br_if returns its value

16 files changed, 157 insertions, 105 deletions

diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index fa8ab2f6c..15482de25 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -146,11 +146,10 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs, Visitor<R
       // if without an else. try to reduce   if (condition) br  =>  br_if (condition)
       Break* br = curr->ifTrue->dynCast<Break>();
       if (br && !br->condition) { // TODO: if there is a condition, join them
-        // if the br has a value, then if => br_if means we always execute the value, and also the order is value,condition vs condition,value
         if (canTurnIfIntoBrIf(curr->condition, br->value)) {
           br->condition = curr->condition;
           br->finalize();
-          replaceCurrent(br);
+          replaceCurrent(Builder(*getModule()).dropIfConcretelyTyped(br));
           anotherCycle = true;
         }
       }
@@ -407,18 +406,18 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs, Visitor<R
           auto* ifTrueBreak = iff->ifTrue->dynCast<Break>();
           if (ifTrueBreak && !ifTrueBreak->condition && canTurnIfIntoBrIf(iff->condition, ifTrueBreak->value)) {
             // we are an if-else where the ifTrue is a break without a condition, so we can do this
-            list[i] = ifTrueBreak;
             ifTrueBreak->condition = iff->condition;
             ifTrueBreak->finalize();
+            list[i] = Builder(*getModule()).dropIfConcretelyTyped(ifTrueBreak);
             ExpressionManipulator::spliceIntoBlock(curr, i + 1, iff->ifFalse);
             continue;
           }
           // otherwise, perhaps we can flip the if
           auto* ifFalseBreak = iff->ifFalse->dynCast<Break>();
           if (ifFalseBreak && !ifFalseBreak->condition && canTurnIfIntoBrIf(iff->condition, ifFalseBreak->value)) {
-            list[i] = ifFalseBreak;
             ifFalseBreak->condition = Builder(*getModule()).makeUnary(EqZInt32, iff->condition);
             ifFalseBreak->finalize();
+            list[i] = Builder(*getModule()).dropIfConcretelyTyped(ifFalseBreak);
             ExpressionManipulator::spliceIntoBlock(curr, i + 1, iff->ifTrue);
             continue;
           }
diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index f9b2e73f6..546d72391 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -339,6 +339,12 @@ public:
     input->finalize();
     return ret;
   }
+
+  // Drop an expression if it has a concrete type
+  Expression* dropIfConcretelyTyped(Expression* curr) {
+    if (!isConcreteWasmType(curr->type)) return curr;
+    return makeDrop(curr);
+  }
 };
 
 } // namespace wasm
diff --git a/src/wasm-interpreter.h b/src/wasm-interpreter.h
index 292d6a521..5d4e7d7b4 100644
--- a/src/wasm-interpreter.h
+++ b/src/wasm-interpreter.h
@@ -155,18 +155,19 @@ public:
   Flow visitBreak(Break *curr) {
     NOTE_ENTER("Break");
     bool condition = true;
-    Flow flow(curr->name);
+    Flow flow;
     if (curr->value) {
       flow = visit(curr->value);
       if (flow.breaking()) return flow;
-      flow.breakTo = curr->name;
     }
     if (curr->condition) {
       Flow conditionFlow = visit(curr->condition);
       if (conditionFlow.breaking()) return conditionFlow;
       condition = conditionFlow.value.getInteger() != 0;
+      if (!condition) return flow;
     }
-    return condition ? flow : Flow();
+    flow.breakTo = curr->name;
+    return flow;
   }
   Flow visitSwitch(Switch *curr) {
     NOTE_ENTER("Switch");
diff --git a/src/wasm.h b/src/wasm.h
index 4d5cf4d70..1bce0bac9 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -1027,7 +1027,11 @@ public:
 
   void finalize() {
     if (condition) {
-      type = none;
+      if (value) {
+        type = value->type;
+      } else {
+        type = none;
+      }
     } else {
       type = unreachable;
     }
diff --git a/test/emcc_O2_hello_world.fromasm b/test/emcc_O2_hello_world.fromasm
index b8e25baa5..072d9f97f 100644
--- a/test/emcc_O2_hello_world.fromasm
+++ b/test/emcc_O2_hello_world.fromasm
@@ -4674,11 +4674,13 @@
                                         )
                                       )
                                       (block i32
-                                        (br_if $do-once$67
-                                          (i32.const 31)
-                                          (i32.gt_u
-                                            (get_local $15)
-                                            (i32.const 16777215)
+                                        (drop
+                                          (br_if $do-once$67
+                                            (i32.const 31)
+                                            (i32.gt_u
+                                              (get_local $15)
+                                              (i32.const 16777215)
+                                            )
                                           )
                                         )
                                         (i32.or
diff --git a/test/emcc_O2_hello_world.fromasm.imprecise b/test/emcc_O2_hello_world.fromasm.imprecise
index f2b2c401c..233a485b8 100644
--- a/test/emcc_O2_hello_world.fromasm.imprecise
+++ b/test/emcc_O2_hello_world.fromasm.imprecise
@@ -4672,11 +4672,13 @@
                                         )
                                       )
                                       (block i32
-                                        (br_if $do-once$67
-                                          (i32.const 31)
-                                          (i32.gt_u
-                                            (get_local $15)
-                                            (i32.const 16777215)
+                                        (drop
+                                          (br_if $do-once$67
+                                            (i32.const 31)
+                                            (i32.gt_u
+                                              (get_local $15)
+                                              (i32.const 16777215)
+                                            )
                                           )
                                         )
                                         (i32.or
diff --git a/test/emcc_hello_world.fromasm b/test/emcc_hello_world.fromasm
