From 8b5a6171af0f9e434711b8a9bd2f217994a810de Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Wed, 4 Jun 2025 11:28:12 +0800
Subject: [PATCH 01/27] opt for #7637

---
 src/passes/RemoveUnusedBrs.cpp | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index 6f20cfd63af..159197a9cd1 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -24,6 +24,7 @@
 #include "ir/effects.h"
 #include "ir/gc-type-utils.h"
 #include "ir/literal-utils.h"
+#include "ir/properties.h"
 #include "ir/utils.h"
 #include "parsing.h"
 #include "pass.h"
@@ -1881,6 +1882,23 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
           start = end;
         }
       }
+
+      void visitBreak(Break* curr) {
+        if (!curr->condition) {
+          return;
+        }
+        // optimize if condition's fallthrough is a constant
+        auto* value = Properties::getFallthrough(
+          curr->condition, passOptions, *getModule());
+        if (auto* c = value->dynCast<Const>()) {
+          curr->condition = getDroppedChildrenAndAppend(
+            curr->condition,
+            *getModule(),
+            passOptions,
+            Builder(*getModule()).makeConst(c->value),
+            DropMode::NoticeParentEffects);
+        }
+      }
     };
     FinalOptimizer finalOptimizer(getPassOptions());
     finalOptimizer.setModule(getModule());

From b9db9cf1a52e65ab7c57fe7763854f0b852b7570 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Wed, 4 Jun 2025 11:28:20 +0800
Subject: [PATCH 02/27] tests

---
 test/lit/passes/remove-unused-brs.wast              | 7 ++++++-
 test/passes/remove-unused-brs_enable-multivalue.txt | 7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/test/lit/passes/remove-unused-brs.wast b/test/lit/passes/remove-unused-brs.wast
index ed7fd168148..9b0a12063bd 100644
--- a/test/lit/passes/remove-unused-brs.wast
+++ b/test/lit/passes/remove-unused-brs.wast
@@ -472,7 +472,12 @@
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (br_if $block
   ;; CHECK-NEXT:     (local.get $temp)
-  ;; CHECK-NEXT:     (local.tee $temp
+  ;; CHECK-NEXT:     (block (result i32)
+  ;; CHECK-NEXT:      (drop
+  ;; CHECK-NEXT:       (local.tee $temp
+  ;; CHECK-NEXT:        (i32.const 1)
+  ;; CHECK-NEXT:       )
+  ;; CHECK-NEXT:      )
   ;; CHECK-NEXT:      (i32.const 1)
   ;; CHECK-NEXT:     )
   ;; CHECK-NEXT:    )
diff --git a/test/passes/remove-unused-brs_enable-multivalue.txt b/test/passes/remove-unused-brs_enable-multivalue.txt
index a20f2905bf0..d3c5c40d464 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.txt
+++ b/test/passes/remove-unused-brs_enable-multivalue.txt
@@ -2897,7 +2897,12 @@
     (i32.const 1026)
     (then
      (br_if $label$1
-      (local.tee $0
+      (block (result i32)
+       (drop
+        (local.tee $0
+         (i32.const -7)
+        )
+       )
        (i32.const -7)
       )
      )

From 223bfc0607a9c74da747f1a461da2bd7ff45126f Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Wed, 4 Jun 2025 13:23:36 +0800
Subject: [PATCH 03/27] add a test

---
 test/lit/passes/remove-unused-brs.wast | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/test/lit/passes/remove-unused-brs.wast b/test/lit/passes/remove-unused-brs.wast
index 9b0a12063bd..aa067049ff6 100644
--- a/test/lit/passes/remove-unused-brs.wast
+++ b/test/lit/passes/remove-unused-brs.wast
@@ -340,6 +340,31 @@
     )
   )
 
+  ;; CHECK:      (func $restructure-br_if-value-effectful-corner-case-5 (type $5) (param $x i32)
+  ;; CHECK-NEXT:  (block $x
+  ;; CHECK-NEXT:   (br_if $x
+  ;; CHECK-NEXT:    (block (result i32)
+  ;; CHECK-NEXT:     (drop
+  ;; CHECK-NEXT:      (local.tee $x
+  ;; CHECK-NEXT:       (i32.const 1)
+  ;; CHECK-NEXT:      )
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:     (i32.const 1)
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $restructure-br_if-value-effectful-corner-case-5 (param $x i32)
+    (block $x
+      (br_if $x
+        (local.tee $x
+          (i32.const 1)
+        )
+      )
+    )
+  )
+
+
   ;; CHECK:      (func $restructure-br_if-value-redundant-in-block-tail-1 (type $2) (result i32)
   ;; CHECK-NEXT:  (block $parent (result i32)
   ;; CHECK-NEXT:   (call $nothing)

From 1f44ad6757213555dbe66762f18654bc3cf5de5c Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Wed, 4 Jun 2025 15:24:36 +0800
Subject: [PATCH 04/27] Add comments

---
 test/lit/passes/remove-unused-brs.wast | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/test/lit/passes/remove-unused-brs.wast b/test/lit/passes/remove-unused-brs.wast
index aa067049ff6..481b429660c 100644
--- a/test/lit/passes/remove-unused-brs.wast
+++ b/test/lit/passes/remove-unused-brs.wast
@@ -357,6 +357,8 @@
   (func $restructure-br_if-value-effectful-corner-case-5 (param $x i32)
     (block $x
       (br_if $x
+        ;; the fallthrough of the condition is constant,
+        ;; we can infer how the branch happens and apply that
         (local.tee $x
           (i32.const 1)
         )

From 1feb9ca812746981349502c4dcc55f5a6106158d Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Thu, 5 Jun 2025 11:40:23 +0800
Subject: [PATCH 05/27] Use ChildLocalizer if there is no curr->value

---
 src/passes/RemoveUnusedBrs.cpp | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index 159197a9cd1..8f758183171 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -24,6 +24,7 @@
 #include "ir/effects.h"
 #include "ir/gc-type-utils.h"
 #include "ir/literal-utils.h"
+#include "ir/localize.h"
 #include "ir/properties.h"
 #include "ir/utils.h"
 #include "parsing.h"
@@ -1887,16 +1888,32 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
         if (!curr->condition) {
           return;
         }
-        // optimize if condition's fallthrough is a constant
         auto* value = Properties::getFallthrough(
           curr->condition, passOptions, *getModule());
+        // optimize if condition's fallthrough is a constant
         if (auto* c = value->dynCast<Const>()) {
-          curr->condition = getDroppedChildrenAndAppend(
-            curr->condition,
-            *getModule(),
-            passOptions,
-            Builder(*getModule()).makeConst(c->value),
-            DropMode::NoticeParentEffects);
+          curr->dump();
+          if (curr->value) {
+            curr->condition = getDroppedChildrenAndAppend(
+              curr->condition,
+              *getModule(),
+              passOptions,
+              Builder(*getModule()).makeConst(c->value),
+              DropMode::NoticeParentEffects);
+          } else {
+            ChildLocalizer localizer(
+              curr, getFunction(), *getModule(), passOptions);
+            auto* block = localizer.getChildrenReplacement();
+            if (c->value.geti32()) {
+              // the branch is always taken, make it unconditional
+              curr->condition = nullptr;
+              block->list.push_back(curr);
+              replaceCurrent(block);
+            } else {
+              // the branch is never taken, allow control flow to fall through
+              replaceCurrent(block);
+            }
+          }
         }
       }
     };

From df10dcee303aecdb5bc0b2df695003c7796870ee Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Thu, 5 Jun 2025 11:40:38 +0800
Subject: [PATCH 06/27] Update test

---
 test/lit/passes/remove-unused-brs.wast | 58 ++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 7 deletions(-)

diff --git a/test/lit/passes/remove-unused-brs.wast b/test/lit/passes/remove-unused-brs.wast
index 481b429660c..c5c18c54391 100644
--- a/test/lit/passes/remove-unused-brs.wast
+++ b/test/lit/passes/remove-unused-brs.wast
@@ -340,30 +340,74 @@
     )
   )
 
-  ;; CHECK:      (func $restructure-br_if-value-effectful-corner-case-5 (type $5) (param $x i32)
-  ;; CHECK-NEXT:  (block $x
+  ;; CHECK:      (func $restructure-br_if-constant-branch-1 (type $0) (param $x i32) (result i32)
+  ;; CHECK-NEXT:  (block $x (result i32)
   ;; CHECK-NEXT:   (br_if $x
+  ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:    (block (result i32)
   ;; CHECK-NEXT:     (drop
   ;; CHECK-NEXT:      (local.tee $x
-  ;; CHECK-NEXT:       (i32.const 1)
+  ;; CHECK-NEXT:       (i32.const 42)
   ;; CHECK-NEXT:      )
   ;; CHECK-NEXT:     )
-  ;; CHECK-NEXT:     (i32.const 1)
+  ;; CHECK-NEXT:     (i32.const 42)
   ;; CHECK-NEXT:    )
   ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (unreachable)
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT: )
-  (func $restructure-br_if-value-effectful-corner-case-5 (param $x i32)
+  (func $restructure-br_if-constant-branch-1 (param $x i32) (result i32)
+    (block $x (result i32)
+      (br_if $x
+        (unreachable)
+        (local.tee $x
+          (i32.const 42)
+        )
+      )
+      (unreachable)
+    )
+  )
+  ;; CHECK:      (func $restructure-br_if-constant-branch-2 (type $5) (param $x i32)
+  ;; CHECK-NEXT:  (local $1 i32)
+  ;; CHECK-NEXT:  (local $2 i32)
+  ;; CHECK-NEXT:  (block $x
+  ;; CHECK-NEXT:   (block
+  ;; CHECK-NEXT:    (local.set $1
+  ;; CHECK-NEXT:     (local.tee $x
+  ;; CHECK-NEXT:      (i32.const 1)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:    (br $x)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (block $x0
+  ;; CHECK-NEXT:   (block
+  ;; CHECK-NEXT:    (local.set $2
+  ;; CHECK-NEXT:     (local.tee $x
+  ;; CHECK-NEXT:      (i32.const 0)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $restructure-br_if-constant-branch-2 (param $x i32)
+    ;; there is no value, thus it can be simpler as below
     (block $x
       (br_if $x
-        ;; the fallthrough of the condition is constant,
-        ;; we can infer how the branch happens and apply that
+        ;; the branch is always taken, make it unconditional
         (local.tee $x
           (i32.const 1)
         )
       )
     )
+    (block $x
+      (br_if $x
+        ;; the branch is never taken, allow control flow to fall through
+        (local.tee $x
+          (i32.const 0)
+        )
+      )
+    )
   )
 
