diff --git a/devito/arch/compiler.py b/devito/arch/compiler.py
index 1faf77cc90..ef248cbdf0 100644
--- a/devito/arch/compiler.py
+++ b/devito/arch/compiler.py
@@ -22,7 +22,7 @@
 from devito.logger import debug, warning
 from devito.parameters import configuration
 from devito.tools import (
-    as_list, change_directory, filter_ordered, make_tempdir, memoized_func
+    Signer, as_list, change_directory, filter_ordered, make_tempdir, memoized_func
 )
 
 __all__ = ['compiler_registry', 'sniff_mpi_distro']
@@ -148,7 +148,7 @@ def call_capture_output(cmd):
     return _call_capture_output(cmd)
 
 
-class Compiler(GCCToolchain):
+class Compiler(GCCToolchain, Signer):
     """
     Base class for all compiler classes.
 
@@ -457,6 +457,9 @@ def __getstate__(self):
         # The superclass would otherwise only return a subset of attributes
         return self.__dict__
 
+    def _signature_items(self):
+        return (str(self._cmdline([])), self.src_ext, self.so_ext)
+
     def add_include_dirs(self, dirs):
         self.include_dirs = filter_ordered(self.include_dirs + as_list(dirs))
 
diff --git a/devito/operator/operator.py b/devito/operator/operator.py
index b3690caf74..8f3c02f983 100644
--- a/devito/operator/operator.py
+++ b/devito/operator/operator.py
@@ -811,7 +811,7 @@ def arguments(self, **kwargs):
     @cached_property
     def _soname(self):
         """A unique name for the shared object resulting from JIT compilation."""
-        return Signer._digest(self, configuration)
+        return Signer._digest(self, configuration, self._compiler)
 
     @cached_property
     def _printer(self):
diff --git a/tests/test_operator.py b/tests/test_operator.py
index 4518b32429..e6fc86463a 100644
--- a/tests/test_operator.py
+++ b/tests/test_operator.py
@@ -161,6 +161,43 @@ def test_compiler_uniqueness(self):
         assert op0._compiler is not op2._compiler
         assert op1._compiler is not op2._compiler
 
+    @pytest.mark.parametrize('rpath', [False, True])
+    def test_jit_library_dirs(self, rpath, tmp_path):
+        grid = Grid(shape=(3, 3, 3))
+        u = TimeFunction(name='u', grid=grid)
+        eq = Eq(u.forward, u + 1)
+
+        operators = []
+        for name in ('lib0', 'lib1', 'lib1'):
+            op = Operator(eq, name='library_paths')
+            op._compiler.add_library_dirs([str(tmp_path/name)], rpath=rpath)
+            operators.append(op)
+
+        op0, op1, op2 = operators
+        assert str(op0) == str(op1) == str(op2)
+        assert op0._soname != op1._soname
+        assert op1._soname == op2._soname
+
+    @pytest.mark.parametrize('envvar, flags', [
+        ('CFLAGS', ('-O1 -O2', '-O2 -O1')),
+        ('LDFLAGS', ('-Wl,-rpath,/lib0 -Wl,-rpath,/lib1',
+                     '-Wl,-rpath,/lib1 -Wl,-rpath,/lib0'))
+    ])
+    def test_jit_compiler_flags(self, envvar, flags, monkeypatch):
+        grid = Grid(shape=(3, 3, 3))
+        u = TimeFunction(name='u', grid=grid)
+        eq = Eq(u.forward, u + 1)
+
+        operators = []
+        for value in (*flags, flags[-1]):
+            monkeypatch.setenv(envvar, value)
+            operators.append(Operator(eq, name='compiler_flags', compiler='custom'))
+
+        op0, op1, op2 = operators
+        assert str(op0) == str(op1) == str(op2)
+        assert op0._soname != op1._soname
+        assert op1._soname == op2._soname
+
 
 class TestCodeGen: