diff --git a/artiq/compiler/embedding.py b/artiq/compiler/embedding.py
index 380656e44..1c08bbdfe 100644
--- a/artiq/compiler/embedding.py
+++ b/artiq/compiler/embedding.py
@@ -747,9 +747,9 @@ class StitchingInferencer(Inferencer):
                 if elt.__class__ == float:
                     state |= IS_FLOAT
                 elif elt.__class__ == int:
-                    if -2**31 < elt < 2**31-1:
+                    if -2**31 <= elt <= 2**31-1:
                         state |= IS_INT32
-                    elif -2**63 < elt < 2**63-1:
+                    elif -2**63 <= elt <= 2**63-1:
                         state |= IS_INT64
                     else:
                         state = -1
diff --git a/artiq/compiler/transforms/int_monomorphizer.py b/artiq/compiler/transforms/int_monomorphizer.py
index adab3b165..5c7d22dce 100644
--- a/artiq/compiler/transforms/int_monomorphizer.py
+++ b/artiq/compiler/transforms/int_monomorphizer.py
@@ -14,9 +14,9 @@ class IntMonomorphizer(algorithm.Visitor):
     def visit_NumT(self, node):
         if builtins.is_int(node.type):
             if types.is_var(node.type["width"]):
-                if -2**31 < node.n < 2**31-1:
+                if -2**31 <= node.n <= 2**31-1:
                     width = 32
-                elif -2**63 < node.n < 2**63-1:
+                elif -2**63 <= node.n <= 2**63-1:
                     width = 64
                 else:
                     diag = diagnostic.Diagnostic("error",
diff --git a/artiq/coredevice/comm_kernel.py b/artiq/coredevice/comm_kernel.py
index b6ffb8ee7..73a480ef4 100644
--- a/artiq/coredevice/comm_kernel.py
+++ b/artiq/coredevice/comm_kernel.py
@@ -465,12 +465,12 @@ class CommKernel:
             self._write_bool(value)
         elif tag == "i":
             check(isinstance(value, (int, numpy.int32)) and
-                  (-2**31 <= value < 2**31),
+                  (-2**31 <= value <= 2**31-1),
                   lambda: "32-bit int")
             self._write_int32(value)
         elif tag == "I":
             check(isinstance(value, (int, numpy.int32, numpy.int64)) and
-                  (-2**63 <= value < 2**63),
+                  (-2**63 <= value <= 2**63-1),
                   lambda: "64-bit int")
             self._write_int64(value)
         elif tag == "f":
@@ -479,8 +479,8 @@ class CommKernel:
             self._write_float64(value)
         elif tag == "F":
             check(isinstance(value, Fraction) and
-                  (-2**63 <= value.numerator < 2**63) and
-                  (-2**63 <= value.denominator < 2**63),
+                  (-2**63 <= value.numerator <= 2**63-1) and
+                  (-2**63 <= value.denominator <= 2**63-1),
                   lambda: "64-bit Fraction")
             self._write_int64(value.numerator)
             self._write_int64(value.denominator)