diff --git a/c/bitvector-ops.c b/c/bitvector-ops.c
index 8365851..b59f20a 100644
--- a/c/bitvector-ops.c
+++ b/c/bitvector-ops.c
@@ -133,7 +133,7 @@ void bitvector_shl_to(uint32_t *dest, uint32_t *b, size_t n, uint32_t s,
 // assumes offs < 32
 void bitvector_fill(uint32_t *b, uint32_t offs, uint32_t c, uint32_t nbits)
 {
-    index_t i;
+    uintptr_t i;
     uint32_t nw, tail;
     uint32_t mask;
 
@@ -177,7 +177,7 @@ void bitvector_fill(uint32_t *b, uint32_t offs, uint32_t c, uint32_t nbits)
 
 void bitvector_not(uint32_t *b, uint32_t offs, uint32_t nbits)
 {
-    index_t i;
+    uintptr_t i;
     uint32_t nw, tail;
     uint32_t mask;
 
@@ -212,7 +212,7 @@ void bitvector_not(uint32_t *b, uint32_t offs, uint32_t nbits)
     void bitvector_##name(uint32_t *dest, uint32_t doffs, uint32_t *src,     \
                           uint32_t soffs, uint32_t nbits)                    \
     {                                                                        \
-        index_t i;                                                           \
+        uintptr_t i;                                                         \
         uint32_t s, nw, tail, snw;                                           \
         uint32_t mask, scrap;                                                \
                                                                              \
@@ -331,7 +331,7 @@ s)
 void bitvector_reverse_to(uint32_t *dest, uint32_t *src, uint32_t soffs,
                           uint32_t nbits)
 {
-    index_t i;
+    uintptr_t i;
     uint32_t nw, tail;
 
     if (nbits == 0)
@@ -353,7 +353,7 @@ void bitvector_reverse_to(uint32_t *dest, uint32_t *src, uint32_t soffs,
 
 void bitvector_reverse(uint32_t *b, uint32_t offs, uint32_t nbits)
 {
-    index_t i;
+    uintptr_t i;
     uint32_t nw, tail;
     uint32_t *temp;
 
@@ -414,7 +414,7 @@ uint64_t bitvector_count(uint32_t *b, uint32_t offs, uint64_t nbits)
 
 uint32_t bitvector_any0(uint32_t *b, uint32_t offs, uint32_t nbits)
 {
-    index_t i;
+    uintptr_t i;
     uint32_t nw, tail;
     uint32_t mask;
 
@@ -452,7 +452,7 @@ uint32_t bitvector_any0(uint32_t *b, uint32_t offs, uint32_t nbits)
 
 uint32_t bitvector_any1(uint32_t *b, uint32_t offs, uint32_t nbits)
 {
-    index_t i;
+    uintptr_t i;
     uint32_t nw, tail;
     uint32_t mask;
 
diff --git a/c/dtypes.h b/c/dtypes.h
index 53b6845..6d81908 100644
--- a/c/dtypes.h
+++ b/c/dtypes.h
@@ -104,11 +104,9 @@ typedef int bool_t;
 #ifdef BITS64
 #define TOP_BIT 0x8000000000000000
 #define NBITS 64
-typedef uint64_t index_t;
 #else
 #define TOP_BIT 0x80000000
 #define NBITS 32
-typedef uint32_t index_t;
 #endif
 
 #define LLT_ALIGN(x, sz) (((x) + (sz - 1)) & (-sz))
diff --git a/c/htable_inc.h b/c/htable_inc.h
index 12c6c53..0cb37ef 100644
--- a/c/htable_inc.h
+++ b/c/htable_inc.h
@@ -23,7 +23,7 @@
         hv = HFUNC((uintptr_t)key);                                          \
     retry_bp:                                                                \
         iter = 0;                                                            \
-        index = (index_t)(hv & (sz - 1)) * 2;                                \
+        index = (uintptr_t)(hv & (sz - 1)) * 2;                              \
         sz *= 2;                                                             \
         orig = index;                                                        \
                                                                              \
@@ -99,7 +99,7 @@
         size_t sz = hash_size(h);                                            \
         size_t maxprobe = max_probe(sz);                                     \
         void **tab = h->table;                                               \
-        size_t index = (index_t)(HFUNC((uintptr_t)key) & (sz - 1)) * 2;      \
+        size_t index = (uintptr_t)(HFUNC((uintptr_t)key) & (sz - 1)) * 2;    \
         sz *= 2;                                                             \
         size_t orig = index;                                                 \
         size_t iter = 0;                                                     \