diff --git a/ext/bcmath/bcmath.c b/ext/bcmath/bcmath.c
index 7eae0729d85..8bb251dfb7d 100644
--- a/ext/bcmath/bcmath.c
+++ b/ext/bcmath/bcmath.c
@@ -132,9 +132,9 @@ PHP_MINFO_FUNCTION(bcmath)
 
 /* {{{ php_str2num
    Convert to bc_num detecting scale */
-static zend_result php_str2num(bc_num *num, char *str)
+static zend_result php_str2num(bc_num *num, const zend_string *str)
 {
-	if (!bc_str2num(num, str, 0, true)) {
+	if (!bc_str2num(num, ZSTR_VAL(str), ZSTR_VAL(str) + ZSTR_LEN(str), 0, true)) {
 		return FAILURE;
 	}
 
@@ -167,12 +167,12 @@ PHP_FUNCTION(bcadd)
 		scale = (int) scale_param;
 	}
 
-	if (php_str2num(&first, ZSTR_VAL(left)) == FAILURE) {
+	if (php_str2num(&first, left) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (php_str2num(&second, ZSTR_VAL(right)) == FAILURE) {
+	if (php_str2num(&second, right) == FAILURE) {
 		zend_argument_value_error(2, "is not well-formed");
 		goto cleanup;
 	}
@@ -214,12 +214,12 @@ PHP_FUNCTION(bcsub)
 		scale = (int) scale_param;
 	}
 
-	if (php_str2num(&first, ZSTR_VAL(left)) == FAILURE) {
+	if (php_str2num(&first, left) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (php_str2num(&second, ZSTR_VAL(right)) == FAILURE) {
+	if (php_str2num(&second, right) == FAILURE) {
 		zend_argument_value_error(2, "is not well-formed");
 		goto cleanup;
 	}
@@ -261,12 +261,12 @@ PHP_FUNCTION(bcmul)
 		scale = (int) scale_param;
 	}
 
-	if (php_str2num(&first, ZSTR_VAL(left)) == FAILURE) {
+	if (php_str2num(&first, left) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (php_str2num(&second, ZSTR_VAL(right)) == FAILURE) {
+	if (php_str2num(&second, right) == FAILURE) {
 		zend_argument_value_error(2, "is not well-formed");
 		goto cleanup;
 	}
@@ -310,12 +310,12 @@ PHP_FUNCTION(bcdiv)
 
 	bc_init_num(&result);
 
-	if (php_str2num(&first, ZSTR_VAL(left)) == FAILURE) {
+	if (php_str2num(&first, left) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (php_str2num(&second, ZSTR_VAL(right)) == FAILURE) {
+	if (php_str2num(&second, right) == FAILURE) {
 		zend_argument_value_error(2, "is not well-formed");
 		goto cleanup;
 	}
@@ -362,12 +362,12 @@ PHP_FUNCTION(bcmod)
 
 	bc_init_num(&result);
 
-	if (php_str2num(&first, ZSTR_VAL(left)) == FAILURE) {
+	if (php_str2num(&first, left) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (php_str2num(&second, ZSTR_VAL(right)) == FAILURE) {
+	if (php_str2num(&second, right) == FAILURE) {
 		zend_argument_value_error(2, "is not well-formed");
 		goto cleanup;
 	}
@@ -415,17 +415,17 @@ PHP_FUNCTION(bcpowmod)
 
 	bc_init_num(&result);
 
-	if (php_str2num(&bc_base, ZSTR_VAL(base_str)) == FAILURE) {
+	if (php_str2num(&bc_base, base_str) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (php_str2num(&bc_expo, ZSTR_VAL(exponent_str)) == FAILURE) {
+	if (php_str2num(&bc_expo, exponent_str) == FAILURE) {
 		zend_argument_value_error(2, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (php_str2num(&bc_modulus, ZSTR_VAL(modulus_str)) == FAILURE) {
+	if (php_str2num(&bc_modulus, modulus_str) == FAILURE) {
 		zend_argument_value_error(3, "is not well-formed");
 		goto cleanup;
 	}
@@ -489,12 +489,12 @@ PHP_FUNCTION(bcpow)
 
 	bc_init_num(&result);
 
-	if (php_str2num(&first, ZSTR_VAL(base_str)) == FAILURE) {
+	if (php_str2num(&first, base_str) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (php_str2num(&bc_exponent, ZSTR_VAL(exponent_str)) == FAILURE) {
+	if (php_str2num(&bc_exponent, exponent_str) == FAILURE) {
 		zend_argument_value_error(2, "is not well-formed");
 		goto cleanup;
 	}
@@ -546,7 +546,7 @@ PHP_FUNCTION(bcsqrt)
 		scale = (int) scale_param;
 	}
 
-	if (php_str2num(&result, ZSTR_VAL(left)) == FAILURE) {
+	if (php_str2num(&result, left) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
@@ -588,12 +588,12 @@ PHP_FUNCTION(bccomp)
 		scale = (int) scale_param;
 	}
 
-	if (!bc_str2num(&first, ZSTR_VAL(left), scale, false)) {
+	if (!bc_str2num(&first, ZSTR_VAL(left), ZSTR_VAL(left) + ZSTR_LEN(left), scale, false)) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
 
-	if (!bc_str2num(&second, ZSTR_VAL(right), scale, false)) {
+	if (!bc_str2num(&second, ZSTR_VAL(right), ZSTR_VAL(right) + ZSTR_LEN(right), scale, false)) {
 		zend_argument_value_error(2, "is not well-formed");
 		goto cleanup;
 	}
@@ -617,7 +617,7 @@ static void bcfloor_or_bcceil(INTERNAL_FUNCTION_PARAMETERS, bool is_floor)
 		Z_PARAM_STR(numstr)
 	ZEND_PARSE_PARAMETERS_END();
 
