Don't evaluate GMP comparison multiple times (php#18321)

nielsdos · web-flow · commit a142f10aa113 · 2025-04-14T11:19:14.000+02:00
ZEND_THREEWAY_COMPARE evaluates its operands multiple times.
diff --git a/ext/gmp/gmp.c b/ext/gmp/gmp.c
@@ -480,7 +480,8 @@ static int gmp_compare(zval *op1, zval *op2) /* {{{ */
 		return ZEND_UNCOMPARABLE;
 	}
 
-	return ZEND_THREEWAY_COMPARE(mpz_cmp(gmp_op1, gmp_op2), 0);
+	int ret = mpz_cmp(gmp_op1, gmp_op2); /* avoid multiple evaluations */
+	return ZEND_THREEWAY_COMPARE(ret, 0);
 }
 /* }}} */
 
@@ -1422,7 +1423,8 @@ ZEND_FUNCTION(gmp_cmp)
 		GMP_Z_PARAM_INTO_MPZ_PTR(gmpnum_b)
 	ZEND_PARSE_PARAMETERS_END();
 
-	RETURN_LONG(ZEND_THREEWAY_COMPARE(mpz_cmp(gmpnum_a, gmpnum_b), 0));
+	int ret = mpz_cmp(gmpnum_a, gmpnum_b); /* avoid multiple evaluations */
+	RETURN_LONG(ZEND_THREEWAY_COMPARE(ret, 0));
 }
 /* }}} */
 

Original file line number	Diff line number	Diff line change
`@@ -480,7 +480,8 @@ static int gmp_compare(zval op1, zval op2) /* {{{ */`
`480`	`480`	`return ZEND_UNCOMPARABLE;`
`481`	`481`	`}`
`482`	`482`
`483`		`- return ZEND_THREEWAY_COMPARE(mpz_cmp(gmp_op1, gmp_op2), 0);`
	`483`	`+ int ret = mpz_cmp(gmp_op1, gmp_op2); /* avoid multiple evaluations */`
	`484`	`+ return ZEND_THREEWAY_COMPARE(ret, 0);`
`484`	`485`	`}`
`485`	`486`	`/* }}} */`
`486`	`487`
`@@ -1422,7 +1423,8 @@ ZEND_FUNCTION(gmp_cmp)`
`1422`	`1423`	`GMP_Z_PARAM_INTO_MPZ_PTR(gmpnum_b)`
`1423`	`1424`	`ZEND_PARSE_PARAMETERS_END();`
`1424`	`1425`
`1425`		`- RETURN_LONG(ZEND_THREEWAY_COMPARE(mpz_cmp(gmpnum_a, gmpnum_b), 0));`
	`1426`	`+ int ret = mpz_cmp(gmpnum_a, gmpnum_b); /* avoid multiple evaluations */`
	`1427`	`+ RETURN_LONG(ZEND_THREEWAY_COMPARE(ret, 0));`
`1426`	`1428`	`}`
`1427`	`1429`	`/* }}} */`
`1428`	`1430`