diff --git a/loopy/symbolic.py b/loopy/symbolic.py
index 33bd620af45c71242ea263a9b3975bbf2d47f4ea..8e3d5d8fb3b30ca332fb132f7e2f2c2dfcb260c3 100644
--- a/loopy/symbolic.py
+++ b/loopy/symbolic.py
@@ -57,6 +57,8 @@ from pymbolic.mapper.constant_folder import \
 
 from pymbolic.parser import Parser as ParserBase
 
+from loopy.diagnostic import LoopyError
+
 import islpy as isl
 from islpy import dim_type
 
@@ -1054,7 +1056,7 @@ class ArrayAccessFinder(CombineMapper):
 
 # {{{ (pw)aff to expr conversion
 
-def aff_to_expr(aff):
+def aff_to_expr(aff, _floor=False):
     from pymbolic import var
 
     denom = aff.get_denominator_val().to_python()
@@ -1070,9 +1072,16 @@ def aff_to_expr(aff):
     for i in range(aff.dim(dim_type.div)):
         coeff = (aff.get_coefficient_val(dim_type.div, i)*denom).to_python()
         if coeff:
-            result += coeff*aff_to_expr(aff.get_div(i))
+            result += coeff*aff_to_expr(aff.get_div(i), _floor=True)
 
-    return result // denom
+    if _floor:
+        return result // denom
+    else:
+        if denom != 1:
+            raise LoopyError("integer expression with true division: %s"
+                    % aff)
+        else:
+            return result
 
 
 def pw_aff_to_expr(pw_aff, int_ok=False):