1 files changed, 82 insertions, 4 deletions

diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index 20cdeee19..003f204a9 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -210,7 +210,7 @@ struct OptimizeInstructions
       return nullptr;
     }
     if (auto* binary = curr->dynCast<Binary>()) {
-      if (isSymmetric(binary)) {
+      if (isSymmetricOrRelational(binary)) {
         canonicalize(binary);
       }
     }
@@ -895,9 +895,12 @@ private:
   // Canonicalizing the order of a symmetric binary helps us
   // write more concise pattern matching code elsewhere.
   void canonicalize(Binary* binary) {
-    assert(isSymmetric(binary));
+    assert(isSymmetricOrRelational(binary));
     auto swap = [&]() {
       assert(canReorder(binary->left, binary->right));
+      if (binary->isRelational()) {
+        binary->op = reverseRelationalOp(binary->op);
+      }
       std::swap(binary->left, binary->right);
     };
     auto maybeSwap = [&]() {
@@ -2183,6 +2186,81 @@ private:
     }
   }
 
+  BinaryOp reverseRelationalOp(BinaryOp op) {
+    switch (op) {
+      case EqInt32:
+        return EqInt32;
+      case NeInt32:
+        return NeInt32;
+      case LtSInt32:
+        return GtSInt32;
+      case LtUInt32:
+        return GtUInt32;
+      case LeSInt32:
+        return GeSInt32;
+      case LeUInt32:
+        return GeUInt32;
+      case GtSInt32:
+        return LtSInt32;
+      case GtUInt32:
+        return LtUInt32;
+      case GeSInt32:
+        return LeSInt32;
+      case GeUInt32:
+        return LeUInt32;
+
+      case EqInt64:
+        return EqInt64;
+      case NeInt64:
+        return NeInt64;
+      case LtSInt64:
+        return GtSInt64;
+      case LtUInt64:
+        return GtUInt64;
+      case LeSInt64:
+        return GeSInt64;
+      case LeUInt64:
+        return GeUInt64;
+      case GtSInt64:
+        return LtSInt64;
+      case GtUInt64:
+        return LtUInt64;
+      case GeSInt64:
+        return LeSInt64;
+      case GeUInt64:
+        return LeUInt64;
+
+      case EqFloat32:
+        return EqFloat32;
+      case NeFloat32:
+        return NeFloat32;
+      case LtFloat32:
+        return GtFloat32;
+      case LeFloat32:
+        return GeFloat32;
+      case GtFloat32:
+        return LtFloat32;
+      case GeFloat32:
+        return LeFloat32;
+
+      case EqFloat64:
+        return EqFloat64;
+      case NeFloat64:
+        return NeFloat64;
+      case LtFloat64:
+        return GtFloat64;
+      case LeFloat64:
+        return GeFloat64;
+      case GtFloat64:
+        return LtFloat64;
+      case GeFloat64:
+        return LeFloat64;
+
+      default:
+        return InvalidBinary;
+    }
+  }
+
   BinaryOp makeUnsignedBinaryOp(BinaryOp op) {
     switch (op) {
       case DivSInt32:
@@ -2220,8 +2298,8 @@ private:
     }
   }
 
-  bool isSymmetric(Binary* binary) {
-    if (Properties::isSymmetric(binary)) {
+  bool isSymmetricOrRelational(Binary* binary) {
+    if (Properties::isSymmetric(binary) || binary->isRelational()) {
       return true;
     }
     switch (binary->op) {