 

From bae974971d79424fa55e9d5eede4bb32cfc5bea8 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Thu, 5 Jun 2025 14:17:09 +0800
Subject: [PATCH 07/27] NFC

---
 src/passes/RemoveUnusedBrs.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index 8f758183171..f41ed2913bc 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -1892,7 +1892,6 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
           curr->condition, passOptions, *getModule());
         // optimize if condition's fallthrough is a constant
         if (auto* c = value->dynCast<Const>()) {
-          curr->dump();
           if (curr->value) {
             curr->condition = getDroppedChildrenAndAppend(
               curr->condition,

From 6eafa8c390b183910f34b8abd13312cc9efc4925 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Thu, 5 Jun 2025 14:17:21 +0800
Subject: [PATCH 08/27] Bugfix

---
 src/passes/RemoveUnusedBrs.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index f41ed2913bc..dd8da4efd37 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -1906,7 +1906,9 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
             if (c->value.geti32()) {
               // the branch is always taken, make it unconditional
               curr->condition = nullptr;
+              curr->type = Type::unreachable;
               block->list.push_back(curr);
+              block->finalize();
               replaceCurrent(block);
             } else {
               // the branch is never taken, allow control flow to fall through

From 3dacea0bf769dbb8a6215c29be8d545d291a838d Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Fri, 6 Jun 2025 16:57:02 +0800
Subject: [PATCH 09/27] refinalize the type

---
 src/passes/RemoveUnusedBrs.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index dd8da4efd37..2c911f41239 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -1909,6 +1909,8 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
               curr->type = Type::unreachable;
               block->list.push_back(curr);
               block->finalize();
+              // the type is changed , so refinalize
+              refinalize = true;
               replaceCurrent(block);
             } else {
               // the branch is never taken, allow control flow to fall through

From e41f3443616c2686f60e965af5901d8305339ca7 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Fri, 6 Jun 2025 17:30:17 +0800
Subject: [PATCH 10/27] Add test of two-branches-unreachable

---
 test/lit/passes/O1.wast | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/test/lit/passes/O1.wast b/test/lit/passes/O1.wast
index 49271699d73..846686dd5cc 100644
--- a/test/lit/passes/O1.wast
+++ b/test/lit/passes/O1.wast
@@ -4,6 +4,8 @@
 ;; RUN: foreach %s %t wasm-opt -O1 -S -o - | filecheck %s
 
 (module
+
+ (import "env" "fimport$0" (func $fimport$0 (param i32)))
  ;; CHECK:      (type $0 (func (result i32)))
 
  ;; CHECK:      (memory $0 1 1)
@@ -38,5 +40,37 @@
    (i32.const -2147483648)
   )
  )
+ (func $two-branches-unreachable
+  ;; remove-unused-brs makes the break unconditional,
+  ;; thus in this case the two branches are unreachable,
+  ;; refinalization is required.
+  (local $0 i32)
+  (block $label
+   (block $block
+    (if
+     (local.get $0)
+     (then
+      (if
+       (local.tee $0
+        (i32.const 1)
+       )
+       (then
+        (br $label)
+       )
+       (else
+        (br $block)
+       )
+      )
+     )
+     (else
+      (unreachable)
+     )
+    )
+   )
+   (call $fimport$0
+    (local.get $0)
+   )
+  )
+ )
 )
 

From abbe4ce63e15e467ec82609aa060bbadf9c1c9dd Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Fri, 6 Jun 2025 17:52:46 +0800
Subject: [PATCH 11/27] Use auto_update script

---
 .../remove-unused-brs_enable-multivalue.txt   | 141 +++++++-----------
 .../remove-unused-brs_shrink-level=1.txt      |  75 +++++-----
 ...s_shrink-level=1_ignore-implicit-traps.txt |  69 ++++-----
 3 files changed, 123 insertions(+), 162 deletions(-)

diff --git a/test/passes/remove-unused-brs_enable-multivalue.txt b/test/passes/remove-unused-brs_enable-multivalue.txt
index d3c5c40d464..8e7881785c1 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.txt
+++ b/test/passes/remove-unused-brs_enable-multivalue.txt
@@ -62,8 +62,8 @@
  )
  (func $b6 (param $i1 i32)
   (block $topmost
-   (br_if $topmost
-    (i32.const 1)
+   (block
+    (br $topmost)
    )
   )
  )
@@ -73,8 +73,8 @@
     (drop
      (i32.const 0)
     )
-    (br_if $topmost
-     (i32.const 1)
+    (block
+     (br $topmost)
     )
    )
   )
@@ -82,8 +82,8 @@
  (func $b8 (param $i1 i32)
   (block $topmost
    (block $inner
-    (br_if $topmost
-     (i32.const 1)
+    (block
+     (br $topmost)
     )
    )
   )
@@ -91,8 +91,8 @@
  (func $b9 (param $i1 i32)
   (block $topmost
    (block $inner
-    (br_if $topmost
-     (i32.const 1)
+    (block
+     (br $topmost)
     )
    )
   )
@@ -104,8 +104,8 @@
      (drop
       (i32.const 0)
      )
-     (br_if $topmost
-      (i32.const 1)
+     (block
+      (br $topmost)
      )
     )
    )
@@ -118,8 +118,8 @@
      (drop
       (i32.const 0)
      )
-     (br_if $topmost
-      (i32.const 1)
+     (block
+      (br $topmost)
      )
     )
    )
@@ -225,8 +225,8 @@
  )
  (func $b15
   (block $topmost
-   (br_if $topmost
-    (i32.const 17)
+   (block
+    (br $topmost)
    )
   )
  )
@@ -516,15 +516,13 @@
   )
   (loop
    (block $out0
-    (br_if $out0
-     (i32.const 0)
+    (block
     )
    )
   )
   (loop $in1
    (block $out1
-    (br_if $out1
-     (i32.const 0)
+    (block
     )
    )
   )
@@ -535,24 +533,17 @@
    )
   )
   (loop $in4
-   (if
-    (i32.eqz
-     (i32.const 0)
+   (block $out3
+    (block
     )
-    (then
-     (block $out3
-      (nop)
-      (br_if $in4
-       (i32.const 1)
-      )
-     )
+    (block
+     (br $in4)
     )
    )
   )
   (loop $in5
    (block $out4
-    (br_if $in5
-     (i32.const 0)
+    (block
     )
    )
   )
@@ -763,19 +754,17 @@
   )
   (loop $in19
    (block $out18
-    (drop
-     (i32.const 0)
+    (block
     )
     (br $in19)
    )
   )
   (loop $in-not
    (block $out-not
-    (br_if $out-not
-     (i32.const -1)
+    (block
+     (br $out-not)
     )
-    (br_if $out-not
-     (i32.const 0)
+    (block
     )
     (call $loops)
     (br $in-not)
@@ -838,11 +827,11 @@
     (block $value-in (result i32)
      (block $out
       (block $in
-       (br_if $out
-        (i32.const 1)
+       (block
+        (br $out)
        )
-       (br_if $out
-        (i32.const 2)
+       (block
+        (br $out)
        )
        (br $value-in
         (i32.const 3)
@@ -857,8 +846,8 @@
    (block $stack2
     (block $stack3
      (block $stack4
-      (br_if $stack1
-       (i32.const 1)
+      (block
+       (br $stack1)
       )
       (unreachable)
      )
@@ -883,9 +872,7 @@
        )
       )
       (else
-       (br_if $leave
-        (i32.const 1)
-       )
+       (br $leave)
       )
      )
      (unreachable)
@@ -904,9 +891,7 @@
      (if
       (local.get $x)
       (then
-       (br_if $leave
-        (i32.const 1)
-       )
+       (br $leave)
       )
       (else
        (br $out
@@ -993,25 +978,18 @@
   )
  )
  (func $iffify
-  (if
-   (i32.eqz
-    (i32.const 0)
+  (block $yes
+   (block
    )
-   (then
-    (block $yes
-     (nop)
-     (drop
-      (i32.const 1)
-     )
-     (drop
-      (i32.const 2)
-     )
-    )
+   (drop
+    (i32.const 1)
+   )
+   (drop
+    (i32.const 2)
    )
   )
   (block $no
-   (br_if $no
-    (i32.const 0)
+   (block
    )
    (drop
     (i32.const 1)
@@ -1022,8 +1000,7 @@
    )
   )
   (block $no2
-   (br_if $no2
-    (i32.const 0)
+   (block
    )
   )
   (block $no3
@@ -1037,8 +1014,7 @@
   )
   (block $no5
    (block $no4
-    (br_if $no5
-     (i32.const 0)
+    (block
     )
     (drop
      (i32.const 1)
@@ -1094,22 +1070,24 @@
  (func $untaken-brs-might-prevent-block-removal (param $0 f32) (param $1 i32) (param $2 f32) (param $3 i32) (param $4 i32) (param $5 f64) (param $6 f32) (result i32)
   (block $label$0 (result i32)
    (block $label$1
-    (br_if $label$1
-     (i32.const 607395945)
+    (block
+     (br $label$1)
     )
     (br_if $label$1
      (i32.load offset=3 align=1
       (select
        (call $untaken-brs-might-prevent-block-removal
         (f32.const 1.4904844647389837e-07)
-        (br_if $label$0
+        (block
          (i32.store16 offset=4 align=1
           (i32.const 1900641)
           (br $label$0
            (i32.const 1628075109)
           )
          )
-         (i32.const 1764950569)
+         (drop
+          (i32.const 1764950569)
+         )
         )
         (f32.const 1.1910939690100655e-32)
         (i32.const 1628057906)
@@ -1925,8 +1903,7 @@
  )
  (func $same-target-br_if-and-br
   (block $x
-   (drop
-    (i32.const 0)
+   (block
    )
    (br $x)
    (unreachable)
@@ -2313,8 +2290,8 @@
  )
  (func $if-block-br
   (block $label
-   (br_if $label
-    (i32.const 1)
+   (block
+    (br $label)
    )
   )
  )
@@ -2538,8 +2515,7 @@
      (block $label$503
       (br_if $label$3
        (block $label$530 (result i32)
-        (br_if $label$503
-         (i32.const 0)
+        (block
         )
         (i32.const 0)
        )
@@ -2861,6 +2837,7 @@
  )
  (func $if_br_if
   (local $0 i32)
+  (local $1 i32)
   (block $label$1
    (br_if $label$1
     (select
@@ -2896,16 +2873,12 @@
    (if
     (i32.const 1026)
     (then
-     (br_if $label$1
-      (block (result i32)
-       (drop
-        (local.tee $0
-         (i32.const -7)
-        )
-       )
+     (local.set $1
+      (local.tee $0
        (i32.const -7)
       )
      )
+     (br $label$1)
     )
    )
    (i32.store
diff --git a/test/passes/remove-unused-brs_shrink-level=1.txt b/test/passes/remove-unused-brs_shrink-level=1.txt
index 24696cb8355..c3d7fc4e6c5 100644
--- a/test/passes/remove-unused-brs_shrink-level=1.txt
+++ b/test/passes/remove-unused-brs_shrink-level=1.txt
@@ -54,78 +54,73 @@
  )
  (func $join-br_ifs
   (block $out
-   (br_if $out
-    (i32.or
-     (i32.const 1)
-     (i32.const 2)
-    )
+   (block
+    (br $out)
    )
-   (nop)
-   (br_if $out
-    (i32.const 3)
+   (block
+    (br $out)
+   )
+   (block
+    (br $out)
    )
   )
   (block $out2
    (block $out3
-    (br_if $out2
-     (i32.const 1)
+    (block
+     (br $out2)
     )
-    (br_if $out3
-     (i32.const 2)
+    (block
+     (br $out3)
     )
-    (br_if $out2
-     (i32.const 3)
+    (block
+     (br $out2)
     )
    )
    (unreachable)
   )
   (block $out4
    (block $out5
-    (br_if $out4
-     (i32.const 1)
+    (block
+     (br $out4)
     )
-    (br_if $out5
-     (i32.or
-      (i32.const 2)
-      (i32.const 3)
-     )
+    (block
+     (br $out5)
+    )
+    (block
+     (br $out5)
     )
-    (nop)
    )
    (unreachable)
   )
   (block $out6
    (block $out7
-    (br_if $out6
-     (i32.or
-      (i32.const 1)
-      (i32.const 2)
-     )
+    (block
+     (br $out6)
+    )
+    (block
+     (br $out6)
     )
-    (nop)
-    (br_if $out7
-     (i32.const 3)
+    (block
+     (br $out7)
     )
    )
    (unreachable)
   )
   (if
    (i32.eqz
-    (i32.or
-     (call $b14)
-     (i32.const 0)
-    )
+    (call $b14)
    )
    (then
     (block $out8
      (nop)
-     (nop)
+     (block
+     )
     )
    )
   )
   (block $out80
-   (br_if $out80
-    (i32.const 1)
+   (block
+    (br $out80)
    )
    (br_if $out80
     (call $b14)
@@ -153,15 +148,13 @@
    (br_if $label$14
     (unreachable)
    )
-   (br_if $label$14
-    (i32.const 0)
+   (block
    )
   )
  )
  (func $br-if-unreachable-pair2
   (block $label$14
-   (br_if $label$14
-    (i32.const 0)
+   (block
    )
    (br_if $label$14
     (unreachable)
diff --git a/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.txt b/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.txt
index 82f76d359c7..01c913eacab 100644
--- a/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.txt
+++ b/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.txt
@@ -46,78 +46,73 @@
  )
  (func $join-br_ifs
   (block $out
-   (br_if $out
-    (i32.or
-     (i32.const 1)
-     (i32.const 2)
-    )
+   (block
+    (br $out)
+   )
+   (block
+    (br $out)
    )
-   (nop)
-   (br_if $out
-    (i32.const 3)
+   (block
+    (br $out)
    )
   )
   (block $out2
    (block $out3
-    (br_if $out2
-     (i32.const 1)
+    (block
+     (br $out2)
     )
-    (br_if $out3
-     (i32.const 2)
+    (block
+     (br $out3)
     )
-    (br_if $out2
-     (i32.const 3)
+    (block
+     (br $out2)
     )
    )
    (unreachable)
   )
   (block $out4
    (block $out5
-    (br_if $out4
-     (i32.const 1)
+    (block
+     (br $out4)
     )
-    (br_if $out5
-     (i32.or
-      (i32.const 2)
-      (i32.const 3)
-     )
+    (block
+     (br $out5)
+    )
+    (block
+     (br $out5)
     )
-    (nop)
    )
    (unreachable)
   )
   (block $out6
    (block $out7
-    (br_if $out6
-     (i32.or
-      (i32.const 1)
-      (i32.const 2)
-     )
+    (block
+     (br $out6)
+    )
+    (block
+     (br $out6)
     )
-    (nop)
-    (br_if $out7
-     (i32.const 3)
+    (block
+     (br $out7)
     )
    )
    (unreachable)
   )
   (if
    (i32.eqz
-    (i32.or
-     (call $b14)
-     (i32.const 0)
-    )
+    (call $b14)
    )
    (then
     (block $out8
      (nop)
-     (nop)
+     (block
+     )
     )
    )
   )
   (block $out80
-   (br_if $out80
-    (i32.const 1)
+   (block
+    (br $out80)
    )
    (br_if $out80
     (call $b14)

