optimize sign-extends to ne

3 files changed, 79 insertions, 2 deletions

diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index bb4748a97..ef18ea777 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -364,7 +364,7 @@ struct OptimizeInstructions : public WalkerPass<PostWalker<OptimizeInstructions,
         if (getMaxBits(ext) + extraShifts < bits) {
           return removeAlmostSignExt(binary);
         }
-      } else if (binary->op == EqInt32) {
+      } else if (binary->op == EqInt32 || binary->op == NeInt32) {
         if (auto* c = binary->right->dynCast<Const>()) {
           if (auto* ext = getSignExt(binary->left)) {
             // we are comparing a sign extend to a constant, which means we can use a cheaper zext
@@ -374,7 +374,7 @@ struct OptimizeInstructions : public WalkerPass<PostWalker<OptimizeInstructions,
             c->value = c->value.and_(Literal(lowBitMask(bits)));
             return binary;
           }
-          if (c->value.geti32() == 0) {
+          if (binary->op == EqInt32 && c->value.geti32() == 0) {
             // equal 0 => eqz
             return Builder(*getModule()).makeUnary(EqZInt32, binary->left);
           }
diff --git a/test/passes/optimize-instructions.txt b/test/passes/optimize-instructions.txt
index 03f0f7074..25f2dfaa1 100644
--- a/test/passes/optimize-instructions.txt
+++ b/test/passes/optimize-instructions.txt
@@ -1079,4 +1079,36 @@
       )
     )
   )
+  (func $sign-ext-ne (type $4) (param $0 i32) (param $1 i32)
+    (drop
+      (i32.ne
+        (i32.and
+          (get_local $0)
+          (i32.const 255)
+        )
+        (i32.const 232)
+      )
+    )
+    (drop
+      (i32.ne
+        (i32.and
+          (get_local $0)
+          (i32.const 255)
+        )
+        (i32.const 111)
+      )
+    )
+    (drop
+      (i32.ne
+        (i32.and
+          (get_local $0)
+          (i32.const 255)
+        )
+        (i32.and
+          (get_local $1)
+          (i32.const 255)
+        )
+      )
+    )
+  )
 )
diff --git a/test/passes/optimize-instructions.wast b/test/passes/optimize-instructions.wast
index c59bb3ade..191450897 100644
--- a/test/passes/optimize-instructions.wast
+++ b/test/passes/optimize-instructions.wast
@@ -1332,4 +1332,49 @@
       )
     )
   )
+  (func $sign-ext-ne (param $0 i32) (param $1 i32)
+    ;; ne of sign-ext to const, can be a zext
+    (drop
+      (i32.ne
+        (i32.shr_s
+          (i32.shl
+            (get_local $0)
+            (i32.const 24)
+          )
+          (i32.const 24)
+        )
+        (i32.const 65000)
+      )
+    )
+    (drop
+      (i32.ne
+        (i32.shr_s
+          (i32.shl
+            (get_local $0)
+            (i32.const 24)
+          )
+          (i32.const 24)
+        )
+        (i32.const 111)
+      )
+    )
+    (drop
+      (i32.ne
+        (i32.shr_s
+          (i32.shl
+            (get_local $0)
+            (i32.const 24)
+          )
+          (i32.const 24)
+        )
+        (i32.shr_s
+          (i32.shl
+            (get_local $1)
+            (i32.const 24)
+          )
+          (i32.const 24)
+        )
+      )
+    )
+  )
 )