diff --git a/ext/bcmath/bcmath.c b/ext/bcmath/bcmath.c
index 962f839ba83f..1e0e6d14d81e 100644
--- a/ext/bcmath/bcmath.c
+++ b/ext/bcmath/bcmath.c
@@ -1164,7 +1164,7 @@ static zend_always_inline bcmath_number_obj_t *bcmath_number_new_obj(bc_num ret,
 	return intern;
 }
 
-static zend_result bcmath_number_parse_num(zval *zv, zend_object **obj, zend_string **str, zend_long *lval)
+static zend_result bcmath_number_parse_num(const zval *zv, zend_object **obj, zend_string **str, zend_long *lval)
 {
 	if (Z_TYPE_P(zv) == IS_OBJECT && instanceof_function(Z_OBJCE_P(zv), bcmath_number_ce)) {
 		*obj = Z_OBJ_P(zv);
@@ -1372,7 +1372,7 @@ static int bcmath_number_compare(zval *op1, zval *op2)
  	}
 
 static zend_always_inline zend_result bc_num_from_obj_or_str_or_long_with_err(
-	bc_num *num, size_t *scale, zend_object *obj, zend_string *str, zend_long lval, uint32_t arg_num)
+	bc_num *num, size_t *scale, const zend_object *obj, const zend_string *str, zend_long lval, uint32_t arg_num)
 {
 	size_t full_scale = 0;
 	if (UNEXPECTED(bc_num_from_obj_or_str_or_long(num, &full_scale, obj, str, lval) == FAILURE)) {
diff --git a/ext/bcmath/libbcmath/src/compare.c b/ext/bcmath/libbcmath/src/compare.c
index 2c24dab77705..06ef24678208 100644
--- a/ext/bcmath/libbcmath/src/compare.c
+++ b/ext/bcmath/libbcmath/src/compare.c
@@ -41,8 +41,6 @@
 
 bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, size_t scale, bool use_sign)
 {
-	char *n1ptr, *n2ptr;
-
 	/* First, compare signs. */
 	if (use_sign && n1->n_sign != n2->n_sign) {
 		/*
@@ -91,8 +89,8 @@ bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, size_t scale, bool us
 	/* If we get here, they have the same number of integer digits.
 	   check the integer part and the equal length part of the fraction. */
 	size_t count = n1->n_len + MIN (n1_scale, n2_scale);
-	n1ptr = n1->n_value;
-	n2ptr = n2->n_value;
+	const char *n1ptr = n1->n_value;
+	const char *n2ptr = n2->n_value;
 
 	while ((count > 0) && (*n1ptr == *n2ptr)) {
 		n1ptr++;
diff --git a/ext/bcmath/libbcmath/src/div.c b/ext/bcmath/libbcmath/src/div.c
index 1cf8a434c860..24ec9a64d77f 100644
--- a/ext/bcmath/libbcmath/src/div.c
+++ b/ext/bcmath/libbcmath/src/div.c
@@ -70,7 +70,7 @@ static inline void bc_fast_div(
  */
 static inline void bc_standard_div(
 	BC_VECTOR *numerator_vectors, size_t numerator_arr_size,
-	BC_VECTOR *divisor_vectors, size_t divisor_arr_size, size_t divisor_len,
+	const BC_VECTOR *divisor_vectors, size_t divisor_arr_size, size_t divisor_len,
 	BC_VECTOR *quot_vectors, size_t quot_arr_size
 ) {
 	size_t numerator_top_index = numerator_arr_size - 1;
@@ -354,10 +354,10 @@ bool bc_divide(bc_num numerator, bc_num divisor, bc_num *quot, size_t scale)
 		return true;
 	}
 
-	char *numeratorptr = numerator->n_value;
+	const char *numeratorptr = numerator->n_value;
 	size_t numerator_size = numerator->n_len + quot_scale + divisor->n_scale;
 
-	char *divisorptr = divisor->n_value;
+	const char *divisorptr = divisor->n_value;
 	size_t divisor_size = divisor->n_len + divisor->n_scale;
 
 	/* check and remove numerator leading zeros */
diff --git a/ext/bcmath/libbcmath/src/doaddsub.c b/ext/bcmath/libbcmath/src/doaddsub.c
index feb50120c70c..f516f2bda72d 100644
--- a/ext/bcmath/libbcmath/src/doaddsub.c
+++ b/ext/bcmath/libbcmath/src/doaddsub.c
@@ -46,7 +46,7 @@ bc_num _bc_do_add(bc_num n1, bc_num n2)
 	size_t min_len = MIN (n1->n_len, n2->n_len);
 	size_t min_scale = MIN(n1->n_scale, n2->n_scale);
 	size_t min_bytes = min_len + min_scale;
-	char *n1ptr, *n2ptr, *sumptr;
+	char *sumptr;
 	bool carry = 0;
 	size_t count;
 
@@ -54,8 +54,8 @@ bc_num _bc_do_add(bc_num n1, bc_num n2)
 	sum = bc_new_num_nonzeroed(sum_len, sum_scale);
 
 	/* Start with the fraction part.  Initialize the pointers. */
-	n1ptr = (char *) (n1->n_value + n1->n_len + n1->n_scale - 1);
-	n2ptr = (char *) (n2->n_value + n2->n_len + n2->n_scale - 1);
+	const char *n1ptr = (char *) (n1->n_value + n1->n_len + n1->n_scale - 1);
+	const char *n2ptr = (char *) (n2->n_value + n2->n_len + n2->n_scale - 1);
 	sumptr = (char *) (sum->n_value + sum_scale + sum_len - 1);
 
 	/* Add the fraction part.  First copy the longer fraction.*/
@@ -182,14 +182,14 @@ bc_num _bc_do_sub(bc_num n1, bc_num n2)
 	size_t borrow = 0;
 	size_t count;
 	int val;
-	char *n1ptr, *n2ptr, *diffptr;
+	char *diffptr;
 
 	/* Allocate temporary storage. */
 	diff = bc_new_num_nonzeroed(diff_len, diff_scale);
 
 	/* Initialize the subtract. */
-	n1ptr = (char *) (n1->n_value + n1->n_len + n1->n_scale - 1);
-	n2ptr = (char *) (n2->n_value + n2->n_len + n2->n_scale - 1);
+	const char *n1ptr = (char *) (n1->n_value + n1->n_len + n1->n_scale - 1);
+	const char *n2ptr = (char *) (n2->n_value + n2->n_len + n2->n_scale - 1);
 	diffptr = (char *) (diff->n_value + diff_len + diff_scale - 1);
 
 	/* Take care of the longer scaled number. */