From 68b57f6c015af1eaf95b039b0bc2bc3b9efbab4e Mon Sep 17 00:00:00 2001
From: Alon Zakai <alonzakai@gmail.com>
Date: Tue, 5 Sep 2017 11:33:22 -0700
Subject: when if arms are identical, merging them may change the type of the
 if, if it has a forced type

---
 test/passes/optimize-instructions.txt  | 34 ++++++++++++++++++++++++++++++++++
 test/passes/optimize-instructions.wast | 21 +++++++++++++++++++++
 2 files changed, 55 insertions(+)

(limited to 'test')

diff --git a/test/passes/optimize-instructions.txt b/test/passes/optimize-instructions.txt
index 6a99ee106..aae0724a0 100644
--- a/test/passes/optimize-instructions.txt
+++ b/test/passes/optimize-instructions.txt
@@ -1913,6 +1913,40 @@
     )
    )
   )
+  (drop
+   (block (result i32)
+    (i32.add
+     (get_local $1)
+     (unreachable)
+    )
+   )
+  )
+  (drop
+   (block (result i32)
+    (drop
+     (tee_local $0
+      (get_local $1)
+     )
+    )
+    (i32.add
+     (get_local $1)
+     (unreachable)
+    )
+   )
+  )
+  (drop
+   (if (result i32)
+    (unreachable)
+    (i32.add
+     (get_local $1)
+     (unreachable)
+    )
+    (i32.add
+     (get_local $1)
+     (unreachable)
+    )
+   )
+  )
  )
  (func $select-parallel (type $4) (param $0 i32) (param $1 i32)
   (drop
diff --git a/test/passes/optimize-instructions.wast b/test/passes/optimize-instructions.wast
index c26aad196..f84be8330 100644
--- a/test/passes/optimize-instructions.wast
+++ b/test/passes/optimize-instructions.wast
@@ -2321,6 +2321,27 @@
         (i32.add (get_local $1) (i32.const 1))
       )
     )
+    (drop
+      (if (result i32)
+        (get_local $0)
+        (i32.add (get_local $1) (unreachable)) ;; folding them would change the type of the if
+        (i32.add (get_local $1) (unreachable))
+      )
+    )
+    (drop
+      (if (result i32)
+        (tee_local $0 (get_local $1)) ;; side effects!
+        (i32.add (get_local $1) (unreachable)) ;; folding them would change the type of the if
+        (i32.add (get_local $1) (unreachable))
+      )
+    )
+    (drop
+      (if (result i32)
+        (unreachable) ;; !!!
+        (i32.add (get_local $1) (unreachable)) ;; folding them would change the type of the if
+        (i32.add (get_local $1) (unreachable))
+      )
+    )
   )
   (func $select-parallel (param $0 i32) (param $1 i32)
     (drop
-- 
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