dont add the -Zmiri-seed flag twice

Author: RalfJung

tests/compiletest.rs

@@ -69,7 +69,7 @@ fn compile_fail(path: &str, target: &str, opt: bool) {
     run_tests("compile-fail", path, target, flags);
 }
 
-fn miri_pass(path: &str, target: &str, opt: bool) {
+fn miri_pass(path: &str, target: &str, opt: bool, noseed: bool) {
     let opt_str = if opt { " with optimizations" } else { "" };
     eprintln!("{}", format!(
         "## Running run-pass tests in {} against miri for target {}{}",
@@ -81,7 +81,7 @@ fn miri_pass(path: &str, target: &str, opt: bool) {
     let mut flags = Vec::new();
     if opt {
         flags.push("-Zmir-opt-level=3".to_owned());
-    } else {
+    } else if !noseed {
         // Run with intptrcast.  Avoid test matrix explosion by doing either this or opt-level=3.
         flags.push("-Zmiri-seed=".to_owned());
     }
@@ -107,7 +107,8 @@ fn get_target() -> String {
 }
 
 fn run_pass_miri(opt: bool) {
-    miri_pass("tests/run-pass", &get_target(), opt);
+    miri_pass("tests/run-pass", &get_target(), opt, false);
+    miri_pass("tests/run-pass-noseed", &get_target(), opt, true);
 }
 
 fn compile_fail_miri(opt: bool) {