From 08234b37a1d7a27ff8a9d1fee38e813c36473cc5 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Thu, 12 Jun 2025 08:58:18 +0800
Subject: [PATCH 12/27] Add export to make CHECK lines appear

---
 test/lit/passes/O1.wast | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/test/lit/passes/O1.wast b/test/lit/passes/O1.wast
index 846686dd5cc..099942b2cbf 100644
--- a/test/lit/passes/O1.wast
+++ b/test/lit/passes/O1.wast
@@ -8,11 +8,15 @@
  (import "env" "fimport$0" (func $fimport$0 (param i32)))
  ;; CHECK:      (type $0 (func (result i32)))
 
+ ;; CHECK:      (type $1 (func))
+
  ;; CHECK:      (memory $0 1 1)
  (memory $0 1 1)
  (global $global$0 (mut i32) (i32.const 10))
  ;; CHECK:      (export "foo" (func $foo))
 
+ ;; CHECK:      (export "two-branches-unreachable" (func $two-branches-unreachable))
+
  ;; CHECK:      (func $foo (result i32)
  ;; CHECK-NEXT:  (drop
  ;; CHECK-NEXT:   (i32.const 0)
@@ -40,7 +44,18 @@
    (i32.const -2147483648)
   )
  )
- (func $two-branches-unreachable
+ ;; CHECK:      (func $two-branches-unreachable
+ ;; CHECK-NEXT:  (local $0 i32)
+ ;; CHECK-NEXT:  (if
+ ;; CHECK-NEXT:   (i32.eqz
+ ;; CHECK-NEXT:    (local.get $0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (then
+ ;; CHECK-NEXT:    (unreachable)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $two-branches-unreachable (export "two-branches-unreachable")
   ;; remove-unused-brs makes the break unconditional,
   ;; thus in this case the two branches are unreachable,
   ;; refinalization is required.

From 05f8a1ad60e0f46ca0a76d7cbcdb56736630bf65 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Thu, 12 Jun 2025 10:52:54 +0800
Subject: [PATCH 13/27] work

---
 src/passes/RemoveUnusedBrs.cpp | 38 +++++++++++++++-------------------
 1 file changed, 17 insertions(+), 21 deletions(-)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index 2c911f41239..54a151a557d 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -27,6 +27,7 @@
 #include "ir/localize.h"
 #include "ir/properties.h"
 #include "ir/utils.h"
+#include "literal.h"
 #include "parsing.h"
 #include "pass.h"
 #include "support/small_set.h"
@@ -1892,30 +1893,25 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
           curr->condition, passOptions, *getModule());
         // optimize if condition's fallthrough is a constant
         if (auto* c = value->dynCast<Const>()) {
-          if (curr->value) {
-            curr->condition = getDroppedChildrenAndAppend(
-              curr->condition,
-              *getModule(),
-              passOptions,
-              Builder(*getModule()).makeConst(c->value),
-              DropMode::NoticeParentEffects);
+          ChildLocalizer localizer(
+            curr, getFunction(), *getModule(), passOptions);
+          auto* block = localizer.getChildrenReplacement();
+          if (c->value.geti32()) {
+            // the branch is always taken, make it unconditional
+            curr->condition = nullptr;
+            curr->type = Type::unreachable;
+            block->list.push_back(curr);
+            block->finalize();
+            // the type is changed , so refinalize
+            refinalize = true;
+            replaceCurrent(block);
           } else {
-            ChildLocalizer localizer(
-              curr, getFunction(), *getModule(), passOptions);
-            auto* block = localizer.getChildrenReplacement();
-            if (c->value.geti32()) {
-              // the branch is always taken, make it unconditional
-              curr->condition = nullptr;
-              curr->type = Type::unreachable;
-              block->list.push_back(curr);
+            if (curr->value) {
+              block->list.push_back(curr->value);
               block->finalize();
-              // the type is changed , so refinalize
-              refinalize = true;
-              replaceCurrent(block);
-            } else {
-              // the branch is never taken, allow control flow to fall through
-              replaceCurrent(block);
             }
+            // the branch is never taken, allow control flow to fall through
+            replaceCurrent(block);
           }
         }
       }

From ed25e753342794e6a81699cce4bde3242bad6e04 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Thu, 12 Jun 2025 10:54:25 +0800
Subject: [PATCH 14/27] Update tests

---
 test/lit/passes/remove-unused-brs.wast        | 108 ++++++++++++------
 .../remove-unused-brs_all-features.wast       |  24 ++--
 2 files changed, 84 insertions(+), 48 deletions(-)

diff --git a/test/lit/passes/remove-unused-brs.wast b/test/lit/passes/remove-unused-brs.wast
index c5c18c54391..e73b3bfae42 100644
--- a/test/lit/passes/remove-unused-brs.wast
+++ b/test/lit/passes/remove-unused-brs.wast
@@ -5,7 +5,7 @@
 
 (module
   ;; Regression test in which we need to calculate a proper LUB.
-  ;; CHECK:      (func $selectify-fresh-lub (type $4) (param $x i32) (result anyref)
+  ;; CHECK:      (func $selectify-fresh-lub (type $5) (param $x i32) (result anyref)
   ;; CHECK-NEXT:  (select (result i31ref)
   ;; CHECK-NEXT:   (ref.null none)
   ;; CHECK-NEXT:   (ref.i31
@@ -340,34 +340,63 @@
     )
   )
 
