Use --vex-iropt-precise-memory-exns=yes for valgrind < 3.8.0

Author: bwoebi

run-tests.php

@@ -1877,11 +1877,13 @@ function run_test($php, $file, $env)
 		$env['ZEND_DONT_UNLOAD_MODULES'] = 1;
 
 		/* --vex-iropt-register-updates=allregs-at-mem-access is necessary for phpdbg watchpoint tests */
-		if (version_compare($valgrind_version, '3.3.0', '>=')) {
+		if (version_compare($valgrind_version, '3.8.0', '>=')) {
 			/* valgrind 3.3.0+ doesn't have --log-file-exactly option */
 			$cmd = "valgrind -q --tool=memcheck --trace-children=yes --vex-iropt-register-updates=allregs-at-mem-access --log-file=$memcheck_filename $cmd";
+		} elseif (version_compare($valgrind_version, '3.3.0', '>=')) {
+			$cmd = "valgrind -q --tool=memcheck --trace-children=yes --vex-iropt-precise-memory-exns=yes --log-file=$memcheck_filename $cmd";
 		} else {
-			$cmd = "valgrind -q --tool=memcheck --trace-children=yes --vex-iropt-register-updates=allregs-at-mem-access --log-file-exactly=$memcheck_filename $cmd";
+			$cmd = "valgrind -q --tool=memcheck --trace-children=yes --vex-iropt-precise-memory-exns=yes --log-file-exactly=$memcheck_filename $cmd";
 		}
 
 	} else {