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[PATCH][GCC] Make stackalign test LTO proof
- From: Andre Vieira <Andre dot SimoesDiasVieira at arm dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 12 Nov 2015 15:07:35 +0000
- Subject: [PATCH][GCC] Make stackalign test LTO proof
- Authentication-results: sourceware.org; auth=none
Hi,
This patch changes this testcase to make sure LTO will not optimize
away the assignment of the local array to a global variable which was
introduced to make sure stack space was made available for the test to work.
This is correct because LTO is supposed to optimize this global away
as at link time it knows this global will never be read. By adding a
read of the global, LTO will no longer optimize it away.
Tested by running regressions for this testcase for various ARM targets.
Is this OK to commit?
Thanks,
Andre Vieira
gcc/testsuite/ChangeLog:
2015-11-06 Andre Vieira <andre.simoesdiasvieira@arm.com>
* gcc.dg/torture/stackalign/builtin-return-1.c: Added read
to global such that a write is not optimized away by LTO.
From 6fbac447475c3b669baee84aa9d6291c3d09f1ab Mon Sep 17 00:00:00 2001
From: Andre Simoes Dias Vieira <andsim01@arm.com>
Date: Fri, 6 Nov 2015 13:13:47 +0000
Subject: [PATCH] keep the stack testsuite fix
---
gcc/testsuite/gcc.dg/torture/stackalign/builtin-return-1.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/gcc/testsuite/gcc.dg/torture/stackalign/builtin-return-1.c b/gcc/testsuite/gcc.dg/torture/stackalign/builtin-return-1.c
index af017532aeb3878ef7ad717a2743661a87a56b7d..1ccd109256de72419a3c71c2c1be6d07c423c005 100644
--- a/gcc/testsuite/gcc.dg/torture/stackalign/builtin-return-1.c
+++ b/gcc/testsuite/gcc.dg/torture/stackalign/builtin-return-1.c
@@ -39,5 +39,10 @@ int main(void)
if (bar(1) != 2)
abort();
+ /* Make sure there is a read of the global after the function call to bar
+ * such that LTO does not optimize away the assignment above. */
+ if (g != dummy)
+ abort();
+
return 0;
}
--
1.9.1