-  ;; CHECK:      (func $restructure-br_if-constant-branch-1 (type $0) (param $x i32) (result i32)
-  ;; CHECK-NEXT:  (block $x (result i32)
-  ;; CHECK-NEXT:   (br_if $x
-  ;; CHECK-NEXT:    (unreachable)
-  ;; CHECK-NEXT:    (block (result i32)
-  ;; CHECK-NEXT:     (drop
-  ;; CHECK-NEXT:      (local.tee $x
-  ;; CHECK-NEXT:       (i32.const 42)
+  ;; CHECK:      (func $restructure-br_if-constant-branch-1 (type $3) (param $x i32)
+  ;; CHECK-NEXT:  (local $1 i32)
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (block $x (result i32)
+  ;; CHECK-NEXT:    (drop
+  ;; CHECK-NEXT:     (block
+  ;; CHECK-NEXT:      (local.set $1
+  ;; CHECK-NEXT:       (local.tee $x
+  ;; CHECK-NEXT:        (i32.const 42)
+  ;; CHECK-NEXT:       )
+  ;; CHECK-NEXT:      )
+  ;; CHECK-NEXT:      (br $x
+  ;; CHECK-NEXT:       (i32.const 10)
   ;; CHECK-NEXT:      )
   ;; CHECK-NEXT:     )
-  ;; CHECK-NEXT:     (i32.const 42)
   ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:    (i32.const 20)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (block $x0 (result i32)
+  ;; CHECK-NEXT:    (drop
+  ;; CHECK-NEXT:     (block (result i32)
+  ;; CHECK-NEXT:      (i32.const 10)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:    )
+  ;; CHECK-NEXT:    (i32.const 20)
   ;; CHECK-NEXT:   )
-  ;; CHECK-NEXT:   (unreachable)
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT: )
-  (func $restructure-br_if-constant-branch-1 (param $x i32) (result i32)
-    (block $x (result i32)
-      (br_if $x
-        (unreachable)
-        (local.tee $x
-          (i32.const 42)
+  (func $restructure-br_if-constant-branch-1 (param $x i32)
+    (drop
+      (block $x (result i32)
+        (drop
+          (br_if $x
+            (i32.const 10)
+            (local.tee $x
+              (i32.const 42)
+            )
+          )
+        )
+        (i32.const 20)
+      )
+    )
+    (drop
+      (block $x (result i32)
+        (drop
+          (br_if $x
+            (i32.const 10)
+            (i32.const 0)
+          )
         )
+        (i32.const 20)
       )
-      (unreachable)
     )
   )
-  ;; CHECK:      (func $restructure-br_if-constant-branch-2 (type $5) (param $x i32)
+  ;; CHECK:      (func $restructure-br_if-constant-branch-2 (type $3) (param $x i32)
   ;; CHECK-NEXT:  (local $1 i32)
   ;; CHECK-NEXT:  (local $2 i32)
   ;; CHECK-NEXT:  (block $x
@@ -539,17 +568,21 @@
 
   ;; CHECK:      (func $restructure-br_if-condition-invalidates-6 (type $2) (result i32)
   ;; CHECK-NEXT:  (local $temp i32)
+  ;; CHECK-NEXT:  (local $1 i32)
+  ;; CHECK-NEXT:  (local $2 i32)
   ;; CHECK-NEXT:  (block $block (result i32)
   ;; CHECK-NEXT:   (drop
-  ;; CHECK-NEXT:    (br_if $block
-  ;; CHECK-NEXT:     (local.get $temp)
-  ;; CHECK-NEXT:     (block (result i32)
-  ;; CHECK-NEXT:      (drop
-  ;; CHECK-NEXT:       (local.tee $temp
-  ;; CHECK-NEXT:        (i32.const 1)
-  ;; CHECK-NEXT:       )
+  ;; CHECK-NEXT:    (block
+  ;; CHECK-NEXT:     (local.set $1
+  ;; CHECK-NEXT:      (local.get $temp)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:     (local.set $2
+  ;; CHECK-NEXT:      (local.tee $temp
+  ;; CHECK-NEXT:       (i32.const 1)
   ;; CHECK-NEXT:      )
-  ;; CHECK-NEXT:      (i32.const 1)
+  ;; CHECK-NEXT:     )
+  ;; CHECK-NEXT:     (br $block
+  ;; CHECK-NEXT:      (local.get $1)
   ;; CHECK-NEXT:     )
   ;; CHECK-NEXT:    )
   ;; CHECK-NEXT:   )
@@ -574,17 +607,22 @@
   )
 
   ;; CHECK:      (func $restructure-select-no-multivalue (type $1)
+  ;; CHECK-NEXT:  (local $0 (tuple i32 i32))
   ;; CHECK-NEXT:  (tuple.drop 2
-  ;; CHECK-NEXT:   (block $block (type $3) (result i32 i32)
-  ;; CHECK-NEXT:    (tuple.drop 2
-  ;; CHECK-NEXT:     (br_if $block
-  ;; CHECK-NEXT:      (tuple.make 2
-  ;; CHECK-NEXT:       (i32.const 1)
-  ;; CHECK-NEXT:       (call $restructure-br_if
-  ;; CHECK-NEXT:        (i32.const 2)
+  ;; CHECK-NEXT:   (block $block (type $4) (result i32 i32)
+  ;; CHECK-NEXT:    (drop
+  ;; CHECK-NEXT:     (block
+  ;; CHECK-NEXT:      (local.set $0
+  ;; CHECK-NEXT:       (tuple.make 2
+  ;; CHECK-NEXT:        (i32.const 1)
+  ;; CHECK-NEXT:        (call $restructure-br_if
+  ;; CHECK-NEXT:         (i32.const 2)
+  ;; CHECK-NEXT:        )
   ;; CHECK-NEXT:       )
   ;; CHECK-NEXT:      )
-  ;; CHECK-NEXT:      (i32.const 3)
+  ;; CHECK-NEXT:      (br $block
+  ;; CHECK-NEXT:       (local.get $0)
+  ;; CHECK-NEXT:      )
   ;; CHECK-NEXT:     )
   ;; CHECK-NEXT:    )
   ;; CHECK-NEXT:    (tuple.make 2
diff --git a/test/lit/passes/remove-unused-brs_all-features.wast b/test/lit/passes/remove-unused-brs_all-features.wast
index e2d89a5ead5..3f971df30e1 100644
--- a/test/lit/passes/remove-unused-brs_all-features.wast
+++ b/test/lit/passes/remove-unused-brs_all-features.wast
@@ -65,22 +65,20 @@
 
  ;; CHECK:      (func $test-prefinalize (type $4) (result f64)
  ;; CHECK-NEXT:  (loop $loop (result f64)
- ;; CHECK-NEXT:   (if (result f64)
- ;; CHECK-NEXT:    (i32.const 1)
- ;; CHECK-NEXT:    (then
- ;; CHECK-NEXT:     (f64.const 0)
- ;; CHECK-NEXT:    )
- ;; CHECK-NEXT:    (else
- ;; CHECK-NEXT:     (block $block (result f64)
- ;; CHECK-NEXT:      (nop)
- ;; CHECK-NEXT:      (br_if $loop
- ;; CHECK-NEXT:       (i32.eqz
- ;; CHECK-NEXT:        (i32.const 0)
- ;; CHECK-NEXT:       )
+ ;; CHECK-NEXT:   (block $block (result f64)
+ ;; CHECK-NEXT:    (drop
+ ;; CHECK-NEXT:     (block
+ ;; CHECK-NEXT:      (br $block
+ ;; CHECK-NEXT:       (f64.const 0)
  ;; CHECK-NEXT:      )
- ;; CHECK-NEXT:      (unreachable)
  ;; CHECK-NEXT:     )
  ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:    (br_if $loop
+ ;; CHECK-NEXT:     (i32.eqz
+ ;; CHECK-NEXT:      (i32.const 0)
+ ;; CHECK-NEXT:     )
+ ;; CHECK-NEXT:    )
+ ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )

From 904b4ef7c5f163f76890bc34b7c57db14a38973a Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Thu, 12 Jun 2025 11:07:54 +0800
Subject: [PATCH 15/27] Update also

---
 test/passes/remove-unused-brs_enable-multivalue.txt | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/test/passes/remove-unused-brs_enable-multivalue.txt b/test/passes/remove-unused-brs_enable-multivalue.txt
index 8e7881785c1..0f1fa887d66 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.txt
+++ b/test/passes/remove-unused-brs_enable-multivalue.txt
@@ -166,9 +166,10 @@
        (i32.const 12)
       )
       (drop
-       (br_if $topmost
-        (i32.const 1)
-        (i32.const 1)
+       (block
+        (br $topmost
+         (i32.const 1)
+        )
        )
       )
      )
@@ -1088,6 +1089,7 @@
          (drop
           (i32.const 1764950569)
          )
+         (unreachable)
         )
         (f32.const 1.1910939690100655e-32)
         (i32.const 1628057906)

From 9eca5a3f701c626b5fb475baad9ab143042a12fb Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Fri, 13 Jun 2025 20:14:40 +0800
Subject: [PATCH 16/27] Remove unused include

---
 src/passes/RemoveUnusedBrs.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index 54a151a557d..5e561bd1c57 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -27,7 +27,6 @@
 #include "ir/localize.h"
 #include "ir/properties.h"
 #include "ir/utils.h"
-#include "literal.h"
 #include "parsing.h"
 #include "pass.h"
 #include "support/small_set.h"

From 025285111b6071e8a20019511026187134c90c52 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Fri, 13 Jun 2025 20:15:48 +0800
Subject: [PATCH 17/27] NFC: format the comments

---
 src/passes/RemoveUnusedBrs.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index 5e561bd1c57..6bb49471918 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -1890,7 +1890,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
         }
         auto* value = Properties::getFallthrough(
           curr->condition, passOptions, *getModule());
-        // optimize if condition's fallthrough is a constant
+        // Optimize if condition's fallthrough is a constant.
         if (auto* c = value->dynCast<Const>()) {
           ChildLocalizer localizer(
             curr, getFunction(), *getModule(), passOptions);
@@ -1901,7 +1901,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
             curr->type = Type::unreachable;
             block->list.push_back(curr);
             block->finalize();
-            // the type is changed , so refinalize
+            // The type changed, so refinalize.
             refinalize = true;
             replaceCurrent(block);
           } else {

