diff --git a/ChangeLog.d/clang-15-bignum-warning.txt b/ChangeLog.d/clang-15-bignum-warning.txt
new file mode 100644
index 000000000..d3308b4c9
--- /dev/null
+++ b/ChangeLog.d/clang-15-bignum-warning.txt
@@ -0,0 +1,3 @@
+Bugfix
+   * Silence a warning about an unused local variable in bignum.c on
+     some architectures. Fixes #7166.
diff --git a/library/bignum.c b/library/bignum.c
index d915ade63..5dca3a917 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -1427,6 +1427,7 @@ void mpi_mul_hlp(size_t i,
                  mbedtls_mpi_uint b)
 {
     mbedtls_mpi_uint c = 0, t = 0;
+    (void) t;                   /* Unused in some architectures */
 
 #if defined(MULADDC_HUIT)
     for (; i >= 8; i -= 8) {
@@ -1472,8 +1473,6 @@ void mpi_mul_hlp(size_t i,
     }
 #endif /* MULADDC_HUIT */
 
-    t++;
-
     while (c != 0) {
         *d += c; c = (*d < c); d++;
     }