    )
+    (block $no
+      (br_if $no
+        (i32.const 0)
+      )
+      (drop (i32.const 1))
+      (br $no)
+      (drop (i32.const 2))
+    )
+    (block $no2
+      (br_if $no2
+        (i32.const 0)
+      )
+    )
+    (block $no3
+      (br $no3)
+      (drop (i32.const 1))
+      (drop (i32.const 2))
+    )
+    (block $no5
+      (block $no4
+        (br_if $no5
+          (i32.const 0)
+        )
+        (drop (i32.const 1))
+        (drop (i32.const 2))
+      )
+    )
+  )
 )
 
diff --git a/test/passes/remove-unused-brs_shrink-level=1.txt b/test/passes/remove-unused-brs_shrink-level=1.txt
index 0356cc1da..68015f73f 100644
--- a/test/passes/remove-unused-brs_shrink-level=1.txt
+++ b/test/passes/remove-unused-brs_shrink-level=1.txt
@@ -16,4 +16,82 @@
       )
     )
   )
+  (func $join-br_ifs (type $1)
+    (block $out
+      (br_if $out
+        (i32.or
+          (i32.const 1)
+          (i32.const 2)
+        )
+      )
+      (nop)
+      (br_if $out
+        (i32.const 3)
+      )
+    )
+    (block $out2
+      (block $out3
+        (br_if $out2
+          (i32.const 1)
+        )
+        (br_if $out3
+          (i32.const 2)
+        )
+        (br_if $out2
+          (i32.const 3)
+        )
+      )
+      (unreachable)
+    )
+    (block $out4
+      (block $out5
+        (br_if $out4
+          (i32.const 1)
+        )
+        (br_if $out5
+          (i32.or
+            (i32.const 2)
+            (i32.const 3)
+          )
+        )
+        (nop)
+      )
+      (unreachable)
+    )
+    (block $out6
+      (block $out7
+        (br_if $out6
+          (i32.or
+            (i32.const 1)
+            (i32.const 2)
+          )
+        )
+        (nop)
+        (br_if $out7
+          (i32.const 3)
+        )
+      )
+      (unreachable)
+    )
+    (if
+      (i32.eqz
+        (i32.or
+          (call $b14)
+          (i32.const 0)
+        )
+      )
+      (block
+        (nop)
+        (nop)
+      )
+    )
+    (block $out80
+      (br_if $out80
+        (i32.const 1)
+      )
+      (br_if $out80
+        (call $b14)
+      )
+    )
+  )
 )
diff --git a/test/passes/remove-unused-brs_shrink-level=1.wast b/test/passes/remove-unused-brs_shrink-level=1.wast
index 9698bd899..5a2234de6 100644
--- a/test/passes/remove-unused-brs_shrink-level=1.wast
+++ b/test/passes/remove-unused-brs_shrink-level=1.wast
@@ -16,5 +16,44 @@
       )
     )
   )
+  (func $join-br_ifs
+    (block $out
+      (br_if $out (i32.const 1))
+      (br_if $out (i32.const 2))
+      (br_if $out (i32.const 3))
+    )
+    (block $out2
+      (block $out3
+        (br_if $out2 (i32.const 1))
+        (br_if $out3 (i32.const 2))
+        (br_if $out2 (i32.const 3))
+      )
+      (unreachable)
+    )
+    (block $out4
+      (block $out5
+        (br_if $out4 (i32.const 1))
+        (br_if $out5 (i32.const 2))
+        (br_if $out5 (i32.const 3))
+      )
+      (unreachable)
+    )
+    (block $out6
+      (block $out7
+        (br_if $out6 (i32.const 1))
+        (br_if $out6 (i32.const 2))
+        (br_if $out7 (i32.const 3))
+      )
+      (unreachable)
+    )
+    (block $out8
+      (br_if $out8 (call $b14)) ;; side effect
+      (br_if $out8 (i32.const 0))
+    )
+    (block $out8
+      (br_if $out8 (i32.const 1))
+      (br_if $out8 (call $b14)) ;; side effect
+    )
+  )
 )