From 71c20822516c2147e15d5f31f4a88f770e8e8f81 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Fri, 13 Jun 2025 20:17:43 +0800
Subject: [PATCH 18/27] Only one replaceCurrent

---
 src/passes/RemoveUnusedBrs.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index 6bb49471918..64c68f2354e 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -1903,15 +1903,14 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
             block->finalize();
             // The type changed, so refinalize.
             refinalize = true;
-            replaceCurrent(block);
           } else {
+            // the branch is never taken, allow control flow to fall through
             if (curr->value) {
               block->list.push_back(curr->value);
               block->finalize();
             }
-            // the branch is never taken, allow control flow to fall through
-            replaceCurrent(block);
           }
+          replaceCurrent(block);
         }
       }
     };

From e6116dc173ac8d0a5e0804b5573fd1f8c4cad12b Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Sun, 15 Jun 2025 09:44:31 +0800
Subject: [PATCH 19/27] Remove unused case

---
 test/lit/passes/O1.wast | 49 -----------------------------------------
 1 file changed, 49 deletions(-)

diff --git a/test/lit/passes/O1.wast b/test/lit/passes/O1.wast
index 099942b2cbf..49271699d73 100644
--- a/test/lit/passes/O1.wast
+++ b/test/lit/passes/O1.wast
@@ -4,19 +4,13 @@
 ;; RUN: foreach %s %t wasm-opt -O1 -S -o - | filecheck %s
 
 (module
-
- (import "env" "fimport$0" (func $fimport$0 (param i32)))
  ;; CHECK:      (type $0 (func (result i32)))
 
- ;; CHECK:      (type $1 (func))
-
  ;; CHECK:      (memory $0 1 1)
  (memory $0 1 1)
  (global $global$0 (mut i32) (i32.const 10))
  ;; CHECK:      (export "foo" (func $foo))
 
- ;; CHECK:      (export "two-branches-unreachable" (func $two-branches-unreachable))
-
  ;; CHECK:      (func $foo (result i32)
  ;; CHECK-NEXT:  (drop
  ;; CHECK-NEXT:   (i32.const 0)
@@ -44,48 +38,5 @@
    (i32.const -2147483648)
   )
  )
- ;; CHECK:      (func $two-branches-unreachable
- ;; CHECK-NEXT:  (local $0 i32)
- ;; CHECK-NEXT:  (if
- ;; CHECK-NEXT:   (i32.eqz
- ;; CHECK-NEXT:    (local.get $0)
- ;; CHECK-NEXT:   )
- ;; CHECK-NEXT:   (then
- ;; CHECK-NEXT:    (unreachable)
- ;; CHECK-NEXT:   )
- ;; CHECK-NEXT:  )
- ;; CHECK-NEXT: )
- (func $two-branches-unreachable (export "two-branches-unreachable")
-  ;; remove-unused-brs makes the break unconditional,
-  ;; thus in this case the two branches are unreachable,
-  ;; refinalization is required.
-  (local $0 i32)
-  (block $label
-   (block $block
-    (if
-     (local.get $0)
-     (then
-      (if
-       (local.tee $0
-        (i32.const 1)
-       )
-       (then
-        (br $label)
-       )
-       (else
-        (br $block)
-       )
-      )
-     )
-     (else
-      (unreachable)
-     )
-    )
-   )
-   (call $fimport$0
-    (local.get $0)
-   )
-  )
- )
 )
 

From 8e92604b6c78608cc06358ac7c0a77b2cfce1137 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xry@stu.ecnu.edu.cn>
Date: Sun, 15 Jun 2025 10:13:46 +0800
Subject: [PATCH 20/27] fine tune to make the irrelevant test case change
 minimal

---
 test/lit/passes/remove-unused-brs.wast        | 42 +++++++------------
 .../remove-unused-brs_all-features.wast       | 28 +++++++------
 2 files changed, 32 insertions(+), 38 deletions(-)

diff --git a/test/lit/passes/remove-unused-brs.wast b/test/lit/passes/remove-unused-brs.wast
index e73b3bfae42..c8e7e91a3cb 100644
--- a/test/lit/passes/remove-unused-brs.wast
+++ b/test/lit/passes/remove-unused-brs.wast
@@ -371,6 +371,7 @@
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT: )
   (func $restructure-br_if-constant-branch-1 (param $x i32)
+    ;;  We can see a nonzero constant falls through the tee, so this br always happens.
     (drop
       (block $x (result i32)
         (drop
@@ -384,6 +385,7 @@
         (i32.const 20)
       )
     )
+    ;; We can see the zero condition, so just let the control flow fall through.
     (drop
       (block $x (result i32)
         (drop
@@ -568,22 +570,13 @@
 
   ;; CHECK:      (func $restructure-br_if-condition-invalidates-6 (type $2) (result i32)
   ;; CHECK-NEXT:  (local $temp i32)
-  ;; CHECK-NEXT:  (local $1 i32)
-  ;; CHECK-NEXT:  (local $2 i32)
   ;; CHECK-NEXT:  (block $block (result i32)
   ;; CHECK-NEXT:   (drop
-  ;; CHECK-NEXT:    (block
-  ;; CHECK-NEXT:     (local.set $1
+  ;; CHECK-NEXT:    (br_if $block
+  ;; CHECK-NEXT:     (local.get $temp)
+  ;; CHECK-NEXT:     (local.tee $temp
   ;; CHECK-NEXT:      (local.get $temp)
   ;; CHECK-NEXT:     )
-  ;; CHECK-NEXT:     (local.set $2
-  ;; CHECK-NEXT:      (local.tee $temp
-  ;; CHECK-NEXT:       (i32.const 1)
-  ;; CHECK-NEXT:      )
-  ;; CHECK-NEXT:     )
-  ;; CHECK-NEXT:     (br $block
-  ;; CHECK-NEXT:      (local.get $1)
-  ;; CHECK-NEXT:     )
   ;; CHECK-NEXT:    )
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:   (local.get $temp)
@@ -598,7 +591,7 @@
         (br_if $block
           (local.get $temp)
           (local.tee $temp
-            (i32.const 1)
+            (local.get $temp)
           )
         )
       )
@@ -607,22 +600,18 @@
   )
 
   ;; CHECK:      (func $restructure-select-no-multivalue (type $1)
-  ;; CHECK-NEXT:  (local $0 (tuple i32 i32))
+  ;; CHECK-NEXT:  (local $x i32)
   ;; CHECK-NEXT:  (tuple.drop 2
   ;; CHECK-NEXT:   (block $block (type $4) (result i32 i32)
-  ;; CHECK-NEXT:    (drop
-  ;; CHECK-NEXT:     (block
-  ;; CHECK-NEXT:      (local.set $0
-  ;; CHECK-NEXT:       (tuple.make 2
-  ;; CHECK-NEXT:        (i32.const 1)
-  ;; CHECK-NEXT:        (call $restructure-br_if
-  ;; CHECK-NEXT:         (i32.const 2)
-  ;; CHECK-NEXT:        )
+  ;; CHECK-NEXT:    (tuple.drop 2
+  ;; CHECK-NEXT:     (br_if $block
+  ;; CHECK-NEXT:      (tuple.make 2
+  ;; CHECK-NEXT:       (i32.const 1)
+  ;; CHECK-NEXT:       (call $restructure-br_if
+  ;; CHECK-NEXT:        (i32.const 2)
   ;; CHECK-NEXT:       )
   ;; CHECK-NEXT:      )
-  ;; CHECK-NEXT:      (br $block
-  ;; CHECK-NEXT:       (local.get $0)
-  ;; CHECK-NEXT:      )
+  ;; CHECK-NEXT:      (local.get $x)
   ;; CHECK-NEXT:     )
   ;; CHECK-NEXT:    )
   ;; CHECK-NEXT:    (tuple.make 2
@@ -633,6 +622,7 @@
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT: )
   (func $restructure-select-no-multivalue
+    (local $x i32)
     (tuple.drop 2
       (block $block (result i32 i32)
         (tuple.drop 2
@@ -647,7 +637,7 @@
                 (i32.const 2)
               )
             )
-            (i32.const 3)
+            (local.get $x)
           )
         )
         (tuple.make 2
diff --git a/test/lit/passes/remove-unused-brs_all-features.wast b/test/lit/passes/remove-unused-brs_all-features.wast
index 3f971df30e1..87c1b2ae197 100644
--- a/test/lit/passes/remove-unused-brs_all-features.wast
+++ b/test/lit/passes/remove-unused-brs_all-features.wast
@@ -64,31 +64,35 @@
  )
 
  ;; CHECK:      (func $test-prefinalize (type $4) (result f64)
+ ;; CHECK-NEXT:  (local $x i32)
  ;; CHECK-NEXT:  (loop $loop (result f64)
- ;; CHECK-NEXT:   (block $block (result f64)
- ;; CHECK-NEXT:    (drop
- ;; CHECK-NEXT:     (block
- ;; CHECK-NEXT:      (br $block
- ;; CHECK-NEXT:       (f64.const 0)
- ;; CHECK-NEXT:      )
- ;; CHECK-NEXT:     )
+ ;; CHECK-NEXT:   (if (result f64)
+ ;; CHECK-NEXT:    (local.get $x)
+ ;; CHECK-NEXT:    (then
+ ;; CHECK-NEXT:     (f64.const 0)
  ;; CHECK-NEXT:    )
- ;; CHECK-NEXT:    (br_if $loop
- ;; CHECK-NEXT:     (i32.eqz
- ;; CHECK-NEXT:      (i32.const 0)
+ ;; CHECK-NEXT:    (else
+ ;; CHECK-NEXT:     (block $block (result f64)
+ ;; CHECK-NEXT:      (nop)
+ ;; CHECK-NEXT:      (br_if $loop
+ ;; CHECK-NEXT:       (i32.eqz
+ ;; CHECK-NEXT:        (i32.const 0)
+ ;; CHECK-NEXT:       )
+ ;; CHECK-NEXT:      )
+ ;; CHECK-NEXT:      (unreachable)
  ;; CHECK-NEXT:     )
  ;; CHECK-NEXT:    )
- ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $test-prefinalize (result f64)
+  (local $x i32)
   (loop $loop (result f64)
    (block $block (result f64)
     (drop
      (br_if $block
       (f64.const 0)
-      (i32.const 1)
+      (local.get $x)
      )
     )
     (if