-	if (php_str2num(&num, ZSTR_VAL(numstr)) == FAILURE) {
+	if (php_str2num(&num, numstr) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
@@ -678,7 +678,7 @@ PHP_FUNCTION(bcround)
 
 	bc_init_num(&result);
 
-	if (php_str2num(&num, ZSTR_VAL(numstr)) == FAILURE) {
+	if (php_str2num(&num, numstr) == FAILURE) {
 		zend_argument_value_error(1, "is not well-formed");
 		goto cleanup;
 	}
diff --git a/ext/bcmath/libbcmath/src/bcmath.h b/ext/bcmath/libbcmath/src/bcmath.h
index 6b3b14bd159..23c8e8a749e 100644
--- a/ext/bcmath/libbcmath/src/bcmath.h
+++ b/ext/bcmath/libbcmath/src/bcmath.h
@@ -97,7 +97,7 @@ static inline bc_num bc_copy_num(bc_num num)
 
 void bc_init_num(bc_num *num);
 
-bool bc_str2num(bc_num *num, char *str, size_t scale, bool auto_scale);
+bool bc_str2num(bc_num *num, const char *str, const char *end, size_t scale, bool auto_scale);
 
 zend_string *bc_num2str_ex(bc_num num, size_t scale);
 
diff --git a/ext/bcmath/libbcmath/src/str2num.c b/ext/bcmath/libbcmath/src/str2num.c
index 79649a45781..8a94567a6f4 100644
--- a/ext/bcmath/libbcmath/src/str2num.c
+++ b/ext/bcmath/libbcmath/src/str2num.c
@@ -33,17 +33,55 @@
 #include "convert.h"
 #include <stdbool.h>
 #include <stddef.h>
+#ifdef __SSE2__
+# include <emmintrin.h>
+#endif
 
 /* Convert strings to bc numbers.  Base 10 only.*/
+static const char *bc_count_digits(const char *str, const char *end)
+{
+	/* Process in bulk */
+#ifdef __SSE2__
+	const __m128i offset = _mm_set1_epi8((signed char) (SCHAR_MIN - '0'));
+	/* we use the less than comparator, so add 1 */
+	const __m128i threshold = _mm_set1_epi8(SCHAR_MIN + ('9' + 1 - '0'));
+
+	while (str + sizeof(__m128i) <= end) {
+		__m128i bytes = _mm_loadu_si128((const __m128i *) str);
+		/* Wrapping-add the offset to the bytes, such that all bytes below '0' are positive and others are negative.
+		 * More specifically, '0' will be -128 and '9' will be -119. */
+		bytes = _mm_add_epi8(bytes, offset);
+		/* Now mark all bytes that are <= '9', i.e. <= -119, i.e. < -118, i.e. the threshold. */
+		bytes = _mm_cmplt_epi8(bytes, threshold);
+
+		int mask = _mm_movemask_epi8(bytes);
+		if (mask != 0xffff) {
+			/* At least one of the bytes is not within range. Move to the first offending byte. */
+#ifdef PHP_HAVE_BUILTIN_CTZL
+			return str + __builtin_ctz(~mask);
+#else
+			break;
+#endif
+		}
+
+		str += sizeof(__m128i);
+	}
+#endif
+
+	while (*str >= '0' && *str <= '9') {
+		str++;
+	}
+
+	return str;
+}
 
 /* Assumes `num` points to NULL, i.e. does yet not hold a number. */
-bool bc_str2num(bc_num *num, char *str, size_t scale, bool auto_scale)
+bool bc_str2num(bc_num *num, const char *str, const char *end, size_t scale, bool auto_scale)
 {
-	size_t digits = 0;
 	size_t str_scale = 0;
-	char *ptr = str;
-	char *fractional_ptr = NULL;
-	char *fractional_end = NULL;
+	const char *ptr = str;
+	const char *fractional_ptr = NULL;
+	const char *fractional_end = NULL;
 	bool zero_int = false;
 
 	ZEND_ASSERT(*num == NULL);
@@ -59,12 +97,10 @@ bool bc_str2num(bc_num *num, char *str, size_t scale, bool auto_scale)
 	}
 	const char *integer_ptr = ptr;
 	/* digits before the decimal point */
-	while (*ptr >= '0' && *ptr <= '9') {
-		ptr++;
-		digits++;
-	}
+	ptr = bc_count_digits(ptr, end);
+	size_t digits = ptr - integer_ptr;
 	/* decimal point */
-	char *decimal_point = (*ptr == '.') ? ptr : NULL;
+	const char *decimal_point = (*ptr == '.') ? ptr : NULL;
 
 	/* If a non-digit and non-decimal-point indicator is in the string, i.e. an invalid character */
 	if (!decimal_point && *ptr != '\0') {
@@ -80,14 +116,17 @@ bool bc_str2num(bc_num *num, char *str, size_t scale, bool auto_scale)
 		}
 
 		/* validate */
-		while (*fractional_ptr >= '0' && *fractional_ptr <= '9') {
-			fractional_end = *fractional_ptr != '0' ? fractional_ptr + 1 : fractional_end;
-			fractional_ptr++;
-		}
-		if (*fractional_ptr != '\0') {
+		fractional_end = bc_count_digits(fractional_ptr, end);
+		if (*fractional_end != '\0') {
 			/* invalid num */
 			goto fail;
 		}
+
+		/* Exclude trailing zeros. */
+		while (fractional_end - 1 > decimal_point && fractional_end[-1] == '0') {
+			fractional_end--;
+		}
+
 		/* Move the pointer to the beginning of the fraction. */
 		fractional_ptr = decimal_point + 1;