index 24f6d4f75..a12c7fe56 100644
--- a/test/emcc_hello_world.fromasm
+++ b/test/emcc_hello_world.fromasm
@@ -4607,15 +4607,17 @@
                                                   (i32.const 1)
                                                 )
                                                 (block i32
-                                                  (br_if $do-once$64
-                                                    (get_local $6)
-                                                    (i32.and
-                                                      (get_local $16)
+                                                  (drop
+                                                    (br_if $do-once$64
+                                                      (get_local $6)
                                                       (i32.and
-                                                        (get_local $12)
-                                                        (f64.eq
-                                                          (get_local $14)
-                                                          (f64.const 0)
+                                                        (get_local $16)
+                                                        (i32.and
+                                                          (get_local $12)
+                                                          (f64.eq
+                                                            (get_local $14)
+                                                            (f64.const 0)
+                                                          )
                                                         )
                                                       )
                                                     )
@@ -4965,10 +4967,12 @@
                                                       )
                                                     )
                                                   )
-                                                  (br_if $do-once$70
-                                                    (get_local $9)
-                                                    (i32.eqz
-                                                      (get_local $5)
+                                                  (drop
+                                                    (br_if $do-once$70
+                                                      (get_local $9)
+                                                      (i32.eqz
+                                                        (get_local $5)
+                                                      )
                                                     )
                                                   )
                                                   (i32.store
@@ -5175,10 +5179,12 @@
                                                                 )
                                                               )
                                                             )
-                                                            (br_if $do-once$78
-                                                              (get_local $5)
-                                                              (i32.eqz
-                                                                (get_local $9)
+                                                            (drop
+                                                              (br_if $do-once$78
+                                                                (get_local $5)
+                                                                (i32.eqz
+                                                                  (get_local $9)
+                                                                )
                                                               )
                                                             )
                                                             (i32.store
@@ -5513,13 +5519,15 @@
                                                     (if
                                                       (get_local $30)
                                                       (block f64
-                                                        (br_if $do-once$90
-                                                          (get_local $22)
-                                                          (i32.ne
-                                                            (i32.load8_s
-                                                              (get_local $36)
+                                                        (drop
+                                                          (br_if $do-once$90
+                                                            (get_local $22)
+                                                            (i32.ne
+                                                              (i32.load8_s
+                                                                (get_local $36)
+                                                              )
+                                                              (i32.const 45)
                                                             )
-                                                            (i32.const 45)
                                                           )
                                                         )
                                                         (set_local $14
@@ -12607,11 +12615,13 @@
                                       )
                                     )
                                     (block i32
-                                      (br_if $do-once$69
-                                        (i32.const 31)
-                                        (i32.gt_u
-                                          (get_local $2)
-                                          (i32.const 16777215)
+                                      (drop
+                                        (br_if $do-once$69
+                                          (i32.const 31)
+                                          (i32.gt_u
+                                            (get_local $2)
+                                            (i32.const 16777215)
+                                          )