From 572e9eea5d08c5135e4c7de33c488f9ecf03d52b Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xury5520@outlook.com>
Date: Tue, 17 Jun 2025 13:37:43 +0800
Subject: [PATCH 21/27] Update the comments

---
 test/lit/passes/remove-unused-brs.wast | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/test/lit/passes/remove-unused-brs.wast b/test/lit/passes/remove-unused-brs.wast
index c8e7e91a3cb..da8c61cc941 100644
--- a/test/lit/passes/remove-unused-brs.wast
+++ b/test/lit/passes/remove-unused-brs.wast
@@ -422,10 +422,9 @@
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT: )
   (func $restructure-br_if-constant-branch-2 (param $x i32)
-    ;; there is no value, thus it can be simpler as below
+    ;; as before, but now there is no value.
     (block $x
       (br_if $x
-        ;; the branch is always taken, make it unconditional
         (local.tee $x
           (i32.const 1)
         )
@@ -433,7 +432,6 @@
     )
     (block $x
       (br_if $x
-        ;; the branch is never taken, allow control flow to fall through
         (local.tee $x
           (i32.const 0)
         )

From 832126d502864af8c719fc0dab44672cfb239d0d Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xury5520@outlook.com>
Date: Tue, 17 Jun 2025 14:33:28 +0800
Subject: [PATCH 22/27] Revert remove-unused-brs_shrink-level=1.wast (and
 .txt), use params

---
 .../remove-unused-brs_shrink-level=1.txt      | 70 ++++++++++---------
 .../remove-unused-brs_shrink-level=1.wast     | 30 ++++----
 2 files changed, 53 insertions(+), 47 deletions(-)

diff --git a/test/passes/remove-unused-brs_shrink-level=1.txt b/test/passes/remove-unused-brs_shrink-level=1.txt
index c3d7fc4e6c5..ca446f864bc 100644
--- a/test/passes/remove-unused-brs_shrink-level=1.txt
+++ b/test/passes/remove-unused-brs_shrink-level=1.txt
@@ -53,74 +53,80 @@
   (i32.const 0)
  )
  (func $join-br_ifs
+  (local $x i32)
   (block $out
-   (block
-    (br $out)
-   )
-   (block
-    (br $out)
+   (br_if $out
+    (i32.or
+     (local.get $x)
+     (local.get $x)
+    )
    )
-   (block
-    (br $out)
+   (nop)
+   (br_if $out
+    (local.get $x)
    )
   )
   (block $out2
    (block $out3
-    (block
-     (br $out2)
+    (br_if $out2
+     (local.get $x)
     )
-    (block
-     (br $out3)
+    (br_if $out3
+     (local.get $x)
     )
-    (block
-     (br $out2)
+    (br_if $out2
+     (local.get $x)
     )
    )
    (unreachable)
   )
   (block $out4
    (block $out5
-    (block
-     (br $out4)
-    )
-    (block
-     (br $out5)
+    (br_if $out4
+     (local.get $x)
     )
-    (block
-     (br $out5)
+    (br_if $out5
+     (i32.or
+      (local.get $x)
+      (local.get $x)
+     )
     )
+    (nop)
    )
    (unreachable)
   )
   (block $out6
    (block $out7
-    (block
-     (br $out6)
-    )
-    (block
-     (br $out6)
+    (br_if $out6
+     (i32.or
+      (local.get $x)
+      (local.get $x)
+     )
     )
-    (block
-     (br $out7)
+    (nop)
+    (br_if $out7
+     (local.get $x)
     )
    )
    (unreachable)
   )
   (if
    (i32.eqz
-    (call $b14)
+    (i32.or
+     (call $b14)
+     (local.get $x)
+    )
    )
    (then
     (block $out8
      (nop)
-     (block
-     )
+     (nop)
     )
    )
   )
   (block $out80
-   (block
-    (br $out80)
+   (br_if $out80
+    (local.get $x)
    )
    (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 ce141c43003..4f56f0eed1f 100644
--- a/test/passes/remove-unused-brs_shrink-level=1.wast
+++ b/test/passes/remove-unused-brs_shrink-level=1.wast
@@ -55,41 +55,42 @@
     (i32.const 0)
   )
   (func $join-br_ifs
+    (local $x i32)
     (block $out
-      (br_if $out (i32.const 1))
-      (br_if $out (i32.const 2))
-      (br_if $out (i32.const 3))
+      (br_if $out (local.get $x))
+      (br_if $out (local.get $x))
+      (br_if $out (local.get $x))
     )
     (block $out2
       (block $out3
-        (br_if $out2 (i32.const 1))
-        (br_if $out3 (i32.const 2))
-        (br_if $out2 (i32.const 3))
+        (br_if $out2 (local.get $x))
+        (br_if $out3 (local.get $x))
+        (br_if $out2 (local.get $x))
       )
       (unreachable)
     )
     (block $out4
       (block $out5
-        (br_if $out4 (i32.const 1))
-        (br_if $out5 (i32.const 2))
-        (br_if $out5 (i32.const 3))
+        (br_if $out4 (local.get $x))
+        (br_if $out5 (local.get $x))
+        (br_if $out5 (local.get $x))
       )
       (unreachable)
     )
     (block $out6
       (block $out7
-        (br_if $out6 (i32.const 1))
-        (br_if $out6 (i32.const 2))
-        (br_if $out7 (i32.const 3))
+        (br_if $out6 (local.get $x))
+        (br_if $out6 (local.get $x))
+        (br_if $out7 (local.get $x))
       )
       (unreachable)
     )
     (block $out8
       (br_if $out8 (call $b14)) ;; side effect
-      (br_if $out8 (i32.const 0))
+      (br_if $out8 (local.get $x))
     )
     (block $out8
-      (br_if $out8 (i32.const 1))
+      (br_if $out8 (local.get $x))
       (br_if $out8 (call $b14)) ;; side effect
     )
   )
@@ -190,4 +191,3 @@
     (return (i32.const 3))
   )
 )
-

From fccf9fbe2ce4115748c5b60d8f42e904c6984607 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xury5520@outlook.com>
Date: Tue, 17 Jun 2025 14:38:56 +0800
Subject: [PATCH 23/27] Revert
 remove-unused-brs_shrink-level=1__ignore-implicit-traps.wast (and .txt), use
 params

---
 ...s_shrink-level=1_ignore-implicit-traps.txt | 70 ++++++++++---------
 ..._shrink-level=1_ignore-implicit-traps.wast | 29 ++++----
 2 files changed, 53 insertions(+), 46 deletions(-)

diff --git a/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.txt b/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.txt
index 01c913eacab..461f5bc194b 100644
--- a/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.txt
+++ b/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.txt
@@ -45,74 +45,80 @@
   (i32.const 0)
  )
  (func $join-br_ifs
+  (local $x i32)
   (block $out
-   (block
-    (br $out)
-   )
-   (block
-    (br $out)
+   (br_if $out
+    (i32.or
+     (local.get $x)
+     (local.get $x)
+    )
    )
-   (block
-    (br $out)
+   (nop)
+   (br_if $out
+    (local.get $x)
    )
   )
   (block $out2
    (block $out3
-    (block
-     (br $out2)
+    (br_if $out2
+     (local.get $x)
     )
-    (block
-     (br $out3)
+    (br_if $out3
+     (local.get $x)
     )
-    (block
-     (br $out2)
+    (br_if $out2
+     (local.get $x)
     )
    )
    (unreachable)
   )
   (block $out4
    (block $out5
-    (block
-     (br $out4)
-    )
-    (block
-     (br $out5)
+    (br_if $out4
+     (local.get $x)
     )
-    (block
-     (br $out5)
+    (br_if $out5
+     (i32.or
+      (local.get $x)
+      (local.get $x)
+     )
     )
+    (nop)
    )
    (unreachable)
   )
   (block $out6
    (block $out7
-    (block
-     (br $out6)
-    )
-    (block
-     (br $out6)
+    (br_if $out6
+     (i32.or
+      (local.get $x)
+      (local.get $x)
+     )
     )
-    (block
-     (br $out7)
+    (nop)
+    (br_if $out7
+     (local.get $x)
     )
    )
    (unreachable)
   )
   (if
    (i32.eqz
-    (call $b14)
+    (i32.or
+     (call $b14)
+     (local.get $x)
+    )
    )
    (then
     (block $out8
      (nop)
-     (block
-     )
+     (nop)
     )
    )
   )
   (block $out80
-   (block
-    (br $out80)
+   (br_if $out80
+    (local.get $x)
    )
    (br_if $out80
     (call $b14)
diff --git a/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.wast b/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.wast
index 4f15dc9c020..b93cd89925e 100644
--- a/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.wast
+++ b/test/passes/remove-unused-brs_shrink-level=1_ignore-implicit-traps.wast
@@ -55,41 +55,42 @@
     (i32.const 0)
   )
   (func $join-br_ifs
+    (local $x i32)
     (block $out
-      (br_if $out (i32.const 1))
-      (br_if $out (i32.const 2))
-      (br_if $out (i32.const 3))
+      (br_if $out (local.get $x))
+      (br_if $out (local.get $x))
+      (br_if $out (local.get $x))
     )
     (block $out2
       (block $out3
-        (br_if $out2 (i32.const 1))
-        (br_if $out3 (i32.const 2))
-        (br_if $out2 (i32.const 3))
+        (br_if $out2 (local.get $x))
+        (br_if $out3 (local.get $x))
+        (br_if $out2 (local.get $x))
       )
       (unreachable)
     )
     (block $out4
       (block $out5
-        (br_if $out4 (i32.const 1))
-        (br_if $out5 (i32.const 2))
-        (br_if $out5 (i32.const 3))
+        (br_if $out4 (local.get $x))
+        (br_if $out5 (local.get $x))
+        (br_if $out5 (local.get $x))
       )
       (unreachable)
     )
     (block $out6
       (block $out7
-        (br_if $out6 (i32.const 1))
-        (br_if $out6 (i32.const 2))
-        (br_if $out7 (i32.const 3))
+        (br_if $out6 (local.get $x))
+        (br_if $out6 (local.get $x))
+        (br_if $out7 (local.get $x))
       )
       (unreachable)
     )
     (block $out8
       (br_if $out8 (call $b14)) ;; side effect
-      (br_if $out8 (i32.const 0))
+      (br_if $out8 (local.get $x))
     )
     (block $out8
-      (br_if $out8 (i32.const 1))
+      (br_if $out8 (local.get $x))
       (br_if $out8 (call $b14)) ;; side effect
     )
   )

