Don't use a temporary file.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160686 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/regparm-flag.c b/test/CodeGen/regparm-flag.c
index 8ecf539..1330663 100644
--- a/test/CodeGen/regparm-flag.c
+++ b/test/CodeGen/regparm-flag.c
@@ -1,5 +1,4 @@
-// RUN: %clang_cc1 -triple i386-unknown-unknown -mregparm 4 %s -emit-llvm -o %t
-// RUN: FileCheck < %t %s
+// RUN: %clang_cc1 -triple i386-unknown-unknown -mregparm 4 %s -emit-llvm -o - | FileCheck %s
 
 void f1(int a, int b, int c, int d,
         int e, int f, int g, int h);