[gcc r12-7991] testsuite: Add -fno-tree-loop-distribute-patterns.

[Robin Dapp <rdapp@gcc.gnu.org>]

https://gcc.gnu.org/g:321d1dcf610d8af8da4c1feb76819fea24fcd27e

commit r12-7991-g321d1dcf610d8af8da4c1feb76819fea24fcd27e
Author: Robin Dapp <rdapp@linux.ibm.com>
Date:   Fri Apr 1 09:52:56 2022 +0200

    testsuite: Add -fno-tree-loop-distribute-patterns.
    
    In gcc.dg/Wuse-after-free-2.c we try to detect a use-after-free.  The
    test's while loop is converted into a rawmemchr builtin making
    it impossible to determine that the pointers *p and *q are related.
    
    Therefore, disable the tree loop distribute patterns pass for this test.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.dg/Wuse-after-free-2.c:
            Add -fno-tree-loop-distribute-patterns in order to avoid
            rawmemchr.

Diff:
---
 gcc/testsuite/gcc.dg/Wuse-after-free-2.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.dg/Wuse-after-free-2.c b/gcc/testsuite/gcc.dg/Wuse-after-free-2.c
index 9f7ed4529f0..68ec75845ce 100644
--- a/gcc/testsuite/gcc.dg/Wuse-after-free-2.c
+++ b/gcc/testsuite/gcc.dg/Wuse-after-free-2.c
@@ -1,6 +1,6 @@
 /* PR middle-end/104232 - spurious -Wuse-after-free after conditional free
    { dg-do compile }
-   { dg-options "-O2 -Wall" } */
+   { dg-options "-O2 -Wall -fno-tree-loop-distribute-patterns" }  */
 
 void free (void*);
 
@@ -107,6 +107,8 @@ int warn_cond_loop (char *p)
 {
   char *q = p;
 
+  /*  -fno-tree-loop-distribute-patterns ensures this does not get converted
+      into rawmemchr (making q and p unrelated).  */
   while (*q)
     ++q;