From 3d1f166a27eeb6c7ad19bc24b9b2e7e6b61655bc Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xury5520@outlook.com>
Date: Tue, 17 Jun 2025 16:35:30 +0800
Subject: [PATCH 24/27] Update also

---
 .../remove-unused-brs_enable-multivalue.txt   | 37 ++++++++++---------
 .../remove-unused-brs_enable-multivalue.wast  | 20 +++++-----
 2 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/test/passes/remove-unused-brs_enable-multivalue.txt b/test/passes/remove-unused-brs_enable-multivalue.txt
index 0f1fa887d66..1b5d9802ce6 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.txt
+++ b/test/passes/remove-unused-brs_enable-multivalue.txt
@@ -62,8 +62,8 @@
  )
  (func $b6 (param $i1 i32)
   (block $topmost
-   (block
-    (br $topmost)
+   (br_if $topmost
+    (local.get $i1)
    )
   )
  )
@@ -73,8 +73,8 @@
     (drop
      (i32.const 0)
     )
-    (block
-     (br $topmost)
+    (br_if $topmost
+     (local.get $i1)
     )
    )
   )
@@ -82,8 +82,8 @@
  (func $b8 (param $i1 i32)
   (block $topmost
    (block $inner
-    (block
-     (br $topmost)
+    (br_if $topmost
+     (local.get $i1)
     )
    )
   )
@@ -91,8 +91,8 @@
  (func $b9 (param $i1 i32)
   (block $topmost
    (block $inner
-    (block
-     (br $topmost)
+    (br_if $topmost
+     (local.get $i1)
     )
    )
   )
@@ -104,8 +104,8 @@
      (drop
       (i32.const 0)
      )
-     (block
-      (br $topmost)
+     (br_if $topmost
+      (local.get $i1)
      )
     )
    )
@@ -118,8 +118,8 @@
      (drop
       (i32.const 0)
      )
-     (block
-      (br $topmost)
+     (br_if $topmost
+      (local.get $i1)
      )
     )
    )
@@ -157,6 +157,7 @@
   )
  )
  (func $b13 (result i32)
+  (local $x i32)
   (block $topmost (result i32)
    (if
     (i32.const 1)
@@ -166,10 +167,9 @@
        (i32.const 12)
       )
       (drop
-       (block
-        (br $topmost
-         (i32.const 1)
-        )
+       (br_if $topmost
+        (local.get $x)
+        (local.get $x)
        )
       )
      )
@@ -225,9 +225,10 @@
   )
  )
  (func $b15
+  (local $x i32)
   (block $topmost
-   (block
-    (br $topmost)
+   (br_if $topmost
+    (local.get $x)
    )
   )
  )
diff --git a/test/passes/remove-unused-brs_enable-multivalue.wast b/test/passes/remove-unused-brs_enable-multivalue.wast
index 0deff0db881..eee8cd3c1ef 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.wast
+++ b/test/passes/remove-unused-brs_enable-multivalue.wast
@@ -59,7 +59,7 @@
   (func $b6 (type $0) (param $i1 i32)
     (block $topmost
       (br_if $topmost
-        (i32.const 1)
+        (local.get $i1)
       )
     )
   )
@@ -70,7 +70,7 @@
           (i32.const 0)
         )
         (br_if $topmost
-          (i32.const 1)
+          (local.get $i1)
         )
       )
     )
@@ -79,7 +79,7 @@
     (block $topmost
       (block $inner
         (br_if $topmost
-          (i32.const 1)
+          (local.get $i1)
         )
       )
     )
@@ -88,7 +88,7 @@
     (block $topmost
       (block $inner
         (br_if $topmost
-          (i32.const 1)
+          (local.get $i1)
         )
       )
     )
@@ -101,7 +101,7 @@
             (i32.const 0)
           )
           (br_if $topmost
-            (i32.const 1)
+            (local.get $i1)
           )
         )
       )
@@ -115,7 +115,7 @@
             (i32.const 0)
           )
           (br_if $inner
-            (i32.const 1)
+            (local.get $i1)
           )
         )
       )
@@ -155,6 +155,7 @@
     )
   )
   (func $b13 (type $2) (result i32)
+    (local $x i32)
     (block $topmost (result i32)
       (if
         (i32.const 1)
@@ -165,8 +166,8 @@
             )
             (drop
               (br_if $topmost
-                (i32.const 1)
-                (i32.const 1)
+                (local.get $x)
+                (local.get $x)
               )
             )
           )
@@ -226,9 +227,10 @@
     )
   )
   (func $b15 (type $1)
+    (local $x i32)
     (block $topmost
       (if
-        (i32.const 17)
+        (local.get $x)
         (then
           (br $topmost)
         )

From 1dcd61b13829d993989cc5eb3ce679e61ebb282e Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xury5520@outlook.com>
Date: Wed, 18 Jun 2025 14:32:59 +0800
Subject: [PATCH 25/27] Update tests, keep minimal change

---
 .../remove-unused-brs_enable-multivalue.txt   | 124 +++++++++++-------
 .../remove-unused-brs_enable-multivalue.wast  |  54 ++++----
 2 files changed, 103 insertions(+), 75 deletions(-)

