PR78468 - add alloca alignment test

Add an alignment test to check that aligned alloca's really do get
correctly aligned.  Some targets may not ensure SP is always a multiple
of STACK_BOUNDARY (particularly with outgoing arguments), which means
aligned alloca does not get correctly aligned.  This can be fixed either
by aligning the outgoing arguments or setting STACK_BOUNDARY correctly.

    testsuite/
        PR middle-end/78468
	* gcc.dg/pr78468.c: Add alignment test.

From-SVN: r251811

2 files changed, 107 insertions, 0 deletions

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index cd283c0..3b850fb 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-09-06  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	PR middle-end/78468
+	* gcc.dg/pr78468.c: Add alignment test.
+
 2017-09-06  Wish Wu  <wishwu007@gmail.com>
 	    Jakub Jelinek  <jakub@redhat.com>
 
diff --git a/gcc/testsuite/gcc.dg/pr78468.c b/gcc/testsuite/gcc.dg/pr78468.c
new file mode 100644
index 0000000..a882d9a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr78468.c
@@ -0,0 +1,102 @@
+/* { dg-do run } */
+/* { dg-require-effective-target alloca } */
+/* { dg-options "-O2 -fno-inline" } */
+
+/* Test that targets correctly round the size of the outgoing arguments
+   to a multiple of STACK_BOUNDARY.  There is a serious alignment bug if
+   aligned alloca does not get aligned!  */
+
+__extension__ typedef __UINTPTR_TYPE__ uintptr_t;
+extern void abort (void);
+
+volatile int xx;
+volatile int x = 16;
+
+void
+t1 (int x0, int x1, int x2, int x3, int x4, int x5, int x6, int x7,
+    void *p, int align)
+{
+  xx = x0 + x1 + x2 + x3 + x4 + x4 + x6 + x7;
+  if ((int)(uintptr_t)p & (align-1))
+    abort ();
+}
+
+void
+t2 (int x0, int x1, int x2, int x3, int x4, int x5, int x6, int x7,
+    void *p, int align, int dummy)
+{
+  xx = x0 + x1 + x2 + x3 + x4 + x4 + x6 + x7;
+  if ((int)(uintptr_t)p & (align-1))
+    abort ();
+}
+
+void
+t1_a4 (int size)
+{
+  void *p = __builtin_alloca_with_align (size, 32);
+  t1 (0, 0, 0, 0, 0, 0, 0, 0, p, 4);
+}
+
+void
+t2_a4 (int size)
+{
+  void *p = __builtin_alloca_with_align (size, 32);
+  t2 (0, 0, 0, 0, 0, 0, 0, 0, p, 4, 0);
+}
+
+void
+t1_a8 (int size)
+{
+  void *p = __builtin_alloca_with_align (size, 64);
+  t1 (0, 0, 0, 0, 0, 0, 0, 0, p, 8);
+}
+
+void
+t2_a8 (int size)
+{
+  void *p = __builtin_alloca_with_align (size, 64);
+  t2 (0, 0, 0, 0, 0, 0, 0, 0, p, 8, 0);
+}
+
+void
+t1_a16 (int size)
+{
+  void *p = __builtin_alloca_with_align (size, 128);
+  t1 (0, 0, 0, 0, 0, 0, 0, 0, p, 16);
+}
+
+void
+t2_a16 (int size)
+{
+  void *p = __builtin_alloca_with_align (size, 128);
+  t2 (0, 0, 0, 0, 0, 0, 0, 0, p, 16, 0);
+}
+
+void
+t1_a32 (int size)
+{
+  void *p = __builtin_alloca_with_align (size, 256);
+  t1 (0, 0, 0, 0, 0, 0, 0, 0, p, 32);
+}
+
+void
+t2_a32 (int size)
+{
+  void *p = __builtin_alloca_with_align (size, 256);
+  t2 (0, 0, 0, 0, 0, 0, 0, 0, p, 32, 0);
+}
+
+
+int
+main ()
+{
+  t1_a4 (x);
+  t2_a4 (x);
+  t1_a8 (x);
+  t2_a8 (x);
+  t1_a16 (x);
+  t2_a16 (x);
+  t1_a32 (x);
+  t2_a32 (x);
+  return 0;
+}