                                         )
                                       )
                                       (i32.or
diff --git a/test/emcc_hello_world.fromasm.imprecise b/test/emcc_hello_world.fromasm.imprecise
index c6123841a..75534025e 100644
--- a/test/emcc_hello_world.fromasm.imprecise
+++ b/test/emcc_hello_world.fromasm.imprecise
@@ -4600,15 +4600,17 @@
                                                   (i32.const 1)
                                                 )
                                                 (block i32
-                                                  (br_if $do-once$64
-                                                    (get_local $6)
-                                                    (i32.and
-                                                      (get_local $16)
+                                                  (drop
+                                                    (br_if $do-once$64
+                                                      (get_local $6)
                                                       (i32.and
-                                                        (get_local $12)
-                                                        (f64.eq
-                                                          (get_local $14)
-                                                          (f64.const 0)
+                                                        (get_local $16)
+                                                        (i32.and
+                                                          (get_local $12)
+                                                          (f64.eq
+                                                            (get_local $14)
+                                                            (f64.const 0)
+                                                          )
                                                         )
                                                       )
                                                     )
@@ -4958,10 +4960,12 @@
                                                       )
                                                     )
                                                   )
-                                                  (br_if $do-once$70
-                                                    (get_local $9)
-                                                    (i32.eqz
-                                                      (get_local $5)
+                                                  (drop
+                                                    (br_if $do-once$70
+                                                      (get_local $9)
+                                                      (i32.eqz
+                                                        (get_local $5)
+                                                      )
                                                     )
                                                   )
                                                   (i32.store
@@ -5168,10 +5172,12 @@
                                                                 )
                                                               )
                                                             )
-                                                            (br_if $do-once$78
-                                                              (get_local $5)
-                                                              (i32.eqz
-                                                                (get_local $9)
+                                                            (drop
+                                                              (br_if $do-once$78
+                                                                (get_local $5)
+                                                                (i32.eqz
+                                                                  (get_local $9)
+                                                                )
                                                               )
                                                             )
                                                             (i32.store
@@ -5506,13 +5512,15 @@
                                                     (if
                                                       (get_local $30)
                                                       (block f64
-                                                        (br_if $do-once$90
-                                                          (get_local $22)
-                                                          (i32.ne
-                                                            (i32.load8_s
-                                                              (get_local $36)
+                                                        (drop
+                                                          (br_if $do-once$90
+                                                            (get_local $22)
+                                                            (i32.ne
+                                                              (i32.load8_s
+                                                                (get_local $36)
+                                                              )
+                                                              (i32.const 45)
                                                             )
-                                                            (i32.const 45)
                                                           )
                                                         )
                                                         (set_local $14
@@ -12600,11 +12608,13 @@
                                       )
                                     )
                                     (block i32
-                                      (br_if $do-once$69
-                                        (i32.const 31)
-                                        (i32.gt_u
-                                          (get_local $2)
-                                          (i32.const 16777215)
+                                      (drop
+                                        (br_if $do-once$69
+                                          (i32.const 31)