diff --git a/test/passes/remove-unused-brs_enable-multivalue.txt b/test/passes/remove-unused-brs_enable-multivalue.txt
index 1b5d9802ce6..789e582e6d3 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.txt
+++ b/test/passes/remove-unused-brs_enable-multivalue.txt
@@ -504,6 +504,7 @@
   )
  )
  (func $loops
+  (local $x i32)
   (loop $in
    (block $out
     (br_if $in
@@ -518,13 +519,15 @@
   )
   (loop
    (block $out0
-    (block
+    (br_if $out0
+     (local.get $x)
     )
    )
   )
   (loop $in1
    (block $out1
-    (block
+    (br_if $out1
+     (local.get $x)
     )
    )
   )
@@ -535,17 +538,24 @@
    )
   )
   (loop $in4
-   (block $out3
-    (block
+   (if
+    (i32.eqz
+     (local.get $x)
     )
-    (block
-     (br $in4)
+    (then
+     (block $out3
+      (nop)
+      (br_if $in4
+       (local.get $x)
+      )
+     )
     )
    )
   )
   (loop $in5
    (block $out4
-    (block
+    (br_if $in5
+     (local.get $x)
     )
    )
   )
@@ -756,17 +766,19 @@
   )
   (loop $in19
    (block $out18
-    (block
+    (drop
+     (local.get $x)
     )
     (br $in19)
    )
   )
   (loop $in-not
    (block $out-not
-    (block
-     (br $out-not)
+    (br_if $out-not
+     (local.get $x)
     )
-    (block
+    (br_if $out-not
+     (local.get $x)
     )
     (call $loops)
     (br $in-not)
@@ -824,16 +836,17 @@
   )
  )
  (func $threading
+  (local $x i32)
   (drop
    (block $value-out (result i32)
     (block $value-in (result i32)
      (block $out
       (block $in
-       (block
-        (br $out)
+       (br_if $out
+        (local.get $x)
        )
-       (block
-        (br $out)
+       (br_if $out
+        (local.get $x)
        )
        (br $value-in
         (i32.const 3)
@@ -848,8 +861,8 @@
    (block $stack2
     (block $stack3
      (block $stack4
-      (block
-       (br $stack1)
+      (br_if $stack1
+       (local.get $x)
       )
       (unreachable)
      )
@@ -874,7 +887,9 @@
        )
       )
       (else
-       (br $leave)
+       (br_if $leave
+        (local.get $x)
+       )
       )
      )
      (unreachable)
@@ -893,7 +908,9 @@
      (if
       (local.get $x)
       (then
-       (br $leave)
+       (br_if $leave
+        (local.get $x)
+       )
       )
       (else
        (br $out
@@ -980,18 +997,26 @@
   )
  )
  (func $iffify
-  (block $yes
-   (block
-   )
-   (drop
-    (i32.const 1)
+  (local $x i32)
+  (if
+   (i32.eqz
+    (local.get $x)
    )
-   (drop
-    (i32.const 2)
+   (then
+    (block $yes
+     (nop)
+     (drop
+      (i32.const 1)
+     )
+     (drop
+      (i32.const 2)
+     )
+    )
    )
   )
   (block $no
-   (block
+   (br_if $no
+    (local.get $x)
    )
    (drop
     (i32.const 1)
@@ -1002,7 +1027,8 @@
    )
   )
   (block $no2
-   (block
+   (br_if $no2
+    (local.get $x)
    )
   )
   (block $no3
@@ -1016,7 +1042,8 @@
   )
   (block $no5
    (block $no4
-    (block
+    (br_if $no5
+     (local.get $x)
     )
     (drop
      (i32.const 1)
@@ -1072,25 +1099,22 @@
  (func $untaken-brs-might-prevent-block-removal (param $0 f32) (param $1 i32) (param $2 f32) (param $3 i32) (param $4 i32) (param $5 f64) (param $6 f32) (result i32)
   (block $label$0 (result i32)
    (block $label$1
-    (block
-     (br $label$1)
+    (br_if $label$1
+     (local.get $1)
     )
     (br_if $label$1
      (i32.load offset=3 align=1
       (select
        (call $untaken-brs-might-prevent-block-removal
         (f32.const 1.4904844647389837e-07)
-        (block
+        (br_if $label$0
          (i32.store16 offset=4 align=1
           (i32.const 1900641)
           (br $label$0
            (i32.const 1628075109)
           )
          )
-         (drop
-          (i32.const 1764950569)
-         )
-         (unreachable)
+         (local.get $1)
         )
         (f32.const 1.1910939690100655e-32)
         (i32.const 1628057906)
@@ -1905,8 +1929,10 @@
   )
  )
  (func $same-target-br_if-and-br
+  (local $x i32)
   (block $x
-   (block
+   (drop
+    (local.get $x)
    )
    (br $x)
    (unreachable)
@@ -2292,9 +2318,10 @@
   )
  )
  (func $if-block-br
+  (local $x i32)
   (block $label
-   (block
-    (br $label)
+   (br_if $label
+    (local.get $x)
    )
   )
  )
@@ -2511,6 +2538,7 @@
   )
  )
  (func $refinalize-need-br-value (result i32)
+  (local $x i32)
   (loop $label$3 (result i32)
    (block $label$6 (result i32)
     (block $label$10
@@ -2518,7 +2546,8 @@
      (block $label$503
       (br_if $label$3
        (block $label$530 (result i32)
-        (block
+        (br_if $label$503
+         (local.get $x)
         )
         (i32.const 0)
        )
@@ -2840,7 +2869,6 @@
  )
  (func $if_br_if
   (local $0 i32)
-  (local $1 i32)
   (block $label$1
    (br_if $label$1
     (select
@@ -2873,15 +2901,11 @@
      )
     )
    )
-   (if
-    (i32.const 1026)
-    (then
-     (local.set $1
-      (local.tee $0
-       (i32.const -7)
-      )
-     )
-     (br $label$1)
+   (br_if $label$1
+    (select
+     (i32.const 1026)
+     (i32.const 0)
+     (local.get $0)
     )
    )
    (i32.store
diff --git a/test/passes/remove-unused-brs_enable-multivalue.wast b/test/passes/remove-unused-brs_enable-multivalue.wast
index eee8cd3c1ef..55c276b8cb5 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.wast
+++ b/test/passes/remove-unused-brs_enable-multivalue.wast
@@ -540,6 +540,7 @@
     )
   )
   (func $loops
+    (local $x i32)
     (loop $in
       (block $out
         (if (i32.const 0) (then (br $out)))
@@ -551,13 +552,13 @@
     )
     (loop
       (block $out
-        (if (i32.const 0) (then (br $out)))
+        (if (local.get $x) (then (br $out)))
         (br $out)
       )
     )
     (loop $in
       (block $out
-        (if (i32.const 0) (then (br $out)))
+        (if (local.get $x) (then (br $out)))
         (br $out)
       )
     )
@@ -567,13 +568,13 @@
     )
     (loop $in
       (block $out
-        (if (i32.const 0) (then (br $out)))
-        (br_if $in (i32.const 1))
+        (if (local.get $x) (then (br $out)))
+        (br_if $in (local.get $x))
       )
     )
     (loop $in
       (block $out
-        (if (i32.const 0) (then (br $in)))
+        (if (local.get $x) (then (br $in)))
         (br $out)
       )
     )
@@ -757,14 +758,14 @@
     )
     (loop $in
       (block $out
-        (br_if $in (i32.const 0))
+        (br_if $in (local.get $x))
         (br $in)
       )
     )
     (loop $in-not ;; do NOT if-ify, the block can't be removed
       (block $out-not
-        (br_if $out-not (i32.const -1))
-        (br_if $out-not (i32.const 0))
+        (br_if $out-not (local.get $x))
+        (br_if $out-not (local.get $x))
         (call $loops)
         (br $in-not)
       )
@@ -792,17 +793,18 @@
     )
   )
   (func $threading
+    (local $x i32)
     (drop
       (block $value-out (result i32)
         (block $value-in (result i32)
           (block $out
             (block $in
-              (if (i32.const 1)
+              (if (local.get $x)
                 (then
                   (br $in)
                 )
               )
-              (br_if $in (i32.const 2))
+              (br_if $in (local.get $x))
               (br $value-in (i32.const 3))
             )
             (br $out)
@@ -815,7 +817,7 @@
       (block $stack2
         (block $stack3
           (block $stack4
-            (if (i32.const 1)
+            (if (local.get $x)
               (then
                 (br $stack4)
               )
@@ -844,7 +846,7 @@
               )
             )
             (else
-              (br_if $leave (i32.const 1))
+              (br_if $leave (local.get $x))
             )
           )
           (unreachable)
@@ -860,7 +862,7 @@
           (if
             (local.get $x)
             (then
-              (br_if $leave (i32.const 1))
+              (br_if $leave (local.get $x))
             )
             (else
               (br $out
@@ -937,16 +939,17 @@
     )
   )
   (func $iffify
+    (local $x i32)
     (block $yes
       (br_if $yes
-        (i32.const 0)
+        (local.get $x)
       )
       (drop (i32.const 1))
       (drop (i32.const 2))
     )
     (block $no
       (br_if $no
-        (i32.const 0)
+        (local.get $x)
       )
       (drop (i32.const 1))
       (br $no)
@@ -954,7 +957,7 @@
     )
     (block $no2
       (br_if $no2
-        (i32.const 0)
+        (local.get $x)
       )
     )
     (block $no3
@@ -965,7 +968,7 @@
     (block $no5
       (block $no4
         (br_if $no5
-          (i32.const 0)
+          (local.get $x)
         )
         (drop (i32.const 1))
         (drop (i32.const 2))
@@ -1013,7 +1016,7 @@
    (block $label$0 (result i32)
     (block $label$1 ;; this block has no taken brs, but we can't remove it without removing them first
      (br_if $label$1
-      (i32.const 607395945)
+      (local.get $1)
      )
      (br_if $label$1
       (i32.load16_s offset=3 align=1
@@ -1027,7 +1030,7 @@
             (i32.const 1628075109)
            )
           )
-          (i32.const 1764950569)
+          (local.get $1)
          )
          (f32.const 1.1910939690100655e-32)
          (i32.const 1628057906)
@@ -1617,9 +1620,10 @@
     )
   )
   (func $same-target-br_if-and-br
+    (local $x i32)
     (block $x
       (br_if $x
-        (i32.const 0)
+        (local.get $x)
       )
       (br $x)
       (unreachable)
@@ -1945,9 +1949,10 @@
    )
   )
   (func $if-block-br
+   (local $x i32)
    (block $label
     (if
-     (i32.const 1)
+     (local.get $x)
      (then
       (br $label)
      )
@@ -2162,6 +2167,7 @@
    )
   )
   (func $refinalize-need-br-value (result i32)
+   (local $x i32)
    (loop $label$3 (result i32)
     (block $label$6 (result i32)
      (block $label$10
@@ -2170,7 +2176,7 @@
        (br_if $label$3
         (block $label$530 (result i32)
          (br_if $label$503 ;; while this br does not send a value
-          (i32.const 0)
+          (local.get $x)
          )
          (i32.const 0)
         )
@@ -2570,9 +2576,7 @@
     (i32.const 1026)
     (then
      (br_if $label$1
-      (local.tee $0 ;; but here it is *not* ok
-       (i32.const -7)
-      )
+      (local.get $0) ;; but here it is *not* ok
      )
     )
    )

From c036d3f955766dc138e1bf0273db3509a1e47e6d Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xury5520@outlook.com>
Date: Wed, 18 Jun 2025 14:42:28 +0800
Subject: [PATCH 26/27] Amend remove-unused-brs_shrink-level=1.txt

---
 test/passes/remove-unused-brs_shrink-level=1.txt  | 8 ++++++--
 test/passes/remove-unused-brs_shrink-level=1.wast | 6 ++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/test/passes/remove-unused-brs_shrink-level=1.txt b/test/passes/remove-unused-brs_shrink-level=1.txt
index ca446f864bc..127f30508d7 100644
--- a/test/passes/remove-unused-brs_shrink-level=1.txt
+++ b/test/passes/remove-unused-brs_shrink-level=1.txt
@@ -150,17 +150,21 @@
   )
  )
  (func $br-if-unreachable-pair
+  (local $x i32)
   (block $label$14
    (br_if $label$14
     (unreachable)
    )
-   (block
+   (br_if $label$14
+    (local.get $x)
    )
   )
  )
  (func $br-if-unreachable-pair2
+  (local $x i32)
   (block $label$14
-   (block
+   (br_if $label$14
+    (local.get $x)
    )
    (br_if $label$14
     (unreachable)
diff --git a/test/passes/remove-unused-brs_shrink-level=1.wast b/test/passes/remove-unused-brs_shrink-level=1.wast
index 4f56f0eed1f..00d29376b06 100644
--- a/test/passes/remove-unused-brs_shrink-level=1.wast
+++ b/test/passes/remove-unused-brs_shrink-level=1.wast
@@ -111,19 +111,21 @@
    )
   )
   (func $br-if-unreachable-pair
+   (local $x i32)
    (block $label$14
     (br_if $label$14
      (unreachable)
     )
     (br_if $label$14
-     (i32.const 0)
+     (local.get $x)
     )
    )
   )
   (func $br-if-unreachable-pair2
+   (local $x i32)
    (block $label$14
     (br_if $label$14
-     (i32.const 0)
+     (local.get $x)
     )
     (br_if $label$14
      (unreachable)

From 6cd99243a2b80cd89effa77c01e968c702930606 Mon Sep 17 00:00:00 2001
From: Ruiyang Xu <xury5520@outlook.com>
Date: Sat, 21 Jun 2025 04:58:29 +0800
Subject: [PATCH 27/27] Update

---
 test/passes/remove-unused-brs_enable-multivalue.txt | 13 ++++++++-----
 .../passes/remove-unused-brs_enable-multivalue.wast |  4 +++-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/test/passes/remove-unused-brs_enable-multivalue.txt b/test/passes/remove-unused-brs_enable-multivalue.txt
index 789e582e6d3..321b061e524 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.txt
+++ b/test/passes/remove-unused-brs_enable-multivalue.txt
@@ -2901,11 +2901,14 @@
      )
     )
    )
-   (br_if $label$1
-    (select
-     (i32.const 1026)
-     (i32.const 0)
-     (local.get $0)
+   (if
+    (i32.const 1026)
+    (then
+     (br_if $label$1
+      (local.tee $0
+       (local.get $0)
+      )
+     )
     )
    )
    (i32.store
diff --git a/test/passes/remove-unused-brs_enable-multivalue.wast b/test/passes/remove-unused-brs_enable-multivalue.wast
index 55c276b8cb5..acbd3781ab9 100644
--- a/test/passes/remove-unused-brs_enable-multivalue.wast
+++ b/test/passes/remove-unused-brs_enable-multivalue.wast
@@ -2576,7 +2576,9 @@
     (i32.const 1026)
     (then
      (br_if $label$1
-      (local.get $0) ;; but here it is *not* ok
+      (local.tee $0 ;; but here it is *not* ok
+        (local.get $0)
+      )
      )
     )
    )