2 files changed, 97 insertions, 11 deletions

diff --git a/src/literal.h b/src/literal.h
index eedccabcc..33300c920 100644
--- a/src/literal.h
+++ b/src/literal.h
@@ -96,7 +96,57 @@ public:
     }
     return false;
   }
+  bool isZero() const {
+    switch (type.getBasic()) {
+      case Type::i32:
+        return i32 == 0;
+      case Type::i64:
+        return i64 == 0LL;
+      case Type::f32:
+        return bit_cast<float>(i32) == 0.0f;
+      case Type::f64:
+        return bit_cast<double>(i64) == 0.0;
+      case Type::v128: {
+        uint8_t zeros[16] = {0};
+        return memcmp(&v128, zeros, 16) == 0;
+      }
+      default:
+        WASM_UNREACHABLE("unexpected type");
+    }
+  }
+  bool isSignedMin() const {
+    switch (type.getBasic()) {
+      case Type::i32:
+        return i32 == std::numeric_limits<int32_t>::min();
+      case Type::i64:
+        return i64 == std::numeric_limits<int64_t>::min();
+      default:
+        WASM_UNREACHABLE("unexpected type");
+    }
+  }
+  bool isSignedMax() const {
+    switch (type.getBasic()) {
+      case Type::i32:
+        return i32 == std::numeric_limits<int32_t>::max();
+      case Type::i64:
+        return i64 == std::numeric_limits<int64_t>::max();
+      default:
+        WASM_UNREACHABLE("unexpected type");
+    }
+  }
+  bool isUnsignedMax() const {
+    switch (type.getBasic()) {
+      case Type::i32:
+        return uint32_t(i32) == std::numeric_limits<uint32_t>::max();
+      case Type::i64:
+        return uint64_t(i64) == std::numeric_limits<uint64_t>::max();
+      default:
+        WASM_UNREACHABLE("unexpected type");
+    }
+  }
 
+  static Literals makeZero(Type type);
+  static Literal makeSingleZero(Type type);
   static Literal makeFromInt32(int32_t x, Type type) {
     switch (type.getBasic()) {
       case Type::i32:
@@ -116,7 +166,6 @@ public:
         WASM_UNREACHABLE("unexpected type");
     }
   }
-
   static Literal makeFromUInt64(uint64_t x, Type type) {
     switch (type.getBasic()) {
       case Type::i32:
@@ -131,10 +180,36 @@ public:
         WASM_UNREACHABLE("unexpected type");
     }
   }
-
-  static Literals makeZero(Type type);
-  static Literal makeSingleZero(Type type);
-
+  static Literal makeSignedMin(Type type) {
+    switch (type.getBasic()) {
+      case Type::i32:
+        return Literal(std::numeric_limits<int32_t>::min());
+      case Type::i64:
+        return Literal(std::numeric_limits<int64_t>::min());
+      default:
+        WASM_UNREACHABLE("unexpected type");
+    }
+  }
+  static Literal makeSignedMax(Type type) {
+    switch (type.getBasic()) {
+      case Type::i32:
+        return Literal(std::numeric_limits<int32_t>::max());
+      case Type::i64:
+        return Literal(std::numeric_limits<int64_t>::max());
+      default:
+        WASM_UNREACHABLE("unexpected type");
+    }
+  }
+  static Literal makeUnsignedMax(Type type) {
+    switch (type.getBasic()) {
+      case Type::i32:
+        return Literal(std::numeric_limits<uint32_t>::max());
+      case Type::i64:
+        return Literal(std::numeric_limits<uint64_t>::max());
+      default:
+        WASM_UNREACHABLE("unexpected type");
+    }
+  }
   static Literal makeNull(Type type) {
     assert(type.isNullable());
     return Literal(type);
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index 79315ac6d..de96e418e 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -298,15 +298,16 @@ struct OptimizeInstructions
         }
       }
       {
-        // eqz((signed)x % C_pot)  =>  eqz(x & (C_pot - 1))
+        // eqz((signed)x % C_pot)  =>  eqz(x & (abs(C_pot) - 1))
         Const* c;
         Binary* inner;
         if (matches(curr,
                     unary(Abstract::EqZ,
                           binary(&inner, Abstract::RemS, any(), ival(&c)))) &&
-            Bits::isPowerOf2((uint64_t)c->value.getInteger())) {
+            !c->value.isSignedMin() &&
+            Bits::isPowerOf2(c->value.abs().getInteger())) {
           inner->op = Abstract::getBinary(c->type, Abstract::And);
-          c->value = c->value.sub(Literal::makeFromInt32(1, c->type));
+          c->value = c->value.abs().sub(Literal::makeFromInt32(1, c->type));
           return curr;
         }
       }
@@ -1307,7 +1308,16 @@ private:
       right->value = Literal::makeSingleZero(type);
       return right;
     }
-    // (signed)x % C_pot != 0   ==>  x & (C_pot - 1) != 0
+    {
+      // (signed)x % (i32|i64).min_s   ==>  (x & (i32|i64).max_s)
+      if (matches(curr, binary(Abstract::RemS, any(&left), ival())) &&
+          right->value.isSignedMin()) {
+        curr->op = Abstract::getBinary(type, Abstract::And);
+        right->value = Literal::makeSignedMax(type);
+        return curr;
+      }
+    }
+    // (signed)x % C_pot != 0   ==>  (x & (abs(C_pot) - 1)) != 0
     {
       Const* c;
       Binary* inner;
@@ -1315,9 +1325,10 @@ private:
                   binary(Abstract::Ne,
                          binary(&inner, Abstract::RemS, any(), ival(&c)),
                          ival(0))) &&
-          Bits::isPowerOf2((uint64_t)c->value.getInteger())) {
+          !c->value.isSignedMin() &&
+          Bits::isPowerOf2(c->value.abs().getInteger())) {
         inner->op = Abstract::getBinary(c->type, Abstract::And);
-        c->value = c->value.sub(Literal::makeFromInt32(1, c->type));
+        c->value = c->value.abs().sub(Literal::makeFromInt32(1, c->type));
         return curr;
       }
     }