+                                          (i32.gt_u
+                                            (get_local $2)
+                                            (i32.const 16777215)
+                                          )
                                         )
                                       )
                                       (i32.or
diff --git a/test/example/c-api-kitchen-sink.txt b/test/example/c-api-kitchen-sink.txt
index 41d64089e..28d7b759b 100644
--- a/test/example/c-api-kitchen-sink.txt
+++ b/test/example/c-api-kitchen-sink.txt
@@ -422,9 +422,11 @@ BinaryenFloat64: 4
                 (i32.const 0)
               )
             )
-            (br_if $the-value
-              (i32.const 1)
-              (i32.const 0)
+            (drop
+              (br_if $the-value
+                (i32.const 1)
+                (i32.const 0)
+              )
             )
             (br_if $the-nothing
               (i32.const 2)
@@ -2013,9 +2015,11 @@ int main() {
                 (i32.const 0)
               )
             )
-            (br_if $the-value
-              (i32.const 1)
-              (i32.const 0)
+            (drop
+              (br_if $the-value
+                (i32.const 1)
+                (i32.const 0)
+              )
             )
             (br_if $the-nothing
               (i32.const 2)
diff --git a/test/example/c-api-kitchen-sink.txt.txt b/test/example/c-api-kitchen-sink.txt.txt
index 10a698717..f66b714eb 100644
--- a/test/example/c-api-kitchen-sink.txt.txt
+++ b/test/example/c-api-kitchen-sink.txt.txt
@@ -417,9 +417,11 @@
                 (i32.const 0)
               )
             )
-            (br_if $the-value
-              (i32.const 1)
-              (i32.const 0)
+            (drop
+              (br_if $the-value
+                (i32.const 1)
+                (i32.const 0)
+              )
             )
             (br_if $the-nothing
               (i32.const 2)
diff --git a/test/memorygrowth.fromasm b/test/memorygrowth.fromasm
index a07d71fd4..7efde4442 100644
--- a/test/memorygrowth.fromasm
+++ b/test/memorygrowth.fromasm
@@ -4730,11 +4730,13 @@
                                         )
                                       )
                                       (block i32
-                                        (br_if $do-once$67
-                                          (i32.const 31)
-                                          (i32.gt_u
-                                            (get_local $14)
-                                            (i32.const 16777215)
+                                        (drop
+                                          (br_if $do-once$67
+                                            (i32.const 31)
+                                            (i32.gt_u
+                                              (get_local $14)
+                                              (i32.const 16777215)
+                                            )
                                           )
                                         )
                                         (i32.or
diff --git a/test/memorygrowth.fromasm.imprecise b/test/memorygrowth.fromasm.imprecise
index ea085352f..1a93b6e60 100644
--- a/test/memorygrowth.fromasm.imprecise
+++ b/test/memorygrowth.fromasm.imprecise
@@ -4728,11 +4728,13 @@
                                         )
                                       )
                                       (block i32
-                                        (br_if $do-once$67
-                                          (i32.const 31)
-                                          (i32.gt_u
-                                            (get_local $14)
-                                            (i32.const 16777215)
+                                        (drop
+                                          (br_if $do-once$67
+                                            (i32.const 31)
+                                            (i32.gt_u
+                                              (get_local $14)
+                                              (i32.const 16777215)
+                                            )
                                           )
                                         )
                                         (i32.or
diff --git a/test/passes/remove-unused-brs.txt b/test/passes/remove-unused-brs.txt
index 3c51c8f99..da19d7ac8 100644
--- a/test/passes/remove-unused-brs.txt
+++ b/test/passes/remove-unused-brs.txt
@@ -152,9 +152,11 @@
           (drop
             (i32.const 12)
           )
-          (br_if $topmost
-            (i32.const 1)
-            (i32.const 1)
+          (drop
+            (br_if $topmost
+              (i32.const 1)
+              (i32.const 1)
+            )
           )
         )
         (block $block3
diff --git a/test/passes/remove-unused-brs.wast b/test/passes/remove-unused-brs.wast
index 995ab2d3a..50d936dc7 100644
--- a/test/passes/remove-unused-brs.wast
+++ b/test/passes/remove-unused-brs.wast
@@ -158,9 +158,11 @@
           (drop
             (i32.const 12)
           )
-          (br_if $topmost
-            (i32.const 1)
-            (i32.const 1)
+          (drop
+            (br_if $topmost
+              (i32.const 1)
+              (i32.const 1)
+            )
           )
         )
         (block $block3
diff --git a/test/unit.fromasm b/test/unit.fromasm
index ea0ff0843..fe8b616f4 100644
--- a/test/unit.fromasm
+++ b/test/unit.fromasm
@@ -493,10 +493,12 @@
   )
   (func $phi (result i32)
     (block $do-once$0 i32
-      (br_if $do-once$0
-        (i32.const 0)
-        (call $lb
-          (i32.const 1)
+      (drop
+        (br_if $do-once$0
+          (i32.const 0)
+          (call $lb
+            (i32.const 1)
+          )
         )
       )
       (i32.const 1)
diff --git a/test/unit.fromasm.imprecise b/test/unit.fromasm.imprecise
index 5ea81aad3..8752f179a 100644
--- a/test/unit.fromasm.imprecise
+++ b/test/unit.fromasm.imprecise
@@ -474,10 +474,12 @@
   )
   (func $phi (result i32)
     (block $do-once$0 i32
-      (br_if $do-once$0
-        (i32.const 0)
-        (call $lb
-          (i32.const 1)
+      (drop
+        (br_if $do-once$0
+          (i32.const 0)
+          (call $lb
+            (i32.const 1)
+          )
         )
       )
       (i32.const 1)