diff --git a/aom_dsp/ans.c b/aom_dsp/ans.c
index 18f6d480f..e1aaa0a38 100644
--- a/aom_dsp/ans.c
+++ b/aom_dsp/ans.c
@@ -15,15 +15,6 @@
 #include "aom_dsp/ans.h"
 #include "aom_dsp/prob.h"
 
-void aom_rans_build_cdf_from_pdf(const AnsP10 token_probs[], rans_lut cdf_tab) {
-  int i;
-  cdf_tab[0] = 0;
-  for (i = 1; cdf_tab[i - 1] < RANS_PRECISION; ++i) {
-    cdf_tab[i] = cdf_tab[i - 1] + token_probs[i - 1];
-  }
-  assert(cdf_tab[i - 1] == RANS_PRECISION);
-}
-
 static int find_largest(const AnsP10 *const pdf_tab, int num_syms) {
   int largest_idx = -1;
   int largest_p = -1;
diff --git a/aom_dsp/ans.h b/aom_dsp/ans.h
index e92c5305c..dd244cffd 100644
--- a/aom_dsp/ans.h
+++ b/aom_dsp/ans.h
@@ -39,8 +39,6 @@ typedef uint16_t AnsP10;
 // This is now just a boring cdf.
 typedef uint16_t rans_lut[16];
 
-void aom_rans_build_cdf_from_pdf(const AnsP10 token_probs[], rans_lut cdf_tab);
-
 void aom_rans_merge_prob8_pdf(AnsP10 *const out_pdf, const AnsP8 node_prob,
                               const AnsP10 *const src_pdf, int in_syms);
 #ifdef __cplusplus