[PATCH] Fix PR64242

[Jakub Jelinek]

Hi!

Here is a fix for the testcase, so that it doesn't FAIL pretty much
everywhere.

On Fri, Nov 30, 2018 at 04:07:31PM -0700, Jeff Law wrote:
> > 	PR middle-end/64242
> > 	* gcc.c-torture/execute/pr64242.c: New test.
> THanks for tracking this down.  I'd like to have this run through my
> next testing cycle, so I went ahead and installed  it for you.

What I've tested:
1) x86_64-linux {-m32,-m64} - without the testcase patch, the testcase FAILs
   without or with the builtins.c change; with the testcase patch and
   witout the builtins.c change, there is
FAIL: gcc.c-torture/execute/pr64242.c   -O2  execution test
FAIL: gcc.c-torture/execute/pr64242.c   -O3 -g  execution test
FAIL: gcc.c-torture/execute/pr64242.c   -Os  execution test
   for -m32 and no FAILs for -m64, with the builtins.c change the tests
   passes on both -m32 and -m64
2) powerpc64-linux {-m32,-m64} - without the testcase patch, the testcase
   FAILs without and with the builtins.c change for -m32.  With the testcase
   patch and without the builtins.c change, there is
FAIL: gcc.c-torture/execute/pr64242.c   -O0  execution test
FAIL: gcc.c-torture/execute/pr64242.c   -O1  execution test
FAIL: gcc.c-torture/execute/pr64242.c   -O2  execution test
FAIL: gcc.c-torture/execute/pr64242.c   -O3 -g  execution test
FAIL: gcc.c-torture/execute/pr64242.c   -Os  execution test
   for -m32 and
FAIL: gcc.c-torture/execute/pr64242.c   -O0  execution test
FAIL: gcc.c-torture/execute/pr64242.c   -O1  execution test
   for -m64, with the builtins.c change everything passes
3) aarch64-linux - both without and with the testcase patch, the
   testcase FAILs without the builtins.c change and passes with it

Ok for trunk?

2018-12-03  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/64242
	* gcc.c-torture/execute/pr64242.c (foo, bar): New functions.
	(p): Make it void *volatile instead of volatile void *.
	(q): New variable.
	(main): Add a dummy 32-byte aligned variable and escape its address.
	Don't require that the two __builtin_alloca (0) calls return the
	same address, just require that their difference is smaller than
	1024 bytes.

--- gcc/testsuite/gcc.c-torture/execute/pr64242.c.jj	2018-12-01 00:25:08.082009500 +0100
+++ gcc/testsuite/gcc.c-torture/execute/pr64242.c	2018-12-03 16:51:51.869797742 +0100
@@ -3,7 +3,7 @@
 extern void abort (void);
 
 __attribute ((noinline)) void
-broken_longjmp(void *p)
+broken_longjmp (void *p)
 {
   void *buf[5];
   __builtin_memcpy (buf, p, 5 * sizeof (void*));
@@ -11,20 +11,41 @@ broken_longjmp(void *p)
   __builtin_longjmp (buf, 1);
 }
 
+__attribute ((noipa)) __UINTPTR_TYPE__
+foo (void *p)
+{
+  return (__UINTPTR_TYPE__) p;
+}
+
+__attribute ((noipa)) void
+bar (void *p)
+{
+  asm volatile ("" : : "r" (p));
+}
+
 volatile int x = 0;
-volatile void *p;
+void *volatile p;
+void *volatile q;
+
 int
-main (void)
+main ()
 {
   void *buf[5];
+  struct __attribute__((aligned (32))) S { int a[4]; } s;
+  bar (&s);
   p = __builtin_alloca (x);
-
   if (!__builtin_setjmp (buf))
     broken_longjmp (buf);
 
   /* Fails if stack pointer corrupted.  */
-  if (p != __builtin_alloca (x))
-    abort();
+  q = __builtin_alloca (x);
+  if (foo (p) < foo (q))
+    {
+      if (foo (q) - foo (p) >= 1024)
+	abort ();
+    }
+  else if (foo (p) - foo (q) >= 1024)
+    abort ();
 
   return 0;
 }

	Jakub