optimize out eqz^2

2 files changed, 30 insertions, 0 deletions

diff --git a/src/passes/OptimizeInstructions.wast b/src/passes/OptimizeInstructions.wast
index 48a4e2c9d..d5f8148ec 100644
--- a/src/passes/OptimizeInstructions.wast
+++ b/src/passes/OptimizeInstructions.wast
@@ -34,6 +34,21 @@
         (call_import $any.expr (i32.const 1))
       )
     )
+    ;; eqz^2 is eliminatable if the output is boolean (note that for if-else, the above rule handles it in two operations)
+    (block
+      (if
+        (i32.eqz
+          (i32.eqz
+            (call_import $i32.expr (i32.const 0))
+          )
+        )
+        (call_import $any.expr (i32.const 1))
+      )
+      (if
+        (call_import $i32.expr (i32.const 0))
+        (call_import $any.expr (i32.const 1))
+      )
+    )
     ;; equal 0 => eqz
     (block
       (i32.eq
diff --git a/src/passes/OptimizeInstructions.wast.processed b/src/passes/OptimizeInstructions.wast.processed
index 13ccc8241..78e5e7476 100644
--- a/src/passes/OptimizeInstructions.wast.processed
+++ b/src/passes/OptimizeInstructions.wast.processed
@@ -34,6 +34,21 @@
 "(call_import $any.expr (i32.const 1))\n"
 ")\n"
 ")\n"
+";; eqz^2 is eliminatable if the output is boolean (note that for if-else, the above rule handles it in two operations)\n"
+"(block\n"
+"(if\n"
+"(i32.eqz\n"
+"(i32.eqz\n"
+"(call_import $i32.expr (i32.const 0))\n"
+")\n"
+")\n"
+"(call_import $any.expr (i32.const 1))\n"
+")\n"
+"(if\n"
+"(call_import $i32.expr (i32.const 0))\n"
+"(call_import $any.expr (i32.const 1))\n"
+")\n"
+")\n"
 ";; equal 0 => eqz\n"
 "(block\n"
 "(i32.eq\n"