diff --git a/flang/include/flang/Optimizer/Dialect/FIROps.td b/flang/include/flang/Optimizer/Dialect/FIROps.td
--- a/flang/include/flang/Optimizer/Dialect/FIROps.td
+++ b/flang/include/flang/Optimizer/Dialect/FIROps.td
@@ -2606,6 +2606,7 @@
   let hasVerifier = 1;
 
   let extraClassDeclaration = [{
+    static bool isInteger(mlir::Type ty);
     static bool isIntegerCompatible(mlir::Type ty);
     static bool isFloatCompatible(mlir::Type ty);
     static bool isPointerCompatible(mlir::Type ty);
diff --git a/flang/lib/Optimizer/Dialect/FIROps.cpp b/flang/lib/Optimizer/Dialect/FIROps.cpp
--- a/flang/lib/Optimizer/Dialect/FIROps.cpp
+++ b/flang/lib/Optimizer/Dialect/FIROps.cpp
@@ -928,9 +928,12 @@
   return {};
 }
 
+bool fir::ConvertOp::isInteger(mlir::Type ty) {
+  return ty.isa<mlir::IntegerType, mlir::IndexType, fir::IntegerType>();
+}
+
 bool fir::ConvertOp::isIntegerCompatible(mlir::Type ty) {
-  return ty.isa<mlir::IntegerType, mlir::IndexType, fir::IntegerType,
-                fir::LogicalType>();
+  return isInteger(ty) || mlir::isa<fir::LogicalType>(ty);
 }
 
 bool fir::ConvertOp::isFloatCompatible(mlir::Type ty) {
@@ -1001,8 +1004,8 @@
     return true;
   return (isPointerCompatible(inType) && isPointerCompatible(outType)) ||
          (isIntegerCompatible(inType) && isIntegerCompatible(outType)) ||
-         (isIntegerCompatible(inType) && isFloatCompatible(outType)) ||
-         (isFloatCompatible(inType) && isIntegerCompatible(outType)) ||
+         (isInteger(inType) && isFloatCompatible(outType)) ||
+         (isFloatCompatible(inType) && isInteger(outType)) ||
          (isFloatCompatible(inType) && isFloatCompatible(outType)) ||
          (isIntegerCompatible(inType) && isPointerCompatible(outType)) ||
          (isPointerCompatible(inType) && isIntegerCompatible(outType)) ||
diff --git a/flang/test/Fir/invalid.fir b/flang/test/Fir/invalid.fir
--- a/flang/test/Fir/invalid.fir
+++ b/flang/test/Fir/invalid.fir
@@ -946,3 +946,19 @@
   %zero = arith.constant 0 : i32
   return %zero : i32
 }
+
+// -----
+
+func.func @logical_to_fp(%arg0: !fir.logical<4>) -> f32 {
+  // expected-error@+1{{'fir.convert' op invalid type conversion}}
+  %0 = fir.convert %arg0 : (!fir.logical<4>) -> f32
+  return %0 : f32
+}
+
+// -----
+
+func.func @fp_to_logical(%arg0: f32) -> !fir.logical<4> {
+  // expected-error@+1{{'fir.convert' op invalid type conversion}}
+  %0 = fir.convert %arg0 : (f32) -> !fir.logical<4>
+  return %0 : !fir.logical<4>
+}