add test

Author: devnexen

ext/gmp/gmp.c

@@ -1290,6 +1290,7 @@ ZEND_FUNCTION(gmp_pow)
 		INIT_GMP_RETVAL(gmpnum_result);
 		gmpnum = mpz_get_ui(gmpnum_base);
 		if ((log10(gmpnum) * exp) > (double)ULONG_MAX) {
+			FREE_GMP_TEMP(temp_base);
 			zend_value_error("base and exponent overflow");
 			RETURN_THROWS();
 		}

ext/gmp/tests/gmp_pow_fpe.phpt

@@ -0,0 +1,22 @@
+--TEST--
+gmp_pow() floating point exception
+--EXTENSIONS--
+gmp
+--FILE--
+<?php
+$g = gmp_init(256);
+
+try {
+	gmp_pow($g, PHP_INT_MAX);
+} catch (\ValueError $e) {
+	echo $e->getMessage() . PHP_EOL;
+}
+try {
+	gmp_pow(256, PHP_INT_MAX);
+} catch (\ValueError $e) {
+	echo $e->getMessage();
+}
+?>
+--EXPECT--
+base and exponent overflow
+base and exponent overflow